PECAM-1: a multi-functional molecule in inflammation and vascular biology

Novel breast reconstruction technique using ex vivo mononuclear (RE-01) cells and adipose-derived mesenchymal stem cells

Introduction

Breast reconstruction using fat grafts presents challenges; for example, fat necrosis owing to inadequate blood flow results in reduced engraftment rates. Supplementation of adipose tissue with adipose-derived mesenchymal stem cells (ADSCs) to promote the rapid vascularization of transplanted tissue has been investigated. However, the vascularization of fat-grafted tissues using only ADSC transplantation is limited. Ex vivo cultured mononuclear cells (RE-01) are a cell population with highly vascular and tissue-regenerative properties. This study aimed to evaluate the effect of combining RE-01 cells and ADSCs on the engraftment rate of fat grafts and explore the potential of this approach as a new option for breast reconstruction surgery. We hypothesized that combining RE-01 with ADSCs might promote angiogenesis and improve the fat grafting rate, consequently reducing the number of ADSCs required.

Methods

ADSCs cultured from human adipose tissue discarded during liposuction were co-cultured with RE-01 cells produced from the peripheral blood of healthy volunteers. In vitro vascular regeneration and adipogenic differentiation potential were analyzed. In addition, fat grafting experiments were conducted using nude mice to verify the fat grafting efficacy of ADSCs after co-cultivation with RE-01.

Results

ADSCs co-cultured with RE-01 cells promoted angiogenesis and adipogenesis in vitro. This was evidenced by a significant increase in the expression of adipogenic markers FABP4 and PPARγ, as well as enhanced lipid droplet formation observed through Oil Red O staining. The in vivo results demonstrated that the fat engraftment rate was significantly improved in the mixed group of ADSCs co-cultured with RE-01 cells. The number of blood vessels and fat quality of the transplanted adipose tissue were also increased in this group, suggesting that ADSCs co-cultured with RE-01 cells were highly effective in fat transplantation.

Conclusions

ADSCs co-cultured with RE-01 cells may be useful for improving the engraftment rate of fat grafts. However, further studies are required to verify the mechanisms.

ST6GAL1-Mediated Sialylation of PECAM-1 Promotes a Transcellular Diapedesis-Like Process That Directs Lung Tropism of Metastatic Breast Cancer

Metastasis is the leading cause of mortality in breast cancer, with lung metastasis being particularly detrimental. Identification of the processes determining metastatic organotropism could enable the development of approaches to prevent and treat breast cancer metastasis. In this study, we found that lung-tropic and non-lung-tropic breast cancer cells differ in their response to sialic acids, affecting the sialylation of surface proteins. Lung-tropic cells showed higher levels of ST6GAL1, whereas non-lung-tropic cells had more ST3GAL1. ST6GAL1-mediated α-2,6-sialylation, unlike ST3GAL1-mediated α-2,3-sialylation, increased lung metastasis by promoting cancer cell migration through pulmonary endothelial layers and reducing junction protein levels. α-2,6-Sialylated platelet/endothelial cell adhesion molecule 1 (PECAM-1) on breast cancer cells facilitated extravasation through the pulmonary endothelium, a critical step in lung metastasis. Knockdown of ST6GAL1 or PECAM-1 significantly reduced lung metastasis. The human pulmonary endothelium displayed high PECAM-1 levels. Through transhomophilic interaction with pulmonary PECAM-1, α-2,6-sialylated PECAM-1 on ST6GAL1-positive cancer cells increased pulmonary extravasation in a diapedesis-like, cell-autonomous manner. Additionally, lung-tropic cells and their exosomes increased the permeability of pulmonary endothelial cells, promoting metastasis in a non-cell-autonomous manner. Analysis of human breast cancer samples showed a correlation between elevated ST6GAL1/PECAM-1 expression and lung metastasis. These results suggest that targeting ST6GAL1-mediated α-2,6-sialylation could be a potential therapeutic strategy to prevent lung metastasis in patients with breast cancer. Significance: ST6GAL1-mediated α-2,6-sialylation of PECAM-1 dictates lung-tropic metastasis of breast cancer, revealing that the pattern of sialylation of breast cancer cells is a determinant of metastatic organ tropism and a potential therapeutic target.

The Association Between Dysglycemia and Endotheliopathy in ICU Patients With and Without Diabetes: A Cohort Study

IMPORTANCE

Dysglycemia in critically ill patients is associated with endotheliopathy. This relationship may be altered in patients with diabetes.

OBJECTIVES

Dysglycemia is common in critically ill patients and associated with increased mortality. Endotheliopathy is thought to play a role in this relationship; however, evidence is scarce. The aim of this study was to investigate the associations between dysglycemia and endotheliopathy to inform future glycemic management.

DESIGN, SETTING, AND PARTICIPANTS

This prospective observational study included 577 acutely admitted adult ICU patients at Copenhagen University Hospital-North Zealand, Denmark.

MAIN OUTCOMES AND MEASURES

Up to twenty-four hours of patient glycemia was paired with same-day levels of endothelial biomarkers measured after each 24-hour period for three consecutive days. Endotheliopathy was assessed by measurement of Syndecan-1, Platelet Endothelial Cell Adhesion Molecule-1 (PECAM-1), and soluble thrombomodulin (sTM).

RESULTS

Of the included patients, a total 57.5% were males, median age was 71 yr (interquartile range [IQR], 63-79), and 24.6% had diabetes prior to admission. Median admission time was 5 d (IQR, 3-10). Time above range (TAR) greater than 13.9 mmol/L, but not TAR 10.0-13.9 mmol/L, was associated with increase in sTM (0.01 ng/mL per %-point increase in TAR, p = 0.049) and PECAM-1 (0.01 ng/mL per %-point increase, p = 0.007). Glycemic variability was associated with increases in sTM (0.24 ng/mL per mmol/L increase in sd, p = 0.001 and 0.03 ng/mL per %-point increase in coefficient of variation, p < 0.001). Hypoglycemia 3.0-3.9 mmol/L was associated with increases in sTM (3.0 ng/mL, p < 0.001) and PECAM-1 (1.54 ng/mL, p < 0.001).

CONCLUSIONS AND RELEVANCE

In acutely admitted adult ICU patients, hypoglycemia was associated with endotheliopathy regardless of preadmission diabetes status. Hyperglycemia and high glycemic variability were associated with endotheliopathy in patients without diabetes. This suggests different responses to acute dysglycemia in patients with and without diabetes and warrants further investigation in clinical trials.

Neutrophil-modulated Dicer expression in macrophages influences inflammation resolution

The precise molecular mechanisms through which neutrophils regulate macrophages in the progression and resolution of acute inflammation remain poorly understood. Here, we present new findings on the role of Dicer in regulating macrophage phenotypic transitions essential for proper inflammatory progression and resolution, influenced by neutrophils. Using a zymosan A (Zym A)-induced self-limited mouse peritonitis model, we observed that Dicer expression in macrophages was significantly reduced by neutrophil-derived IFN-γ during the progression phase, but gradually returned to normal levels during the resolution phase following the engulfment of apoptotic neutrophils. Our study on macrophage-specific Dicer1-depletion (Dicer1-CKO) mice demonstrated that inflammation in these mice was more severe during the progression phase, characterized by increased pro-inflammatory cytokines and enhanced neutrophil trafficking. Additionally, resolution was impaired in Dicer1-CKO mice, leading to the accumulation of uncleared apoptotic neutrophils. Specifically, the absence of Dicer in macrophages resulted in M1 polarization and heightened bactericidal activity, facilitating the progression of acute inflammation. Conversely, inducing Dicer expression promoted macrophage transition to M2 polarization, enhancing apoptotic cell clearance and expediting the resolution of inflammation. Our findings suggest that Dicer plays a central role in regulating the progression and resolution of acute inflammation, with implications for the treatment of inflammatory diseases.

The endothelium at the interface between tissues and Staphylococcus aureus in the bloodstream

SUMMARYStaphylococcus aureus is a major human pathogen. It can cause many types of infections, in particular bacteremia, which frequently leads to infective endocarditis, osteomyelitis, sepsis, and other debilitating diseases. The development of secondary infections is based on the bacterium's ability to associate with endothelial cells lining blood vessels. The success of endothelial colonization and infection by S. aureus relies on its ability to express a wide array of cell wall-anchored and secreted virulence factors. Establishment of endothelial infection by the pathogen is a multistep process involving adhesion, invasion, extravasation, and dissemination of the bacterium into surrounding tissues. The process is dependent on the type of endothelium in different organs (tissues) and pathogenetic potential of the individual strains. In this review, we report an update on the organization of the endothelium in the vessels, the structure and function of the virulence factors of S. aureus, and the several aspects of bacteria-endothelial cell interactions. After these sections, we will discuss recent advances in understanding the specific mechanisms of infections that develop in the heart, bone and joints, lung, and brain. Finally, we describe how neutrophils bind to endothelial cells, migrate to the site of infection to kill bacteria in the tissues, and how staphylococci counteract neutrophils' actions. Knowledge of the molecular details of S. aureus-endothelial cell interactions will promote the development of new therapeutic strategies and tools to combat this formidable pathogen.

Dynamic responses to rejection in the transplanted human heart revealed through spatial transcriptomics

Allograft rejection following solid-organ transplantation is a major cause of graft dysfunction and mortality. Current approaches to diagnosis rely on histology, which exhibits wide diagnostic variability and lacks access to molecular phenotypes that may stratify therapeutic response. Here, we leverage image-based spatial transcriptomics at sub-cellular resolution in longitudinal human cardiac biopsies to characterize transcriptional heterogeneity in 62 adult and pediatric heart transplant (HT) recipients during and following histologically-diagnosed rejection. Across 28 cell types, we identified significant differences in abundance in CD4 + and CD8 + T cells, fibroblasts, and endothelial cells across different biological classes of rejection (cellular, mixed, antibody-mediated). We observed a broad overlap in cellular transcriptional states across histologic rejection severity and biological class and significant heterogeneity within rejection severity grades that would qualify for immunomodulatory treatment. Individuals who had resolved rejection after therapy had a distinct transcriptomic profile relative to those with persistent rejection, including 216 genes across 6 cell types along pathways of inflammation, IL6-JAK-STAT3 signaling, IFNα/IFNγ response, and TNFα signaling. Spatial transcriptomics also identified genes linked to long-term prognostic outcomes post-HT. These results underscore importance of subtyping immunologic states during rejection to stratify immune-cardiac interactions following HT that are therapeutically relevant to short- and long-term rejection-related outcomes.

Prevention of tuberculosis in cynomolgus macaques by an attenuated Mycobacterium tuberculosis vaccine candidate

The need for novel vaccination strategies to control tuberculosis (TB) is underscored by the limited and variable efficacy of the currently licensed vaccine, Bacille Calmette-Guerin (BCG). SigH is critical for Mycobacterium tuberculosis (Mtb) to mitigate oxidative stress, and in its absence Mtb is unable to scavenge host oxidative/nitrosative bursts. The MtbΔsigH (ΔsigH) isogenic mutant induces signatures of the innate immunity in macrophages and protects rhesus macaques from a lethal Mtb challenge. To understand the immune mechanisms of protection via mucosal vaccination with ΔsigH, we employed the resistant cynomolgus macaque model; and our results show that ΔsigH vaccination significantly protects against lethal Mtb challenge in this species. ΔsigH-vaccinated macaques are devoid of granulomas and instead generate inducible bronchus associated lymphoid structures, and robust antigen-specific CD4+ and CD8+ T cell responses, driven by a hyper-immune, trained immunity-like phenotype in host macrophages with enhanced antigen presentation. Correlates of protection in ΔsigH-vaccinated macaques include gene signatures of T cell activation, IFNG production, including IFN-responsive, activated T cells, concomitant with IFNG production, and suppression of IDO+ Type I IFN-responsive macrophage recruitment. Thus, ΔsigH is a promising lead candidate for further development as an antitubercular vaccine.

Precise gene expression deconvolution in spatial transcriptomics with STged

Spatially resolved transcriptomics (SRT) has transformed tissue biology by linking gene expression profiles with spatial information. However, sequencing-based SRT methods aggregate signals from multiple cell types within capture locations ("spots"), masking cell-type-specific gene expression patterns. Traditional cell-type deconvolution methods estimate cell compositions within spots but fail to resolve cell-type-specific gene expression, limiting their ability to uncover critical biological processes such as cellular interactions and microenvironmental dynamics. Here, we present STged (spatial transcriptomic gene expression deconvolution), a novel computational framework that goes beyond traditional deconvolution by reconstructing cell-type-specific gene expression profiles from mixed spots. STged integrates graph-based spatial correlations and reference-derived gene signatures using a non-negative least-squares regression framework, achieving precise and biologically meaningful deconvolution. Comprehensive simulations show that STged consistently outperforms existing methods in accuracy and robustness. Applications to human pancreatic ductal adenocarcinoma and human squamous cell carcinoma datasets reveal its capacity to identify microenvironment-specific highly variable genes, reconstruct spatial cell-cell communication networks, and resolve tissue architecture at near-single-cell resolution. In mouse kidney tissues, STged uncovers dynamic spatial gene expression patterns and distinct gene programs, advancing our understanding of tissue heterogeneity and cellular dynamics.

Application of therapeutical nanoparticles with neutrophil membrane camouflaging for inflammatory plaques targeting against atherosclerosis

Atherosclerosis is the leading cause of cardiovascular disease and myocardial infarction. Precise and effective plaque targeting is a major objective for therapeutic outcomes throughout various stages of atherosclerosis. Inspired by the natural recruitment of neutrophils in atherosclerotic plaques, we fabricated a simvastatin (ST)-loaded and neutrophil membrane-cloaked nanoplatform (NNPST) for enhancing localized payload delivery and atherosclerosis management. The resulting NNPST mimicked neutrophil function and significantly decreased macrophage-mediated phagocytosis to prolong its own circulation time in the blood. Compared to pristine nanoparticles (NPST) without a membrane coating, NNPST achieved better plaque targeting in ApoE-/- mice, as indicated by neutrophils actively recruited in atherosclerotic lesions. The higher plaque homing with NNPST was monitored by dynamic fluorescence/magnetic resonance (MR) dual-modality imaging. The results further showed that NNPST efficiently prevented atherosclerosis development mainly by suppressing local inflammatory macrophages, and the percentage of plaques in the entire aortic area was reduced to 4.75 ± 1.48 % following NNPST treatment. A biosafety assessment indicated that the biomimetic NNPST induced no noticeable toxicity in the body. This approach of neutrophil membrane-camouflaged nanoparticles offers new opportunities to various therapeutic agents for on-demand delivery in neutrophil-involved inflammatory diseases.

Tension at the gate: sensing mechanical forces at the blood-brain barrier in health and disease

Microvascular brain endothelial cells tightly limit the entry of blood components and peripheral cells into the brain by forming the blood-brain barrier (BBB). The BBB is regulated by a cascade of mechanical and chemical signals including shear stress and elasticity of the adjacent endothelial basement membrane (BM). During physiological aging, but especially in neurological diseases including multiple sclerosis (MS), stroke, small vessel disease, and Alzheimer's disease (AD), the BBB is exposed to inflammation, rigidity changes of the BM, and disturbed cerebral blood flow (CBF). These altered forces lead to increased vascular permeability, reduced endothelial reactivity to vasoactive mediators, and promote leukocyte transmigration. Whereas the molecular players involved in leukocyte infiltration have been described in detail, the importance of mechanical signalling throughout this process has only recently been recognized. Here, we review relevant features of mechanical forces acting on the BBB under healthy and pathological conditions, as well as the endothelial mechanosensory elements detecting and responding to altered forces. We demonstrate the underlying complexity by focussing on the family of transient receptor potential (TRP) ion channels. A better understanding of these processes will provide insights into the pathogenesis of several neurological disorders and new potential leads for treatment.

Effects of Panax notoginseng saponins on alleviating low shear induced endothelial inflammation and thrombosis via Piezo1 signalling

ETHNOPHARMACOLOGICAL RELEVANCE

Panax notoginseng saponins (PNS) are the major effective components of Panax notoginseng (burk) F.H.Chen which is one of the classic promoting blood circulation herbs in traditional Chinese medicine. PNS is widely used in China for the treatment of cerebral ischemic stroke. Pathological low shear stress is a causal factor in endothelial inflammation and thrombosis. However, the mechanism of PNS against low shear related endothelial inflammation is still unclear.

AIM TO THE STUDY

This study aims to investigate the effects of PNS against endothelial inflammation induced by low shear stress and to explore the underlying mechanical and biological mechanisms.

MATERIALS AND METHODS

Mouse model of carotid partial ligation for inducing low endothelial shear stress was established, the pharmacodynamic effect and mechanism of PNS against endothelial inflammation induced by low shear stress through Piezo1 were explored. Yoda1-evoked Piezo1 activation and expression in human umbilical vein endothelial cells (HUVECs) were determined at static condition. Microfluidic channel systems were used to apply shear stress on HUVECs and Piezo1 siRNA HUVECs to determine PECAM-1, p-YAP and VCAM-1 expression. And platelet rich plasma (PRP) was introduced to low shear treated endothelial cells surface to observe the adhesion and activation by fluorescence imaging and flowcytometry.

RESULTS

PNS attenuated endothelial inflammation and improved blood flow in a reasonable dose response pattern in carotid partial ligation mouse model by influencing Piezo1 and PECAM-1 expression, while suppressing yes-associated protein (YAP) nuclear translocation. We found Piezo1 sensed abnormal shear stress and transduced these mechanical signals by different pathways in HUVECs, and PNS relieved endothelial inflammation induced by low shear stress through Piezo1. We also found Piezo1 signalling has interaction with PECAM-1 under low shear stress, which were involved in platelets adhesion to endothelial cells. Low shear stress increased YAP nuclear translocation and increased VCAM-1 expression in HUVECs which might activate platelets. PNS inhibited low shear induced Piezo1 and PECAM-1 expression and YAP nuclear translocation in HUVECs, furthermore inhibited platelet adhesion and activation on dysfunctional endothelial cells induced by low shear stress.

CONCLUSION

PNS ameliorated endothelial inflammation and thrombosis induced by low shear stress through modulation of the Piezo1 channel, PECAM-1 expression, and YAP nuclear translocation. PNS might serve as a potential therapeutic candidate for ameliorating endothelial inflammation induced by abnormal blood shear stress.

Left Ventricular Apical Aneurysm in a Dog-A Case Report

The cadaver of a 16-year-old mixed-breed male dog was presented to the Faculty of Veterinary Medicine of IULS, Romania, after having been euthanized in a private practice at the owner's request following acute cardio-respiratory failure. The necropsy revealed a left ventricular apical aneurysm with a bulging fibrous sac measuring about 0.7 cm/0.3 cm. The lesion involved all three structures of the cardiac wall, with mineralization areas and neovascularization. Immunohistochemistry showed strong positivity for desmin and weak positivity for CD-31 in the cardiac muscle fibers, positivity for α-sma in the smooth muscle cells of the vascular walls and positivity for vimentin in the cardiac stroma. MMP-2 and MMP-9 showed strong expression in the cardiomyocytes, whereas TIMP-1 showed positive immunoexpression only in the Eberth's lines. To the authors' knowledge, left ventricular apical aneurysm has only been reported once in dogs.

Elevated PD-L1 and PECAM-1 as Diagnostic Biomarkers of Acute Rejection in Lung Transplantation

Acute cellular rejection (ACR) frequently occurs following lung transplantation (LuTx) and represents a risk factor for the development of chronic lung allograft dysfunction (CLAD) as well as long-term survival. The histopathological diagnosis of ACR carries a burden of interobserver variability. The widespread utilization and cost-effectiveness of immunohistochemistry (IHC) was proven beneficial in diagnosing rejection in human kidney transplantations and LuTx rat models. However, its potential for ACR detection in patients remains unexplored. We analyzed surface markers (CD3, CD4, CD8, CD20, CD68, CD47, PD-1, PD-L1, and CD31/PECAM-1) on lung tissue cryobiopsy samples collected within 6 months post-LuTx from 60 LuTx recipients, 48 of whom were diagnosed with ACR. Additionally, serum samples from 51 patients were analyzed using a multiplex bead-based Luminex assay. The cytokines and markers included PD-L1, IL2, TNFα, IFNγ, and Granzyme B. We observed a significant increase in PD-L1 tissue expression within the rejection group, suggesting a concerted effort to suppress immune responses, especially those mediated by T-cells. Furthermore, we noted significant differences in PECAM-1 levels between ACR/non-ACR. Additionally, peripheral blood C-reactive-protein levels tended to be higher in the ACR group, while Luminex serum analyses did not reveal any significant differences between groups. In conclusion, our findings suggest the potential value of PECAM-1 and PD-L1 markers in diagnosing ACR.

Associations of Circulating Platelet Endothelial Cell Adhesion Molecule-1 Levels With Progression of Cerebral Small-Vessel Disease, Cognitive Decline, and Incident Dementia

BACKGROUND

The association between platelet endothelial cell adhesion molecule-1 (PECAM-1) with cerebral small-vessel disease and cognition in dementia-free subjects remains uninvestigated.

METHODS AND RESULTS

A prospective cohort of dementia-free subjects was recruited from memory clinics and followed up for 5 years. Annual neurocognitive assessments and twice-yearly brain magnetic resonance imaging scans were performed. Associations of baseline plasma PECAM-1 levels with cerebral small-vessel disease, cognitive decline (Montreal Cognitive Assessment scores and executive function Z scores), and incident dementia were evaluated. Of 213 subjects (aged 70.2±7.7 years, 51.2% men), median PECAM-1 levels were 0.790 (interquartile range, 0.645-0.955 ng/mL). Compared with the highest tertile, subjects within the lowest PECAM-1 tertile had greater cross-sectional white matter hyperintensity volume (β=4.84 [95% CI, 0.67-9.01]; P=0.023), age-related white matter change scores (β=1.39 [95% CI, 0.12-2.67]; P=0.033), and cerebral microbleeds (Adjusted risk ratio, 2.59 [95% CI, 1.19-5.62]; P=0.016). Of the 204 participants with follow-up data (median, 60.0 [interquartile range, 60.0-60.0] months), 24 (11.8%) developed incident dementia. Compared with the highest tertile, subjects within the lower tertiles of PECAM-1 had a higher risk of incident dementia (first tertile: adjusted hazard ratio [AHR], 4.52 [95% CI, 1.35-15.13]; P=0.024; second tertile: AHR, 3.28 [95% CI, 1.02-10.60]; P=0.047). The lowest PECAM-1 tertile was associated with greater progression of white matter hyperintensity volume (β=4.15 [95% CI, 0.06-8.24]; P=0.047), cerebral microbleeds (incident relative risk [IRR], 2.21 [95% CI, 1.05-4.65]; P=0.036), and decline in executive function (β=-0.45 [95% CI, -0.76 to -0.14]; P=0.004), and Montreal Cognitive Assessment (β=-1.32 [95% CI, -2.30 to -0.35]; P=0.008) scores.

CONCLUSIONS

In dementia-free subjects, lower circulating PECAM-1 levels are associated with greater cerebral small-vessel disease progression and cognitive decline, thus warranting future study as a potential therapeutic target.

Complement System and Adhesion Molecule Skirmishes in Fabry Disease: Insights into Pathogenesis and Disease Mechanisms

Fabry disease is a rare X-linked lysosomal storage disorder caused by mutations in the galactosidase alpha (GLA) gene, resulting in the accumulation of globotriaosylceramide (Gb3) and its deacetylated form, globotriaosylsphingosine (Lyso-Gb3) in various tissues and fluids throughout the body. This pathological accumulation triggers a cascade of processes involving immune dysregulation and complement system activation. Elevated levels of complement 3a (C3a), C5a, and their precursor C3 are observed in the plasma, serum, and tissues of patients with Fabry disease, correlating with significant endothelial cell abnormalities and vascular dysfunction. This review elucidates how the complement system, particularly through the activation of C3a and C5a, exacerbates disease pathology. The activation of these pathways leads to the upregulation of adhesion molecules, including vascular cell adhesion molecule 1 (VCAM1), intercellular adhesion molecule 1 (ICAM1), platelet and endothelial cell adhesion molecule 1 (PECAM1), and complement receptor 3 (CR3) on leukocytes and endothelial cells. This upregulation promotes the excessive recruitment of leukocytes, which in turn exacerbates disease pathology. Targeting complement components C3a, C5a, or their respective receptors, C3aR (C3a receptor) and C5aR1 (C5a receptor 1), could potentially reduce inflammation, mitigate tissue damage, and improve clinical outcomes for individuals with Fabry disease.

Sea Buckthorn Oil Promotes the PI3K-Akt-ERK Signaling Pathway and Macrophage M2 Polarization to Reduce Radiation-induced Skin Injury

In this work, we explored the role and mechanism of sea buckthorn oil in reducing radiation-induced skin damage. The radiation-induced rat skin injury model was established using strontium-90. Rats were treated with sea buckthorn oil twice a day postirradiation, and skin damage was observed at different times and evaluated using an injury score. Skin pathological changes were observed using hematoxylin and eosin (H&E) staining. Western blotting and immunohistochemistry were used to detect the expression of vascular growth and pathway proteins. ELISA was used to detect the secretion level of inflammatory factors. Immunohistochemistry was used to detect macrophage polarization marker proteins. We found that sea buckthorn oil can alleviate radiation-induced skin damage, accelerate skin vascular regeneration, and promote the up-regulation of vascular endothelial growth factor (VEGF) and its receptor (VEGFR). These results demonstrate the beneficial effects of sea buckthorn oil on radiation-induced skin damage. Furthermore, the levels of IL-1β and TNF-α in the sea buckthorn oil treatment group were significantly lower than those in the control group, while the levels of IL-4 and IL10 were significantly higher (P < 0.05). CD206 expression also increased in the sea buckthorn oil treatment group, while CD16 expression decreased compared to the control group (P < 0.05). Western blotting showed that PI3K, Akt and ERK expression increased in the sea buckthorn oil treatment group (P < 0.05). The beneficial effect of sea buckthorn oil in reducing the inflammatory response in irradiated rats was diminished when they were treated with PI3K inhibitor. We conclude that sea buckthorn oil may regulate macrophage M2 polarization by increasing the PI3K-Akt-ERK signaling pathway, thereby inhibiting the inflammatory response and promoting skin vascular regeneration to prevent and treat radiation-induced skin damage.

Biomarker analysis from the phase 2b randomized placebo-controlled trial of riociguat in early diffuse cutaneous systemic sclerosis

OBJECTIVE

To examine disease and target engagement biomarkers in the RISE-SSc trial of riociguat in early diffuse cutaneous systemic sclerosis and their potential to predict the response to treatment.

METHODS

Patients were randomized to riociguat (n = 60) or placebo (n = 61) for 52 weeks. Skin biopsies and plasma/serum samples were obtained at baseline and week 14. Plasma cyclic guanosine monophosphate (cGMP) was assessed using radio-immunoassay. α-Smooth muscle actin (αSMA) and skin thickness were determined by immunohistochemistry, mRNA markers of fibrosis by qRT-PCR in skin biopsies, and serum CXC motif chemokine ligand 4 (CXCL-4) and soluble platelet endothelial cell adhesion molecule-1 (sPECAM-1) by enzyme-linked immunosorbent assay.

RESULTS

By week 14, cGMP increased by 94 (78)% with riociguat and 10 (39)% with placebo (P < 0.001, riociguat vs placebo). Serum sPECAM-1 and CXCL-4 decreased with riociguat vs placebo (P = 0.004 and P = 0.008, respectively). There were no differences in skin collagen markers between the two groups. Higher baseline serum sPECAM-1 or the detection of αSMA-positive cells in baseline skin biopsies was associated with a larger reduction of modified Rodnan skin score from baseline at week 52 with riociguat vs placebo (interaction P-values 0.004 and 0.02, respectively).

CONCLUSION

Plasma cGMP increased with riociguat, suggesting engagement with the nitric oxide-soluble guanylate cyclase-cGMP pathway. Riociguat was associated with a significant reduction in sPECAM-1 (an angiogenic biomarker) vs placebo. Elevated sPECAM-1 and the presence of αSMA-positive skin cells may help to identify patients who could benefit from riociguat in terms of skin fibrosis.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT02283762.

Aging human abdominal subcutaneous white adipose tissue at single cell resolution

White adipose tissue (WAT) is a robust energy storage and endocrine organ critical for maintaining metabolic health as we age. Our aim was to identify cell-specific transcriptional aberrations that occur in WAT with aging. We leveraged full-length snRNA-Seq and histology to characterize the cellular landscape of human abdominal subcutaneous WAT in a prospective cohort of 10 younger (≤30 years) and 10 older individuals (≥65 years) balanced for sex and body mass index (BMI). The older group had greater cholesterol, very-low-density lipoprotein, triglycerides, thyroid stimulating hormone, and aspartate transaminase compared to the younger group (p < 0.05). We highlight that aging WAT is associated with adipocyte hypertrophy, increased proportions of lipid-associated macrophages and mast cells, an upregulation of immune responses linked to fibrosis in pre-adipocyte, adipocyte, and vascular populations, and highlight CXCL14 as a biomarker of these processes. We show that older WAT has elevated levels of senescence marker p16 in adipocytes and identify the adipocyte subpopulation driving this senescence profile. We confirm that these transcriptional and phenotypical changes occur without overt fibrosis and in older individuals that have comparable WAT insulin sensitivity to the younger individuals.

Human genital dendritic cell heterogeneity confers differential rapid response to HIV-1 exposure

Dendritic cells (DCs) play critical roles in HIV pathogenesis and require further investigation in the female genital tract, a main portal of entry for HIV infection. Here we characterized genital DC populations at the single cell level and how DC subsets respond to HIV immediately following exposure. We found that the genital CD11c+HLA-DR+ myeloid population contains three DC subsets (CD1c+ DC2s, CD14+ monocyte-derived DCs and CD14+CD1c+ DC3s) and two monocyte/macrophage populations with distinct functional and phenotypic properties during homeostasis. Following HIV exposure, the antiviral response was dominated by DCs' rapid secretory response, activation of non-classical inflammatory pathways and host restriction factors. Further, we uncovered subset-specific differences in anti-HIV responses. CD14+ DCs were the main population activated by HIV and mediated the secretory antimicrobial response, while CD1c+ DC2s activated inflammasome pathways and IFN responses. Identification of subset-specific responses to HIV immediately after exposure could aid targeted strategies to prevent HIV infection.

Comparative analysis of meningeal transcriptomes in birds: Potential pathways of resilience to repeated impacts

The meninges and associated vasculature (MAV) play a crucial role in maintaining cerebral integrity and homeostasis. Recent advances in transcriptomic analysis have illuminated the significance of the MAV in understanding the complex physiological interactions at the interface between the skull and the brain after exposure to mechanical stress. To investigate how physiological responses may confer resilience against repetitive mechanical stress, we performed the first transcriptomic analysis of avian MAV tissues using the Downy Woodpecker (Dryobates pubescens) and Tufted Titmouse (Baeolophus bicolor) as the comparison species. Our findings reveal divergences in gene expression profiles related to immune response, cellular stress management, and protein translation machinery. The male woodpeckers exhibit a tailored immune modulation strategy that potentially dampens neuroinflammation while preserving protective immunity. Overrepresented genes involved in cellular stress responses suggest enhanced mechanisms for mitigating damage and promoting repair. Additionally, the enrichment of translation-associated pathways hints at increased capacity for protein turnover and cellular remodeling vital for recovery. Our study not only fills a critical gap in avian neurobiology but also lays the groundwork for research in comparative neuroprotection.

Increased shedding of PECAM-1 associated with elevated serum MMP-14 levels as new blood indicators of dengue disease manifestation

OBJECTIVES

Host factors that regulate plasma leakage during severe dengue (SD) are under investigation. While PECAM-1 and MMP-14 have been reported to regulate vascular integrity, their role in dengue pathogenesis remains unexplored. This study aims to assess the association of soluble PECAM-1 and MMP-14 with dengue severity symptoms.

PATIENTS AND METHODS

Serum levels of PECAM-1 and MMP-14 were evaluated in dengue (N-25) comprising 10 severe dengue (SD) and 15 non-severe dengue, 10 other febrile illnesses along with healthy controls (N-10) using ELISA. Protein levels were assessed using in vitro models.

RESULTS

From febrile to critical phase, a significant increase in PECAM-1 (P≤0.01) & MMP-14 (P≤0.001) levels were observed in SD cases compared to non-severe or other controls. Serum levels of PECAM-1 and MMP 14 were found to be positively (P≤0.001) associated. Soluble PECAM-1 levels of severe defervescence showed a positive correlation (P≤0.001) with plasma leakage and an inverse relationship (P≤0.001) with platelet count. In vitro analysis revealed elevated expression of study proteins in endothelial cells activated with severe serum samples. To the best of our knowledge, this is the first report to explore PECAM-1 or MMP-14 dynamics and their association with dengue severity.

CONCLUSION

Higher shedding of sPECAM-1 accompanied with increased levels of MMP-14 is strongly associated with severe dengue. However, the exact role of serum PECAM-1 in disease prognosis requires further studies.

Boron substitution in silicate bioactive glass scaffolds to enhance bone differentiation and regeneration

Commercially available bioactive glasses (BAGs) are exclusively used in powder form, due to their tendency to crystallize. Silicate BAG 1393 was developed to allow fiber drawing and scaffold sintering, but its slow degradation limits its potential. To enable scaffold manufacturing while maintaining glass dissolution rate close to that of commercially available BAGs, the borosilicate glass 1393B20 was developed. This study investigates the potential of 1393B20 scaffolds to support bone regeneration and mineralization in vitro and in vivo, in comparison to silicate 1393. Both scaffolds supported human adipose stem cells proliferation, either in direct contact for the 1393, or mainly around for the 1393B20. Similarly, both BAGs induced osteogenesis and angiogenesis in vitro, with a better pro-angiogenic influence of the 1393B20. In addition, these scaffolds supported bone regeneration and osteoclast/osteoblast activity in vivo in critical-sized rat calvarial defect. Nevertheless, mineralization and collagen formation were significantly enhanced for the 1393B20, at 3-months post-implantation, assigned to faster and more complete dissolution of the scaffolds. Thus, 1393B20 demonstrates greater promise for bone tissue engineering certainly due to its time-controlled release of boron and silicon. STATEMENT OF SIGNIFICANCE: Bioactive glasses (BAGs) show great promise in bone tissue engineering as they effectively bond with bone tissue, fostering integration and regeneration. Silicate BAG 1393 was developed to allow fiber drawing and scaffold sintering, but its slow degradation limits its potential. To enable scaffold manufacturing while maintaining glass dissolution rate close to that of commercially available BAGs, the borosilicate glass 1393B20 was developed. Both BAGs induced osteogenesis and angiogenesis in vitro, with a better pro-angiogenic influence of the 1393B20. The presence of boron in the 1393B20 enhanced mineralization and collagen formation in vivo compared to 1393, probably due to its faster dissolution rate. Here, 1393B20 demonstrated greater promise for bone tissue engineering compared to the well-known 1393 BAG.

Nanoarchitectonic Engineering of Thermal-Responsive Magnetic Nanorobot Collectives for Intracranial Aneurysm Therapy

Stent-assisted coiling is a main treatment modality for intracranial aneurysms (IAs) in clinics, but critical challenges remain to be overcome, such as exogenous implant-induced stenosis and reliance on antiplatelet agents. Herein, an endovascular approach is reported for IA therapy without stent grafting or microcatheter shaping, enabled by active delivery of thrombin (Th) to target aneurysms using innovative phase-change material (PCM)-coated magnetite-thrombin (Fe3O4-Th@PCM) FTP nanorobots. The nanorobots are controlled by an integrated actuation system of dynamic torque-force hybrid magnetic fields. With robust intravascular navigation guided by real-time ultrasound imaging, nanorobotic collectives can effectively accumulate and retain in model aneurysms constructed in vivo, followed by controlled release of the encapsulated Th for rapid occlusion of the aneurysm upon melting the protective PCM (thermally responsive in a tunable manner) through focused magnetic hyperthermia. Complete and stable aneurysm embolization is confirmed by postoperative examination and 2-week postembolization follow-up using digital subtraction angiography (DSA), contrast-enhanced ultrasound (CEUS), and histological analysis. The safety of the embolization therapy is assessed through biocompatibility evaluation and histopathology assays. This strategy, seamlessly integrating secure drug packaging, agile magnetic actuation, and clinical interventional imaging, avoids possible exogenous implant rejection, circumvents cumbersome microcatheter shaping, and offers a promising option for IA therapy.

Circulating cell adhesion molecules in systemic sclerosis: a systematic review and meta-analysis

Introduction

Patients with systemic sclerosis (SSc) have an increased risk of endothelial dysfunction, atherosclerosis, and cardiovascular events compared to the general population. Therefore, the availability of robust circulating biomarkers of endothelial dysfunction and atherogenesis may facilitate early recognition and management of cardiovascular risk in SSc. We sought to address this issue by conducting a systematic review and meta-analysis of studies investigating various types of circulating cell adhesion molecules involved in endothelial dysfunction and atherogenesis (i.e., immunoglobulin-like vascular cell, VCAM-1, intercellular, ICAM-1, platelet endothelial cell, PECAM-1, neural cell, NCAM, Down syndrome cell, DSCAM, and endothelial cell-selective, ESAM, adhesion molecules, E-, L-, and P-selectin, integrins, and cadherins) in SSc patients and healthy controls.

Methods

We searched PubMed, Scopus, and Web of Science from inception to 1 May 2024. Risk of bias and certainty of evidence were assessed using validated tools.

Results

In 43 eligible studies, compared to controls, patients with SSc had significantly higher plasma or serum concentrations of ICAM-1 (standard mean difference, SMD=1.16, 95% CI 0.88 to 1.44, p<0.001; moderate certainty), VCAM-1 (SMD=1.09, 95% CI 0.72 to 1.46, p<0.001; moderate certainty), PECAM-1 (SMD=1.65, 95% CI 0.33 to 2.98, p=0.014; very low certainty), E-selectin (SMD=1.17, 95% CI 0.72 to 1.62, p<0.001; moderate certainty), and P-selectin (SMD=1.10, 95% CI 0.31 to 1.90, p=0.007; low certainty). There were no significant between-group differences in L-selectin concentrations (SMD=-0.35, 95% CI -1.03 to 0.32, p=0.31; very low certainty), whereas minimal/no evidence was available for cadherins, NCAM, DSCAM, ESAM, or integrins. Overall, no significant associations were observed between the effect size and various patient and study characteristics in meta-regression and subgroup analyses.

Discussion

The results of this systematic review and meta-analysis suggest that specific circulating cell adhesion molecules, i.e., ICAM-1, VCAM-1, PECAM-1, E-selectin, and P-selectin, can be helpful as biomarkers of endothelial dysfunction and atherogenesis in the assessment of cardiovascular risk in SSc patients.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42024549710.

Marginated Neutrophils in the Lungs Effectively Compete for Nanoparticles Targeted to the Endothelium, Serving as a Part of the Reticuloendothelial System

Nanomedicine has long pursued the goal of targeted delivery to specific organs and cell types but has yet to achieve this goal with the vast majority of targets. One rare example of success in this pursuit has been the 25+ years of studies targeting the lung endothelium using nanoparticles conjugated to antibodies against endothelial surface molecules. However, here we show that such "endothelial-targeted" nanocarriers also effectively target the lungs' numerous marginated neutrophils, which reside in the pulmonary capillaries and patrol for pathogens. We show that marginated neutrophils' uptake of many of these "endothelial-targeted" nanocarriers is on par with endothelial uptake. This generalizes across diverse nanomaterials and targeting moieties and was even found with physicochemical lung tropism (i.e., without targeting moieties). Further, we observed this in ex vivo human lungs and in vivo healthy mice, with an increase in marginated neutrophil uptake of nanoparticles caused by local or distant inflammation. These findings have implications for nanomedicine development for lung diseases. These data also suggest that marginated neutrophils, especially in the lungs, should be considered a major part of the reticuloendothelial system (RES), with a special role in clearing nanoparticles that adhere to the lumenal surfaces of blood vessels.

The impact of platelets on the metastatic potential of tumour cells

In cancer, activation of platelets by tumor cells is critical to disease progression. Development of precise antiplatelet targeting may improve outcomes from anticancer therapy. Alongside a distinct shift in functionality such as pro-metastatic and pro-coagulant properties, platelet production is often accelerated significantly early in carcinogenesis and the cancer-associated thrombocytosis increases the risk of metastasis formation and thromboembolic events. Tumor-activated platelets facilitate the proliferation of migrating tumor cells and shield them from immune surveillance and physical stress during circulation. Additionally, platelet-tumor cell interactions promote tumor cell intravasation, intravascular arrest, and extravasation through a repertoire of adhesion molecules, growth factors and angiogenic factors. Particularly, the presence of circulating tumor cell (CTC) clusters in association with platelets is a negative prognostic indicator. The contribution of platelets to the metastatic process is an area of intense investigation and this review provides an overview of the advances in understanding platelet-tumor cell interactions and their contribution to disease progression. Also, we review the potential of targeting platelets to interfere with the metastatic process.

Comparative single-cell transcriptional and proteomic atlas of clinical-grade injectable mesenchymal source tissues

Bone marrow aspirate concentrate (BMAC) and adipose-derived stromal vascular fraction (ADSVF) are the most marketed stem cell therapies to treat a variety of conditions in the general population and elite athletes. Both tissues have been used interchangeably clinically even though their detailed composition, heterogeneity, and mechanisms of action have neither been rigorously inventoried nor compared. This lack of information has prevented investigations into ideal dosages and has facilitated anecdata and misinformation. Here, we analyzed single-cell transcriptomes, proteomes, and flow cytometry profiles from paired clinical-grade BMAC and ADSVF. This comparative transcriptional atlas challenges the prevalent notion that there is one therapeutic cell type present in both tissues. We also provide data of surface markers that may enable isolation and investigation of cell (sub)populations. Furthermore, the proteome atlas highlights intertissue and interpatient heterogeneity of injected proteins with potentially regenerative or immunomodulatory capacities. An interactive webtool is available online.

PURION® processed human amnion chorion membrane allografts retain material and biological properties supportive of soft tissue repair

The reparative properties of amniotic membrane allografts are well-suited for a broad spectrum of specialties. Further enhancement of their utility can be achieved by designing to the needs of each application through the development of novel processing techniques and tissue configurations. As such, this study evaluated the material characteristics and biological properties of two PURION® processed amniotic membrane products, a lyophilized human amnion, intermediate layer, and chorion membrane (LHACM) and a dehydrated human amnion, chorion membrane (DHACM). LHACM is thicker; therefore, its handling properties are ideal for deep, soft tissue deficits; whereas DHACM is more similar to a film-like overlay and may be used for shallow defects or surgical on-lays. Characterization of the similarities and differences between LHACM and DHACM was conducted through a series of in vitro and in vivo studies relevant to the healing cascade. Compositional analysis was performed through histological staining along with assessment of barrier membrane properties through equilibrium dialysis. In vitro cellular response was assessed in fibroblasts and endothelial cells using cell proliferation, migration, and metabolic assays. The in vivo cellular response was assessed in an athymic nude mouse subcutaneous implantation model. The results indicated the PURION® process preserved the native membrane structure, nonviable cells and collagen distributed in the individual layers of both products. Although, LHACM is thicker than DHACM, a similar composition of growth factors, cytokines, chemokines and proteases is retained and consequently elicit comparable in vitro and in vivo cellular responses. In culture, both treatments behaved as potent mitogens, chemoattractants and stimulants, which translated to the promotion of cellular infiltration, neocollagen deposition and angiogenesis in a murine model. PURION® processed LHACM and DHACM differ in physical properties but possess similar in vitro and in vivo activities highlighting the impact of processing method on the versatility of clinical use of amniotic membrane allografts.

The dualistic role of Lyn tyrosine kinase in immune cell signaling: implications for systemic lupus erythematosus

Systemic lupus erythematosus (SLE, lupus) is a debilitating, multisystem autoimmune disease that can affect any organ in the body. The disease is characterized by circulating autoantibodies that accumulate in organs and tissues, which triggers an inflammatory response that can cause permanent damage leading to significant morbidity and mortality. Lyn, a member of the Src family of non-receptor protein tyrosine kinases, is highly implicated in SLE as remarkably both mice lacking Lyn or expressing a gain-of-function mutation in Lyn develop spontaneous lupus-like disease due to altered signaling in B lymphocytes and myeloid cells, suggesting its expression or activation state plays a critical role in maintaining tolerance. The past 30 years of research has begun to elucidate the role of Lyn in a duplicitous signaling network of activating and inhibitory immunoreceptors and related targets, including interactions with the interferon regulatory factor family in the toll-like receptor pathway. Gain-of-function mutations in Lyn have now been identified in human cases and like mouse models, cause severe systemic autoinflammation. Studies of Lyn in SLE patients have presented mixed findings, which may reflect the heterogeneity of disease processes in SLE, with impairment or enhancement in Lyn function affecting subsets of SLE patients that may be a means of stratification. In this review, we present an overview of the phosphorylation and protein-binding targets of Lyn in B lymphocytes and myeloid cells, highlighting the structural domains of the protein that are involved in its function, and provide an update on studies of Lyn in SLE patients.

Single-cell RNA sequencing analysis of vestibular schwannoma reveals functionally distinct macrophage subsets

BACKGROUND

Vestibular schwannomas (VSs) remain a challenge due to their anatomical location and propensity to growth. Macrophages are present in VS but their roles in VS pathogenesis remains unknown.

OBJECTIVES

The objective was to assess phenotypic and functional profile of macrophages in VS with single-cell RNA sequencing (scRNAseq).

METHODS

scRNAseq was carried out in three VS samples to examine characteristics of macrophages in the tumour. RT-qPCR was carried out on 10 VS samples for CD14, CD68 and CD163 and a panel of macrophage-associated molecules.

RESULTS

scRNAseq revealed macrophages to be a major constituent of VS microenvironment with three distinct subclusters based on gene expression. The subclusters were also defined by expression of CD163, CD68 and IL-1β. AREG and PLAUR were expressed in the CD68+CD163+IL-1β+ subcluster, PLCG2 and NCKAP5 were expressed in CD68+CD163+IL-1β- subcluster and AUTS2 and SPP1 were expressed in the CD68+CD163-IL-1β+ subcluster. RT-qPCR showed expression of several macrophage markers in VS of which CD14, ALOX15, Interleukin-1β, INHBA and Colony Stimulating Factor-1R were found to have a high correlation with tumour volume.

CONCLUSIONS

Macrophages form an important component of VS stroma. scRNAseq reveals three distinct subsets of macrophages in the VS tissue which may have differing roles in the pathogenesis of VS.

An ADSC-loaded dermal regeneration template promotes full-thickness wound healing

Introduction

Full-thickness wounds lead to delayed wound healing and scarring. Adipose-derived stem cell (ADSC) grafting promotes wound healing and minimizes scarring, but the low efficiency of grafting has been a challenge. We hypothesized that loading ADSCs onto a clinically widely used dermal regeneration template (DRT) would improve the efficacy of ADSC grafting and promote full-thickness wound healing.

Methods

ADSCs from human adipose tissue were isolated, expanded, and labeled with a cell tracker. Labeled ADSCs were loaded onto the DRT. The viability, the location of ADSCs on the DRT, and the abundance of ADSCs in the wound area were confirmed using CCK8 and fluorescence microscopy. Full-thickness wounds were created on Bama minipigs, which were applied with sham, ADSC, DRT, and ADSC-DRT. Wounds from the four groups were collected at the indicated time and histological analysis was performed. RNA-seq analysis was also conducted to identify transcriptional differences among the four groups. The identified genes by RNA-seq were verified by qPCR. Immunohistochemistry and western blotting were used to assess collagen deposition. In vitro, the supernatant of ADSCs was used to culture fibroblasts to investigate the effect of ADSCs on fibroblast transformation into myofibroblasts.

Results

ADSCs were successfully isolated, marked, and loaded onto the DRT. The abundance of ADSCs in the wound area was significantly greater in the ADSC-DRT group than in the ADSC group. Moreover, the ADSC-DRT group exhibited better wound healing with improved re-epithelialization and denser collagen deposition than the other three groups. The RNA-seq results suggested that the application of the integrated ADSC-DRT system resulted in the differential expression of genes mainly associated with extracellular matrix remodeling. In vivo, wounds from the ADSC-DRT group exhibited an earlier increase in type III collagen deposition and alleviated scar formation. ADSCs inhibited the transformation of fibroblasts into myofibroblasts, along with increased levels of CTGF, FGF, and HGF in the supernatant of ADSCs. Wounds from the ADSC-DRT group had up-regulated expressions of CTGF, HGF, FGF, and MMP3.

Conclusion

The integral of ADSC-DRT increased the efficacy of ADSC grafting, and promoted full-thickness wound healing with better extracellular matrix remodeling and alleviated scar formation.

Pre-Incisional and Multiple Intradermal Injection of N-Acetylcysteine Slightly Improves Incisional Wound Healing in an Animal Model

The objective of this study was to investigate if delivering multiple doses of N-acetylcysteine (NAC) post-surgery in addition to pre-incisional administration significantly impacts the wound healing process in a rat model. Full-thickness skin incisions were carried out on the dorsum of 24 Sprague-Dawley rats in six locations. Fifteen minutes prior to the incision, half of the sites were treated with a control solution, with the wounds on the contralateral side treated with solutions containing 0.015%, 0.03% and 0.045% of NAC. In the case of the NAC treated group, further injections were given every 8 h for three days. On days 3, 7, 14 and 60 post-op, rats were sacrificed to gather material for the histological analysis, which included histomorphometry, collagen fiber organization analysis, immunohistochemistry and Abramov scale scoring. It was determined that scars treated with 0.015% NAC had significantly lower reepithelization than the control at day 60 post-op (p = 0.0018). Scars treated with 0.045% NAC had a significantly lower collagen fiber variance compared to 0.015% NAC at day 14 post-op (p = 0.02 and p = 0.04) and a lower mean scar width than the control at day 60 post-op (p = 0.0354 and p = 0.0224). No significant differences in the recruitment of immune cells and histological parameters were found. The results point to a limited efficacy of multiple NAC injections post-surgery in wound healing.

Exploring the Relevance of Disulfidptosis to the Pathophysiology of Ulcerative Colitis by Bioinformatics Analysis

Background

Ulcerative colitis (UC) is a nonspecific inflammatory disease confined to the intestinal mucosa and submucosa, and its prevalence significantly increases each year. Disulfidptosis is a recently discovered new form of cell death that has been suggested to be involved in multiple diseases. The aim of this study was to explore the relevance of disulfidptosis in UC.

Methods

First, the UC datasets were downloaded from the Gene Expression Omnibus (GEO) database, and UC samples were typed based on upregulated disulfidptosis-related genes (DRGs). Then, weighted gene co-expression network analysis (WGCNA) was performed on the datasets and molecular subtypes of UC, respectively, to obtain candidate signature genes. After validation of the validation set and qRT-PCR, we constructed a nomogram model by signature genes to predict the risk of UC. Finally, single-cell sequencing analysis was used to study the heterogeneity of UC and to demonstrate the expression of DRGs and signature genes at the single-cell level.

Results

A total of 7 DRGs were significantly upregulated in the expression profiles of UC, and 180 UC samples were divided into two subtypes based on these DRGs. Five candidate signature genes were obtained by intersecting two key gene modules selected by WGCNA. After evaluation, four signature genes with diagnostic relevance (COL4A1, PRRX1, NNMT, and PECAM1) were eventually identified. The nomogram model showed excellent prediction ability. Finally, in the single-cell analysis, there were eight cell types (including B cells, T cells, monocyte, smooth muscle cells, epithelial cells, neutrophil, endothelial cells and NK cells) were identified. The signature genes were significantly expressed mainly in endothelial cells and smooth muscle cells.

Conclusion

In this study, subtypes related to disulfidptosis were identified, and single-cell analysis was performed to understand the pathogenesis of UC from a new perspective. Four signature genes were screened and a prediction model with high accuracy was established. This provides novel insights for early diagnosis and therapeutic targets in UC.

Multifaceted roles of lymphatic and blood endothelial cells in the tumor microenvironment of hepatocellular carcinoma: A comprehensive review

The tumor microenvironment is a complex network of cells, extracellular matrix, and signaling molecules that plays a critical role in tumor progression and metastasis. Lymphatic and blood vessels are major routes for solid tumor metastasis and essential parts of tumor drainage conduits. However, recent studies have shown that lymphatic endothelial cells (LECs) and blood endothelial cells (BECs) also play multifaceted roles in the tumor microenvironment beyond their structural functions, particularly in hepatocellular carcinoma (HCC). This comprehensive review summarizes the diverse roles played by LECs and BECs in HCC, including their involvement in angiogenesis, immune modulation, lymphangiogenesis, and metastasis. By providing a detailed account of the complex interplay between LECs, BECs, and tumor cells, this review aims to shed light on future research directions regarding the immune regulatory function of LECs and potential therapeutic targets for HCC.

Myocardial B cells have specific gene expression and predicted interactions in dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy

Introduction

Growing evidence from animal models indicates that the myocardium hosts a population of B cells that play a role in the development of cardiomyopathy. However, there is minimal data on human myocardial B cells in the context of cardiomyopathy.

Methods

We integrated single-cell and single-nuclei datasets from 45 healthy human hearts, 70 hearts with dilated cardiomyopathy (DCM), and 8 hearts with arrhythmogenic right ventricular cardiomyopathy (ARVC). Interactions between B cells and other cell types were investigated using the CellChat Package. Differential gene expression analysis comparing B cells across conditions was performed using DESeq2. Pathway analysis was performed using Ingenuity, KEGG, and GO pathways analysis.

Results

We identified 1,100 B cells, including naive B cells and plasma cells. Cells showed an extensive network of interactions within the healthy myocardium that included outgoing signaling to macrophages, T cells, endothelial cells, and pericytes, and incoming signaling from endothelial cells, pericytes, and fibroblasts. This niche relied on ECM-receptor, contact, and paracrine interactions; and changed significantly in the context of cardiomyopathy, displaying disease-specific features. Differential gene expression analysis showed that in the context of DCM both naive and plasma B cells upregulated several pathways related to immune activation, including upregulation of oxidative phosphorylation, upregulation of leukocyte extravasation, and, in naive B cells, antigen presentation.

Discussion

The human myocardium contains naive B cells and plasma cells, integrated into a diverse and dynamic niche that has distinctive features in healthy, DCM, and ARVC. Naive myocardial-associated B cells likely contribute to the pathogenesis of human DCM.

The Association between Circulating Cytokines and Body Composition in Frail Patients with Cardiovascular Disease

The burden of cardiovascular disease and the percentage of frail patients in the aging population will increase. This study aims to assess the circulating levels of several cytokines in frail patients. This is an ancillary analysis of the FRAPICA trial. The ratio of men/women changed from robust through frail groups from 3:1 to 1:2. The groups are comparable in terms of age and body measurements analysis (weight, height, and BMI), yet the frail patients have significantly reduced fat-free mass, and more often have been diagnosed with diabetes. Frail patients have higher fibroblast growth factor basic (FGF basic) and follistatin levels (borderline significance). In multiple linear regression modeling of fat-free mass, we identified FGF basic, osteopontin, stem cell factor, soluble suppression of tumorigenicity 2, soluble epidermal growth factor receptor, soluble human epidermal growth factor receptor 2, follistatin, prolactin, soluble interleukin 6 receptor alfa, platelet endothelial cell adhesion molecule 1, soluble vascular endothelial cell growth factor receptor 1, leptin, soluble angiopoietin/tyrosine kinase 2, and granulocyte colony-stimulating factor. We have identified a few cytokines that correlate with fat-free mass, a hallmark of frailty. They comprise the kinins implicated in bone and muscle metabolism, fibrosis, vascular wall function, inflammation, endocrine function, or regulation of bone marrow integrity.

Branched Channels in Porous β-Tricalcium Phosphate Scaffold Promote Vascularization

Rapid and efficient vascularization is still considerably challenging for a porous β-tricalcium phosphate (β-TCP) scaffold to achieve. To overcome this challenge, branched channels were created in the porous β-TCP scaffold by using 3D printing and a template-casting method to facilitate the instant flow of blood supply. Human bone mesenchymal stem cells (hBMSCs) and human umbilical vein endothelial cells (HUVECs) were seeded in the channeled porous scaffolds and characterized through a double-stranded DNA (dsDNA) assay, alkaline phosphatase (ALP) assay, and cell migration. Channeled porous β-TCP scaffolds were then implanted in the subcutaneous pockets of mice. Histological staining and immunohistochemical staining on vascularization and bone-related markers were carried out on the embedded paraffin sections. Results from in vitro experiments showed that branched channels significantly promoted HUVECs' infiltration, migration, proliferation, and angiogenesis, and also promoted the proliferation and osteogenesis differentiation of hBMSCs. In vivo implantation results showed that, in the early stage after implantation, cells significantly migrated into branched channeled scaffolds. More matured blood vessels formed in the branched channeled scaffolds compared to that in nonchanneled and straight channeled scaffolds. Beside promoting vascularization, the branched channels also stimulated the infiltration of bone-related cells into the scaffolds. These results suggested that the geometric design of branched channels in the porous β-TCP scaffold promoted rapid vascularization and potentially stimulated bone cells recruitment.

Pathophysiology of chikungunya virus infection associated with fatal outcomes

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes acute, subacute, and chronic human arthritogenic diseases and, in rare instances, can lead to neurological complications and death. Here, we combined epidemiological, virological, histopathological, cytokine, molecular dynamics, metabolomic, proteomic, and genomic analyses to investigate viral and host factors that contribute to chikungunya-associated (CHIK) death. Our results indicate that CHIK deaths are associated with multi-organ infection, central nervous system damage, and elevated serum levels of pro-inflammatory cytokines and chemokines compared with survivors. The histopathologic, metabolite, and proteomic signatures of CHIK deaths reveal hemodynamic disorders and dysregulated immune responses. The CHIKV East-Central-South-African lineage infecting our study population causes both fatal and survival cases. Additionally, CHIKV infection impairs the integrity of the blood-brain barrier, as evidenced by an increase in permeability and altered tight junction protein expression. Overall, our findings improve the understanding of CHIK pathophysiology and the causes of fatal infections.

Single-cell 'omic profiles of human aortic endothelial cells in vitro and human atherosclerotic lesions ex vivo reveal heterogeneity of endothelial subtype and response to activating perturbations

Heterogeneity in endothelial cell (EC) sub-phenotypes is becoming increasingly appreciated in atherosclerosis progression. Still, studies quantifying EC heterogeneity across whole transcriptomes and epigenomes in both in vitro and in vivo models are lacking. Multiomic profiling concurrently measuring transcriptomes and accessible chromatin in the same single cells was performed on six distinct primary cultures of human aortic ECs (HAECs) exposed to activating environments characteristic of the atherosclerotic microenvironment in vitro. Meta-analysis of single-cell transcriptomes across 17 human ex vivo arterial specimens was performed and two computational approaches quantitatively evaluated the similarity in molecular profiles between heterogeneous in vitro and ex vivo cell profiles. HAEC cultures were reproducibly populated by four major clusters with distinct pathway enrichment profiles and modest heterogeneous responses: EC1-angiogenic, EC2-proliferative, EC3-activated/mesenchymal-like, and EC4-mesenchymal. Quantitative comparisons between in vitro and ex vivo transcriptomes confirmed EC1 and EC2 as most canonically EC-like, and EC4 as most mesenchymal with minimal effects elicited by siERG and IL1B. Lastly, accessible chromatin regions unique to EC2 and EC4 were most enriched for coronary artery disease (CAD)-associated single-nucleotide polymorphisms from Genome Wide Association Studies (GWAS), suggesting that these cell phenotypes harbor CAD-modulating mechanisms. Primary EC cultures contain markedly heterogeneous cell subtypes defined by their molecular profiles. Surprisingly, the perturbations used here only modestly shifted cells between subpopulations, suggesting relatively stable molecular phenotypes in culture. Identifying consistently heterogeneous EC subpopulations between in vitro and ex vivo models should pave the way for improving in vitro systems while enabling the mechanisms governing heterogeneous cell state decisions.

Hemopexin reverses activation of lung eIF2α and decreases mitochondrial injury in chlorine-exposed mice

We assessed the mechanisms by which nonencapsulated heme, released in the plasma of mice after exposure to chlorine (Cl2) gas, resulted in the initiation and propagation of acute lung injury. We exposed adult male and female C57BL/6 mice to Cl2 (500 ppm for 30 min), returned them to room air, and injected them intramuscularly with either human hemopexin (hHPX; 5 µg/g BW in 50-µL saline) or vehicle at 1 h post-exposure. Upon return to room air, Cl2-exposed mice, injected with vehicle, developed respiratory acidosis, increased concentrations of plasma proteins in the alveolar space, lung mitochondrial DNA injury, increased levels of free plasma heme, and major alterations of their lung proteome. hHPX injection mice mitigated the onset and development of lung and mitochondrial injury and the increase of plasma heme, reversed the Cl2-induced changes in 83 of 237 proteins in the lung proteome at 24 h post-exposure, and improved survival at 15 days post-exposure. Systems biology analysis of the lung global proteomics data showed that hHPX reversed changes in a number of key pathways including elF2 signaling, verified by Western blotting measurements. Recombinant human hemopexin, generated in tobacco plants, injected at 1 h post-Cl2 exposure, was equally effective in reversing acute lung and mtDNA injury. The results of this study offer new insights as to the mechanisms by which exposure to Cl2 results in acute lung injury and the therapeutic effects of hemopexin.NEW & NOTEWORTHY Herein, we demonstrate that exposure of mice to chlorine gas causes significant changes in the lung proteome 24 h post-exposure. Systems biology analysis of the proteomic data is consistent with damage to mitochondria and activation of eIF2, the master regulator of transcription and protein translation. Post-exposure injection of hemopexin, which scavenges free heme, attenuated mtDNA injury, eIF2α phosphorylation, decreased lung injury, and increased survival.

Innate Immune Dysfunction and Neuroinflammation in Autism Spectrum Disorder (ASD)

Autism spectrum disorder (ASD) is a highly heterogeneous neurodevelopmental disorder characterized by communication and social behavior deficits. The presence of restricted and repetitive behaviors often accompanies these deficits, and these characteristics can range from mild to severe. The past several decades have seen a significant rise in the prevalence of ASD. The etiology of ASD remains unknown; however, genetic and environmental risk factors play a role. Multiple hypotheses converge to suggest that neuroinflammation, or at least the interaction between immune and neural systems, may be involved in the etiology of some ASD cases or groups. Repeated evidence of innate immune dysfunction has been seen in ASD, often associated with worsening behaviors. This evidence includes data from circulating myeloid cells and brain resident macrophages/microglia in both human and animal models. This comprehensive review presents recent findings of innate immune dysfunction in ASD, including aberrant innate cellular function, evidence of neuroinflammation, and microglia activation. Appeared originally in Brain Behav Immun 2023; 108:245-254.

A systematic review and meta-analysis of circulating adhesion molecules in rheumatoid arthritis

BACKGROUND

The availability of robust biomarkers of endothelial activation might enhance the identification of subclinical atherosclerosis in rheumatoid arthritis (RA). We investigated this issue by conducting a systematic review and meta-analysis of cell adhesion molecules in RA patients.

METHODS

We searched electronic databases from inception to 31 July 2023 for case-control studies assessing the circulating concentrations of immunoglobulin-like adhesion molecules (vascular cell, VCAM-1, intercellular, ICAM-1, and platelet endothelial cell, PECAM-1, adhesion molecule-1) and selectins (E, L, and P selectin) in RA patients and healthy controls. Risk of bias and certainty of evidence were assessed using the JBI checklist and GRADE, respectively.

RESULTS

In 39 studies, compared to controls, RA patients had significantly higher concentrations of ICAM-1 (standard mean difference, SMD = 0.81, 95% CI 0.62-1.00, p < 0.001; I2 = 83.0%, p < 0.001), VCAM-1 (SMD = 1.17, 95% CI 0.73-1.61, p < 0.001; I2 = 95.8%, p < 0.001), PECAM-1 (SMD = 0.82, 95% CI 0.57-1.08, p < 0.001; I2 = 0.0%, p = 0.90), E-selectin (SMD = 0.64, 95% CI 0.42-0.86, p < 0.001; I2 = 75.0%, p < 0.001), and P-selectin (SMD = 1.06, 95% CI 0.50-1.60, p < 0.001; I2 = 84.8%, p < 0.001), but not L-selectin. In meta-regression and subgroup analysis, significant associations were observed between the effect size and use of glucocorticoids (ICAM-1), erythrocyte sedimentation rate (VCAM-1), study continent (VCAM-1, E-selectin, and P-selectin), and matrix assessed (P-selectin).

CONCLUSIONS

The results of our study support a significant role of cell adhesion molecules in mediating the interplay between RA and atherosclerosis. Further studies are warranted to determine whether the routine use of these biomarkers can facilitate the detection and management of early atherosclerosis in this patient group. PROSPERO Registration Number: CRD42023466662.

Tissue-resident macrophages specifically express Lactotransferrin and Vegfc during ear pinna regeneration in spiny mice

The details of how macrophages control different healing trajectories (regeneration vs. scar formation) remain poorly defined. Spiny mice (Acomys spp.) can regenerate external ear pinnae tissue, whereas lab mice (Mus musculus) form scar tissue in response to an identical injury. Here, we used this dual species system to dissect macrophage phenotypes between healing modes. We identified secreted factors from activated Acomys macrophages that induce a pro-regenerative phenotype in fibroblasts from both species. Transcriptional profiling of Acomys macrophages and subsequent in vitro tests identified VEGFC, PDGFA, and Lactotransferrin (LTF) as potential pro-regenerative modulators. Examining macrophages in vivo, we found that Acomys-resident macrophages secreted VEGFC and LTF, whereas Mus macrophages do not. Lastly, we demonstrate the requirement for VEGFC during regeneration and find that interrupting lymphangiogenesis delays blastema and new tissue formation. Together, our results demonstrate that cell-autonomous mechanisms govern how macrophages react to the same stimuli to differentially produce factors that facilitate regeneration.

Resident Synovial Macrophages in Synovial Fluid: Implications for Immunoregulation in Infectious and Inflammatory Arthritis

Objectives

Resident synovial macrophages (RSM) provide immune sequestration of the joint space and are likely involved in initiation and perpetuation of the joint-specific immune response. We sought to identify RSM in synovial fluid (SF) and demonstrate migratory ability, in additional to functional changes that may perpetuate a chronic inflammatory response within joint spaces.

Methods

We recruited human patients presenting with undifferentiated arthritis in multiple clinical settings. We used flow cytometry to identify mononuclear cells in peripheral blood and SF. We used a novel transwell migration assay with human ex-vivo synovium obtained intra-operatively to validate flow cytometry findings. We used single cell RNA-sequencing (scRNA-seq) to further identify macrophage/monocyte subsets. ELISA was used to evaluate the bone-resorption potential of SF.

Results

We were able to identify a rare population of CD14dim, OPG+, ZO-1+ cells consistent with RSM in SF via flow cytometry. These cells were relatively enriched in the SF during infectious processes, but absolutely decreased compared to healthy controls. Similar putative RSM were identified using ex vivo migration assays when MCP-1 and LPS were used as migratory stimulus. scRNA-seq revealed a population consistent with RSM transcriptionally related to CD56+ cytotoxic dendritic cells and IDO+ M2 macrophages.

Conclusion

We identified a rare cell population consistent with RSM, indicating these cells are likely migratory and able to initiate or coordinate both acute (septic) or chronic (autoimmune or inflammatory) arthritis. RSM analysis via scRNA-seq indicated these cells are M2 skewed, capable of antigen presentation, and have consistent functions in both septic and inflammatory arthritis.

The pathophysiological role of circulating adhesion molecules in schizophrenia: A systematic review and meta-analysis

BACKGROUND

Increasing evidence suggests an association between schizophrenia and atherosclerosis. We conducted a systematic review and meta-analysis of cell adhesion molecules, critically involved in early atherosclerosis, in schizophrenia.

METHODS

We searched electronic databases from inception to 11 November 2023 for case-control studies assessing vascular cell, VCAM-1, intercellular, ICAM-1, platelet endothelial cell, PECAM-1, neural cell, NCAM, and Down syndrome cell, DSCAM, adhesion molecules, selectins (E-, L-, and P-selectin), integrins, and cadherins in patients with schizophrenia and healthy controls. Risk of bias and certainty of evidence were assessed using the JBI checklist and GRADE, respectively.

RESULTS

In 19 eligible studies, there were non-significant between-group differences in the concentrations of cell adhesion molecules, barring higher P-selectin in patients with schizophrenia (standard mean difference, SMD = 2.05, 95 % CI 0.72 to 3.38, p = 0.003; I2 = 97.2 %, p<0.001; very low certainty of evidence). Limited or no information was available regarding PECAM-1, DSCAM, ESAM, integrins, and cadherins. In meta-regression and subgroup analysis, there were significant associations between the SMD of ICAM-1 and matrix used (plasma or serum) and pharmacological treatment of schizophrenia, and between the SMD of VCAM-1 and pharmacological treatment, but not with other study and patient characteristics.

CONCLUSIONS

The results of our systematic review and meta-analysis do not support a significant role of immunoglobulin-like adhesion molecules, selectins, integrins, or cadherins in mediating the associations between schizophrenia, atherosclerosis, and cardiovascular disease. Further studies are warranted to investigate these associations in patients with different cardiovascular risk and the effects of antipsychotic treatments on cell adhesion molecules and surrogate markers of atherosclerosis (PROSPERO registration number: CRD42023463916).

Nitric oxide releasing novel amino acid-derived polymeric nanotherapeutic with anti-inflammatory properties for rapid wound tissue regeneration

Endogenous gasotransmitter nitric oxide (NO) is a central signalling molecule that modulates wound healing by maintaining homeostasis, collagen formation, wound contraction, anti-microbial action and accelerating tissue regeneration. The optimum delivery of NO using nanoparticles (NPs) is clinically challenging; hence, it is drawing significant attention in wound healing. Herein, a novel polymeric nanoplatform loaded with sodium nitroprusside (SP) NPs was prepared and used for wound healing to obtain the sustained release of NO in therapeutic quantities. SP NPs-induced excellent proliferation (∼300%) of mouse fibroblast (L929) cells was observed. With an increase in the SP NPs dose at 200 μg mL-1 concentration, a 200% upsurge in proliferation was observed along with enhanced migration, and only 17.09 h were required to fill the 50% gap compared to 37.85 h required by the control group. Further, SP NPs showed an insignificant impact on the coagulation cascade, revealing safe wound-healing treatment when tested in isolated rat RBCs. Additionally, SP NPs exhibited excellent angiogenic activity at a 10 μg mL-1 dose. Moreover, the formulated SP nanoformulation is non-irritant, non-toxic, and does not produce any skin sensitivity reaction on the rat's skin. Further, an in vivo wound healing study revealed that within 11 days of treatment with SP nanoformulation, 99.2 ± 1.0% of the wound was closed, while in the control group, only 45.5 ± 3.8% was repaired. These results indicate that owing to sustained NO release, the SP NP and SP nanoformulations are paramount with enormous clinical potential for the regeneration of wound tissues.

Single cell 'omic profiles of human aortic endothelial cells in vitro and human atherosclerotic lesions ex vivo reveals heterogeneity of endothelial subtype and response to activating perturbations

Objective

Endothelial cells (ECs), macrophages, and vascular smooth muscle cells (VSMCs) are major cell types in atherosclerosis progression, and heterogeneity in EC sub-phenotypes are becoming increasingly appreciated. Still, studies quantifying EC heterogeneity across whole transcriptomes and epigenomes in both in vitro and in vivo models are lacking.

Approach and Results

To create an in vitro dataset to study human EC heterogeneity, multiomic profiling concurrently measuring transcriptomes and accessible chromatin in the same single cells was performed on six distinct primary cultures of human aortic ECs (HAECs). To model pro-inflammatory and activating environments characteristic of the atherosclerotic microenvironment in vitro, HAECs from at least three donors were exposed to three distinct perturbations with their respective controls: transforming growth factor beta-2 (TGFB2), interleukin-1 beta (IL1B), and siRNA-mediated knock-down of the endothelial transcription factor ERG (siERG). To form a comprehensive in vivo/ex vivo dataset of human atherosclerotic cell types, meta-analysis of single cell transcriptomes across 17 human arterial specimens was performed. Two computational approaches quantitatively evaluated the similarity in molecular profiles between heterogeneous in vitro and in vivo cell profiles. HAEC cultures were reproducibly populated by 4 major clusters with distinct pathway enrichment profiles: EC1-angiogenic, EC2-proliferative, EC3-activated/mesenchymal-like, and EC4-mesenchymal. Exposure to siERG, IL1B or TGFB2 elicited mostly distinct transcriptional and accessible chromatin responses. EC1 and EC2, the most canonically 'healthy' EC populations, were affected predominantly by siERG; the activated cluster EC3 was most responsive to IL1B; and the mesenchymal population EC4 was most affected by TGFB2. Quantitative comparisons between in vitro and in vivo transcriptomes confirmed EC1 and EC2 as most canonically EC-like, and EC4 as most mesenchymal with minimal effects elicited by siERG and IL1B. Lastly, accessible chromatin regions unique to EC2 and EC4 were most enriched for coronary artery disease (CAD)-associated SNPs from GWAS, suggesting these cell phenotypes harbor CAD-modulating mechanisms.

Conclusion

Primary EC cultures contain markedly heterogeneous cell subtypes defined by their molecular profiles. Surprisingly, the perturbations used here, which have been reported by others to be involved in the pathogenesis of atherosclerosis as well as induce endothelial-to-mesenchymal transition (EndMT), only modestly shifted cells between subpopulations, suggesting relatively stable molecular phenotypes in culture. Identifying consistently heterogeneous EC subpopulations between in vitro and in vivo models should pave the way for improving in vitro systems while enabling the mechanisms governing heterogeneous cell state decisions.

Myocardial B cells have specific gene expression and predicted interactions in Dilated Cardiomyopathy and Arrhythmogenic Right Ventricular Cardiomyopathy

Introduction

Growing evidence from animal models indicates that the myocardium hosts a population of B cells that play a role in the development of cardiomyopathy. However, there is minimal data on human myocardial B cells in the context of cardiomyopathy.

Methods

We integrated single-cell and single-nuclei datasets from 45 healthy human hearts, 70 hearts with dilated cardiomyopathy (DCM), and 8 hearts with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC). Interactions between B cells and other cell types were investigated using the CellChat Package. Differential gene expression analysis comparing B cells across conditions was performed using DESeq2. Pathway analysis was performed using Ingenuity, KEGG, and GO pathways analysis.

Results

We identified 1,100 B cells, including naive B cells and plasma cells. B cells showed an extensive network of interactions within the healthy myocardium that included outgoing signaling to macrophages, T cells, endothelial cells, and pericytes, and incoming signaling from endothelial cells, pericytes, and fibroblasts. This niche relied on ECM-receptor, contact, and paracrine interaction; and changed significantly in the context of cardiomyopathy, displaying disease-specific features. Differential gene expression analysis showed that in the context of DCM both naive and plasma B cells upregulated several pathways related to immune activation, including upregulation of oxidative phosphorylation, upregulation of leukocyte extravasation, and, in naive B cells, antigen presentation.

Discussion

The human myocardium contains naive B cells and plasma cells, integrated into a diverse and dynamic niche that has distinctive features in healthy myocardium, DCM, and ARVC. Naive myocardial-associated B cells likely contribute to the pathogenesis of human DCM.

β-Caryophyllene Inhibits Endothelial Tube Formation by Modulating the Secretome of Hypoxic Lung Cancer Cells-Possible Role of VEGF Downregulation

β-Caryophyllene (BCP), a bicyclic sesquiterpene that is a component of the essential oils of various spice and food plants, has been described as a selective CB2 cannabinoid receptor agonist. In the present study, the effect of BCP on angiogenesis was investigated. It was found that conditioned media (CM) from BCP-treated hypoxic A549 lung cancer cells exhibited a concentration-dependent inhibitory effect on human umbilical vein endothelial cell (HUVEC) tube formation induced by CM from vehicle-treated hypoxic A549 cells. There was an associated concentration-dependent decrease in the proangiogenic factor vascular endothelial growth factor (VEGF) in the CM, with both BCP inhibitory effects (tube formation, VEGF secretion) being CB2 receptor-dependent. A reduction of the transcription factor hypoxia-inducible factor 1α (HIF-1α) was furthermore detected. The antiangiogenic and VEGF-lowering properties of BCP were confirmed when CM from another lung cancer cell line, H358, were tested. When directly exposed to HUVECs, BCP showed no significant effect on tube formation, but at 10 µM, impaired VEGF receptor 2 (VEGFR2) phosphorylation triggered by recombinant VEGF in a CB2 receptor-independent manner. In summary, BCP has a dual antiangiogenic effect on HUVECs, manifested in the inhibition of tube formation through modulation of the tumor cell secretome and additionally in the inhibition of VEGF-induced VEGFR2 activation. Because the CB2 agonist has no psychoactive properties, BCP should continue to be evaluated preclinically for further antitumor effects.

Chronic Thromboembolic Pulmonary Hypertension: A Review of the Multifaceted Pathobiology

Chronic thromboembolic pulmonary disease results from the incomplete resolution of thrombi, leading to fibrotic obstructions. These vascular obstructions and additional microvasculopathy may lead to chronic thromboembolic pulmonary hypertension (CTEPH) with increased pulmonary arterial pressure and pulmonary vascular resistance, which, if left untreated, can lead to right heart failure and death. The pathobiology of CTEPH has been challenging to unravel due to its rarity, possible interference of results with anticoagulation, difficulty in selecting the most relevant study time point in relation to presentation with acute pulmonary embolism (PE), and lack of animal models. In this article, we review the most relevant multifaceted cross-talking pathogenic mechanisms and advances in understanding the pathobiology in CTEPH, as well as its challenges and future direction. There appears to be a genetic background affecting the relevant pathological pathways. This includes genetic associations with dysfibrinogenemia resulting in fibrinolysis resistance, defective angiogenesis affecting thrombus resolution, and inflammatory mediators driving chronic inflammation in CTEPH. However, these are not necessarily specific to CTEPH and some of the pathways are also described in acute PE or deep vein thrombosis. In addition, there is a complex interplay between angiogenic and inflammatory mediators driving thrombus non-resolution, endothelial dysfunction, and vascular remodeling. Furthermore, there are data to suggest that infection, the microbiome, circulating microparticles, and the plasma metabolome are contributing to the pathobiology of CTEPH.