Cyclic GMP-AMP Synthase (cGAS) Deletion Reduces Severity in Bilateral Nephrectomy Mice through Changes in Neutrophil Extracellular Traps and Mitochondrial Respiration

A self-gelling hemostatic powder boosting radiotherapy-elicited NK cell immunity to combat postoperative hepatocellular carcinoma relapse

Liver resection represents a main curative treatment for patients with early-stage hepatocellular carcinoma (HCC), but there is a rather high incidence of postoperative HCC relapse, which severely shortens long-term survival time. Currently, no standard adjuvant strategies are available for preventing HCC relapse in clinical practice. Impaired natural killer (NK) cell anti-tumor immunity has been disclosed as a crucial root of HCC relapse, indicating that reinstating NK cell anti-tumor immunity may show promise to curb HCC relapse. Coincidently, mounting evidence shows that radiotherapy (RT) can trigger NK cell anti-tumor immunity, though its mechanisms have never been completely elucidated. Herein, we uncover that RT can induce immunogenic cell death and activate cGAS-STING pathway in HCC cells to elicit NK cell anti-tumor immunity. However, RT is also revealed to enhance autophagy and CD73 expression in HCC cells, as well as neutrophil extracellular traps (NETs) formation, which largely limits RT-induced activation of NK cell anti-tumor immunity. Therefore, a cocktail of autophagy inhibitor 3-methyladenine, CD73 inhibitor ARL 67156 trisodium and NETs lyase DNase I may sensitize RT to reinvigorate NK cell anti-tumor immunity and thus prevent HCC relapse postresection. To minimize therapy-related side effects, a nanocomposite powder encapsulating such a triple-drug cocktail is developed. This powder can rapidly form adhesive hydrogel in situ after applied to surgical margin, consequently fulfilling liver-localized sustained drug delivery. Importantly, it can sensitize RT to reinstate NK cell anti-tumor immunity to combat postoperative HCC relapse in Heap1-6-HCC murine model. Besides, this powder can also generate rapid hemostasis in rat and porcine models. Altogether, this work provides an innovative strategy to thwart postoperative HCC relapse and bleeding.

Accelerating and protective effects toward cancer growth in cGAS and FcgRIIb deficient mice, respectively, an impact of macrophage polarization

BACKGROUND

Due to the possible influence of inflammation and gut microbiota in cancers.

METHODS

Fc gamma receptor IIb deficient (FcGRIIb-/-) and cyclic GMP-AMP synthase deficient (cGAS-/-) mice, the model with hyperinflammation and hypo-inflammation, respectively, were subcutaneously injected with MC38 cells (a murine colon cancer cell line).

RESULTS

As such, the tumor burdens were most prominent in cGAS-/- mice, while FcGRIIb-/- mice demonstrated the least tumor sizes compared with wild-type (WT). Intra-tumoral mononuclear cells of FcGRIIb-/- (hematoxylin and eosin staining) were more prominent than other groups with the most dominant CD86-positive cells (mostly M1 proinflammatory macrophages) and the least CD206-positive cells (mostly M2 anti-inflammatory macrophages). While fecal microbiome analysis demonstrated a subtle difference among mouse strains with tumors at 24 days post-cancer injection, serum cytokines (TNF-α, IL-6, IL-1α, IFN-β, IFN-γ, IL-23, IL-12p70, GM-CSF, IL-27, and IL-17A) (fluorescence-encoded bead multiplex assay) and the expansion of immune cells in the spleens of FcGRIIb-/- mice (flow cytometry) were more prominent than others. With bone marrow-derived macrophages, prominent M1 (LPS) and M2 polarization (IL4 and cancer supernatant) in FcGRIIb-/- and cGAS-/- macrophages, respectively, were demonstrated using polymerase chain reaction and flow cytometry. The most prominent tumoricidal activity (percentage of F4/80-negative flexible780 viable dye-positive cells using flow cytometry) of LPS-stimulated FcGRIIb-/- macrophages compared with other groups supported dominant pro-inflammatory characteristics of FcGRIIb-/- macrophages.

CONCLUSIONS

In conclusion, the protective and promoting effects of FcGRIIb-/- and cGAS-/- mice, respectively, against cancers are partly related to macrophage functions with a subtle correlation to fecal microbiota, and FcGRIIb inhibitors and cGAS enhancers might be helpful for cancer adjuvant treatment.

Intratracheal Candida administration induced lung dysbiosis, activated neutrophils, and worsened lung hemorrhage in pristane-induced lupus mice

Because the innate immunity might and fungi in the lungs might enhance the severity of lupus-induced diffuse alveolar hemorrhage (DAH), intraperitoneal pristane injection was performed in C57BL6 mice with intratracheal administration by Candida albicans or phosphate buffer solution (PBS). Despite the similar pristane-induced lupus (proteinuria, serum creatinine, and serum anti-dsDNA) at 5 weeks of the model, Candida administration worsened several characteristics, including mortality, body weight, serum cytokines (TNF-α and IL-6), and lung hemorrhage score, and cytokines in the lung tissue (TNF-α, IL-6, and IL-10), but not gut permeability (FITC-dextran assay), serum IL-10, immune cells in the spleens (flow cytometry analysis), and activities of peritoneal macrophages (polymerase-chain reaction). Although Candida administration reduced proteobacterial abundance and altered alpha and beta diversity compared with PBS control, lung microbiota was not different between Candida administration in pristane- and non-pristane-administered mice. Because of the prominent Gram-negative bacteria in lung microbiota and the role of neutrophils in DAH, lipopolysaccharide (LPS) with and without heat-killed Candida preparation was tested. Indeed, Candida preparation with LPS induced more severe pro-inflammatory neutrophils than LPS stimulation alone as indicated by the expression of several genes (TNF-α, IL-6, IL-1β, IL-10, Dectin-1, and NF-κB). In conclusion, the intratracheal Candida worsened pristane-induced lung hemorrhage partly through the enhanced neutrophil responses against bacteria and fungi. More studies on Candida colonization in sputum from patients with lupus-induced DAH are interesting.

Discovery of a Novel CRBN-Recruiting cGAS PROTAC Degrader for the Treatment of Ulcerative Colitis

Cyclic GMP-AMP synthase (cGAS), a critical cytosolic DNA sensor initiating innate immune responses in the presence of cytosolic DNA, is increasingly recognized as a promising therapeutic target for ulcerative colitis (UC). Here, we reported the design, synthesis, structure-activity relationship exploration and biological evaluation of a novel class of CRBN-recruiting cGAS-targeting PROTAC degraders. Among them, TH35 exhibited the most favorable degradation profile, achieving potent and selective degradation of cGAS, and markedly attenuated dsDNA-induced activation of cGAS signaling in both human and murine cells, with minimal cytotoxic effects. In vivo, TH35 demonstrated superior therapeutic efficacy in a dextran sulfate sodium (DSS)-induced mouse model of UC compared to the corresponding cGAS inhibitor, while also displaying acceptable pharmacokinetic properties. Collectively, TH35 as the first CRBN-recruiting cGAS PROTAC holds promise for augmenting anti-inflammatory responses and offers a new avenue for treating cGAS-driven inflammatory diseases.

Extracellular traps in peripheral blood mononuclear cell fraction in childhood-onset systemic lupus erythematosus

Although the role of low-density granulocytes (LDGs), neutrophils in the peripheral blood mononuclear cell (PBMC) fraction, and neutrophil extracellular traps (NETs) in assessing lupus disease severity is acknowledged, data specific to childhood-onset lupus remains scarce. This study analyzed 46 patients with childhood-onset systemic lupus erythematosus (82.6% females, mean age 14.5 ± 0.3 years), including 26 cases with normal complement levels and 20 with low complement levels, along with 20 healthy adult volunteers. Key parameters that distinguished healthy volunteers from lupus patients and differentiated between lupus patients with low and normal complement were serum interferon (IFN)-α, serum citrullinated histone 3 (CitH3), and extracellular traps (ETs) in LDGs. However, NETs (assessed by nuclear staining morphology), LDG abundance, and other parameters (such as endotoxemia, cytokines, and double-stranded (ds) DNA) did not show such differentiation. When lipopolysaccharide (LPS) was administered to LDGs in the PBMC fraction, it induced ETs in both low and normal complement groups, indicating the inducible nature of ETs. In adult healthy volunteers, activation by recombinant IFN-α or dsDNA in isolated neutrophils induced LDGs and NETs (identified using immunofluorescent staining for CitH3, myeloperoxidase, and neutrophil elastase) at 45 min and 3 h post-stimulation, respectively. Additionally, approximately half of the LDGs underwent late apoptosis at 3 h post-stimulation, as determined by flow cytometry analysis. Activation by IFN-α or dsDNA in LDGs also led to a more pronounced expression of CD66b, an adhesion molecule, compared to regular-density neutrophils, suggesting higher activity in LDGs. In conclusion, IFN-α and/or dsDNA in serum may transform regular-density neutrophils into LDGs before progressing to NETosis and apoptosis, potentially exacerbating lupus severity through cell death-induced self-antigens. Therefore, LDGs and ETs in LDGs could provide deeper insights into the pathophysiology of childhood-onset lupus.

Neutrophil Diversity (Immature, Aged, and Low-Density Neutrophils) and Functional Plasticity: Possible Impacts of Iron Overload in β-Thalassemia

Neutrophil dysfunction is a form of immune suppression in patients with β-thalassemia (Beta-thal), although data on this are limited. In this study, blood from patients and healthy volunteers was analyzed. Flow cytometry analysis demonstrated an increase in immature neutrophils (CD16- CD62L+) and aged (senescent) neutrophils (CD16+ CD62L-) in Beta-thal patients compared to healthy volunteers. The Beta-thal neutrophils demonstrated less prominent chemotaxis and phagocytosis than healthy neutrophils at the baseline. With phorbol myristate acetate (PMA) or lipopolysaccharide (LPS) stimulations, some of the indicators, including the flow cytometry markers (CD11b, CD62L, CD66b, CD63, apoptosis, and reactive oxygen species) and neutrophil extracellular traps (NETs; detected by anti-citrullinated histone 3 immunofluorescence), were lower than the control. Additionally, low-density neutrophils (LDNs), which are found in the peripheral blood mononuclear cell (PBMC) fraction, were observed in Beta-thal patients but not in the control group. The expression of CD11b, CD66b, CD63, arginase I, and ROS in LDNs was higher than the regular normal-density neutrophils (NDNs). The proliferation rate of CD3+ T cells isolated from the PBMC fraction of healthy volunteers was higher than that of the cells from patients with Beta-thal. The incubation of red blood cell (RBC) lysate plus ferric ions with healthy NDNs transformed the NDNs into the aged neutrophils (decreased CD62L) and LDNs. In conclusion, iron overload induces neutrophil diversity along with some dysfunctions.

Mitochondrial UCP1: Potential thermogenic mechanistic switch for the treatment of obesity and neurodegenerative diseases using natural and epigenetic drug candidates

BACKGROUND

Brown fat is known to provide non-shivering thermogenesis through mitochondrial uncoupling mediated by uncoupling protein 1 (UCP1). Non-shivering is not dependent on UCP2, UCP4, and BMCP1/UCP5 genes, which are distinct from UCP1 in a way that they are not constitutive uncouplers. Although they are susceptible to free fatty acid and free radical activation, their functioning has a significant impact on the performance of neurons.

METHODOLOGY

Using subject-specific keywords (Adipose tissue; Adipocytes; Mitochondria; Obesity; Thermogenesis; UCP's in Neurodegeneration; Alzheimer's disease; Parkinson's disease), research articles and reviews were retrieved from Web of Science, ScienceDirect, Google Scholar, and PubMed. This article includespublications published between 2018 and 2023. The drugs that upregulate UCP1 are included in the study while the drugs that do not impact UCP1 are were not included.

RESULTS

Neuronal UCPs have a direct impact on synaptic plasticity, neurodegenerative processes, and neurotransmission, by modulating calcium flux, mitochondrial biogenesis, local temperature, and free radical generation. Numerous significant advances in the study of neuronal UCPs and neuroprotection are still to be made. Identification of the tissue-dependent effects of UCPs is essential first. Pharmacologically targeting neuronal UCPs is a key strategy for preventing both neurodegenerative diseases and physiological aging. Given that UCP2 has activities that are tissue-specific, it will be essential to develop treatments without harmful side effects. The triggering of UCPs by CoQ, an essential cofactor, produces nigral mitochondrial uncoupling, reduces MPTP-induced toxicity, and may even decrease the course of Parkinson's disease, according to early indications.

CONCLUSION

Herein, we explore the potential of UCP1 as a therapeutic target for treating obesity, neurodegenerative diseases as well as a potential activator of both synthetic and natural drugs. A deeper knowledge of synaptic signaling and neurodegeneration may pave the way to new discoveries regarding the functioning and controlling of these genes.

Bacteriophages isolated from mouse feces attenuates pneumonia mice caused by Pseudomonas aeruginosa

BACKGROUND

Most of the current bacteriophages (phages) are mostly isolated from environments. However, phages isolated from feces might be more specific to the bacteria that are harmful to the host. Meanwhile, some phages from the environment might affect non-pathogenic bacteria for the host.

METHODS

Here, bacteriophages isolated from mouse feces were intratracheally (IT) or intravenously (IV) administered in pneumonia mice caused by Pseudomonas aeruginosa at 2 hours post-intratracheal bacterial administration. As such, the mice with phage treatment, using either IT or IV administration, demonstrated less severe pneumonia as indicated by mortality, serum cytokines, bacteremia, bacterial abundance in bronchoalveolar lavage fluid (BALF), and neutrophil extracellular traps (NETs) in lung tissue (immunofluorescence of neutrophil elastase and myeloperoxidase).

RESULTS

Interestingly, the abundance of phages in BALF from the IT and IV injections was similar, supporting a flexible route of phage administration. With the incubation of bacteria with neutrophils, the presence of bacteriophages significantly improved bactericidal activity, but not NETs formation, with the elevated supernatant IL-6 and TNF-α, but not IL-1β. In conclusion, our findings suggest that bacteriophages against Pseudomonas aeruginosa can be discovered from feces of the host.

CONCLUSIONS

The phages attenuate pneumonia partly through an enhanced neutrophil bactericidal activity, but not via inducing NETs formation. The isolation of phages from the infected hosts themselves might be practically useful for future treatment. More studies are warranted.

Crosstalk between neutrophil extracellular traps and immune regulation: insights into pathobiology and therapeutic implications of transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-associated death, occurring during or within 6 hours after transfusion. Reports indicate that TRALI can be categorized as having or lacking acute respiratory distress syndrome (ARDS) risk factors. There are two types of TRALI in terms of its pathogenesis: antibody-mediated and non-antibody-mediated. The key initiation steps involve the priming and activation of neutrophils, with neutrophil extracellular traps (NETs) being established as effector molecules formed by activated neutrophils in response to various stimuli. These NETs contribute to the production and release of reactive oxygen species (ROS) and participate in the destruction of pulmonary vascular endothelial cells. The significant role of NETs in TRALI is well recognized, offering a potential pathway for TRALI treatment. Moreover, platelets, macrophages, endothelial cells, and complements have been identified as promoters of NET formation. Concurrently, studies have demonstrated that the storage of platelets and concentrated red blood cells (RBC) can induce TRALI through bioactive lipids. In this article, recent clinical and pre-clinical studies on the pathophysiology and pathogenesis of TRALI are reviewed to further illuminate the mechanism through which NETs induce TRALI. This review aims to propose new therapeutic strategies for TRALI, with the hope of effectively improving its poor prognosis.