Comparative analysis of peripheral blood immunoinflammatory landscapes in patients with acute cholangitis and its secondary septic shock using single-cell RNA sequencing

BACKGROUND

Acute cholangitis (AC) is a key pathogeny of septic shock, which has a high mortality rate. AC has significant clinical heterogeneity, but no study has analyzed the discrepancies in immunoresponsiveness between AC and its secondary septic shock. The immune inflammatory responses play a critical role in the development of septic shock.

METHODS

We performed single-cell RNA sequencing (scRNA-seq) to analyze the differences of immunocytes in immunoresponse and inflammation between the early stages of AC (A1, A2, and A3) and its secondary septic shock (B1, B2, and B3).

RESULTS

This study has identified seven cell types, including T cells, B cells, plasma cells, neutrophils, monocytes, platelets and erythrocytes. We mainly focused on neutrophils, monocytes, and T cells. Neutrophil subpopulation analysis indicated that neutrophil progenitors (proNeus) were identified in neutrophil subsets. Compared with patients suffering from AC, the gene phenotypes of proNeus (ELANE, AZU1, MPO, and PRTN3) were significantly upregulated in septic shock. The differentiation direction of neutrophil subsets in peripheral blood mononuclear cells (PBMCs) was determined; Moreover, the proNeus in septic shock presented a state of "expansion", with upregulation of neutrophil degranulation and downregulation of monocyte and T cell proliferation. Neutrophils-7 (CCL5, RPL23A, RPL13, RPS19 and RPS18) were mainly involved in the regulation of cellular functions. The neutrophils-7 subpopulation in septic shock were in a state of "exhaustion", and its biological functions showed the characteristics of weakening neutrophil migration and phagocytosis, etc., which maked infection difficult to control and aggravated the development of septic shock. Analysis of monocyte and T cell subpopulations showed that the expression genes and biological functions of subpopulations were closely related to immunoinflammatory regulation. In addition, CCL3 - CCR1, CXCL1 - CXCR2 and other ligand-receptors were highly expressed in neutrophils and monocytes, enhancing interactions between immune cells.

CONCLUSION

ScRNA-seq revealed significant differences in immune cells between AC and its secondary septic shock, which were primarily manifested in the cellular numbers, differentially expressed genes, functions of cellular subsets, differentiation trajectories, cell-cell interactions and so on. We identified many subsets of neutrophil, T cell and monocyte were associated with inflammation and immunosuppression induced by septic shock. These provided a reference for accurately evaluating the pathological severity of patients with AC and discovering the targets for therapy.

[Relationship between Wound Age and the Expression of Fzd2 in Rats Skeletal Muscle after Contusion]

OBJECTIVES

To investigate the relationship between wound age and the expressions of frizzled-2 （Fzd2） mRNA and its protein in rats skeletal muscle after contusion, and to explore its possibility of being an index for wound age estimation.

METHODS

The mRNA and protein expressions of Fzd2 in rats skeletal muscle of the control group and the experimental group within 4-48 h after contusion were detected per 4 h by RT-qPCR and Western blotting.

RESULTS

AThe relative expression of Fzd2 mRNA increased at 24 h, 36 h and 40 h after contusion, and the expression at 24 h was twice as the control group （ P<0.05）. The relative expression of Fzd2 protein changed inconspicuously after contusion （P>0.05）.

CONCLUSIONS

The changes of Fzd2 mRNA expression after contusion in a certain time can be a basis to estimate wound age by combined multi-indicators.

Melatonin at pharmacological concentrations suppresses osteoclastogenesis via the attenuation of intracellular ROS

Osteoporosis is linked to age-related decline of melatonin production; however, the direct effects of melatonin on osteoclastogenesis remain unknown. Our study demonstrates that melatonin at pharmacological concentrations, rather than at physiological concentrations, significantly inhibits osteoclastogenesis. Melatonin-mediated anti-osteoclastogenesis involves a reactive oxygen species (ROS)-mediated but not a silent information regulator type 1 (SIRT1)-independent pathway.

INTRODUCTION

Osteoporosis is a bone disorder linked to impaired bone formation and excessive bone resorption. Melatonin has been suggested to treat osteoporosis due to its beneficial actions on osteoblast differentiation. However, the direct effects of melatonin on osteoclastogenesis in bone marrow monocytes (BMMs) remain unknown. This study was to investigate whether melatonin at either physiological or pharmacological concentrations could affect osteoclast differentiation.

METHODS

Primary BMMs were isolated from the femurs and tibias of C57BL/6 mice and were induced toward multinucleated osteoclasts, in the presence of melatonin at either physiological (0.01 to 10 nM) or pharmacological (1 to 100 μM) concentrations. Tartrate-resistant acid phosphatase (TRAP) staining was used to label multinucleated osteoclasts and the levels of osteoclast-specific genes were evaluated. To further explore the underlying mechanisms, the roles of silent information regulator type 1 (SIRT1) and reactive oxygen species (ROS) were evaluated.

RESULTS

We found that melatonin at pharmacological concentrations, rather than at physiological concentrations, significantly inhibited osteoclast formation in a dose-dependent manner. The number of TRAP-positive cells and the gene expression of osteoclast-specific markers were significantly downregulated in melatonin-treated BMMs. The melatonin-mediated repression of osteoclast differentiation involved the inhibition of the nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) signaling pathway. The treatment with SIRT1 inhibitors did not affect osteoclast differentiation but, when supplemented with exogenous hydrogen peroxide, a partial rescue of melatonin-suppressed osteoclastogenesis was observed.

CONCLUSION

Melatonin at pharmacological doses directly inhibited osteoclastogenesis of BMMs by a ROS-mediated but not a SIRT1-independent pathway.

The role of laminins in cartilaginous tissues: from development to regeneration

As a key molecule of the extracellular matrix, laminin provides a delicate microenvironment for cell functions. Recent findings suggest that laminins expressed by cartilage-forming cells (chondrocytes, progenitor cells and stem cells) could promote chondrogenesis. However, few papers outline the effect of laminins on providing a favorable matrix microenvironment for cartilage regeneration. In this review, we delineated the expression of laminins in hyaline cartilage, fibrocartilage and cartilage-like tissue (nucleus pulposus) throughout several developmental stages. We also examined the effect of laminins on the biological activities of chondrocytes, including adhesion, migration and survival. Furthermore, we scrutinized the potential influence of various laminin isoforms on cartilage-forming cells' proliferation and chondrogenic differentiation. With this information, we hope to facilitate the understanding of the spatial and temporal interactions between cartilage-forming cells and laminin microenvironment to eventually advance cell-based cartilage engineering and regeneration.

Biomechanical signals guiding stem cell cartilage engineering: from molecular adaption to tissue functionality

In vivo cartilage is in a state of constant mechanical stimulation. It is therefore reasonable to deduce that mechanical forces play an important role in cartilage formation. Mechanical forces, such as compression, tension, and shear force, have been widely applied for cartilage engineering; however, relatively few review papers have summarized the influence of biomechanical signals on stem cell-based neo-cartilage formation and cartilage engineering in both molecular adaption and tissue functionality. In this review, we will discuss recent progress related to the influences of substrate elasticity on stem cell chondrogenic differentiation and elucidate the potential underlying mechanisms. Aside from active sensing and responding to the extracellular environment, stem cells also could respond to various external mechanical forces, which also influence their chondrogenic capacity; this topic will be updated along with associated signaling pathways. We expect that these different regimens of biomechanical signals can be utilized to boost stem cell-based cartilage engineering and regeneration.

Evolving concepts of chondrogenic differentiation: history, state-of-the-art and future perspectives

As a cell source, multipotent mesenchymal stromal cells or mesenchymal stem cells (MSCs) are promising candidates for chondrogenic differentiation and subsequent cartilage regeneration. From previous literature, it is known that chondrogenic differentiation of MSCs inevitably leads to hypertrophy and subsequent endochondral ossification. In this review, we examine the history of currently established protocols of chondrogenic differentiation and elaborate on the roles of individual components of chondrogenic differentiation medium. We also summarise the effects of physical, chemical and biological factors involved, and propose potential strategies to differentiate MSCs into articular chondrocytes with homogenous mature phenotypes through spatial-temporal incorporation of cell differentiation and chondrogenesis.

Common variant in VEGFA and response to anti-VEGF therapy for neovascular age-related macular degeneration

Age-related macular degeneration (AMD) is a leading cause of visual impairment in aging populations in industrialized countries. Here we investigated whether the genotype of vascular endothelial growth factor A (VEGFA) gene is associated with response to anti-VEGF therapy. 223 eyes with neovascular AMD were treated with intravitreal anti-VEGF therapy. Responders were defined as patients who had an improvement in best corrected visual acuity (BCVA) of at least 5 letters or one line on the EDTRS visual acuity chart along with resolution of intraretinal or subretinal fluid over 12 months. Patients who did not meet the definition of responders were classified as poor-responders. The vision of responders (n = 148) improved while the vision of poor-responders (n = 75) worsened (P<0.001). Responders on average had a decrease in central foveal thickness (CFT), while poor-responders had an increase in CFT (P <0.001). Compared with the responder group, the poor-responder group had a higher frequency of the risk (T) allele (Allelic P = 0.019) and TT genotype (P = 0.002 under a recessive model) for the VEGFA-rs943080 polymorphism. VEGFA expression was 1.8-fold higher in cells with the VEGFA rs943080 TT genotype than in cells with the VEGFA rs943080 CC genotype (P = 0.012). Age, gender, smoking, diabetes mellitus, and hypertension did not play a significant role in treatment response, but BMI was found to be significantly different between responders and poorresponders (P = 0.033). In conclusion, we demonstrated a potential pharmacogenetic relationship between the VEGFA gene and treatment response to anti-VEGF therapy.The studies are registered at ClinicalTrials.gov under the identifiers NCT00474695 (http://clinicaltrials. gov/ct2/show/NCT00474695) and NCT01464723 (http://clinicaltrials.gov/ct2/show/NCT01464723).

A review of decellularized stem cell matrix: a novel cell expansion system for cartilage tissue engineering

Cell-based therapy is a promising biological approach for the treatment of cartilage defects. Due to the small size of autologous cartilage samples available for cell transplantation in patients, cells need to be expanded to yield a sufficient cell number for cartilage repair. However, chondrocytes and adult stem cells tend to become replicatively senescent once they are expanded on conventional plastic flasks. Many studies demonstrate that the loss of cell properties is concomitant with the decreased cell proliferation capacity. This is a significant challenge for cartilage tissue engineering and regeneration. Despite much progress having been made in cell expansion, there are still concerns over expanded cell size and quality for cell transplantation applications. Recently, in vivo investigations in stem cell niches have suggested the importance of developing an in vitro stem cell microenvironment for cell expansion and tissue-specific differentiation. Our and other investigators' work indicates that a decellularized stem cell matrix (DSCM) may provide such an expansion system to yield large-quantity and high-quality cells for cartilage tissue engineering and regeneration. This review briefly introduces key parameters in an in vivo stem cell niche and focuses on our recent work on DSCM for its rejuvenating or reprograming effect on various adult stem cells and chondrocytes. Since research in DSCM is still in its infancy, we are only able to discuss some potential mechanisms of DSCM on cell proliferation and chondrogenic potential. Further investigations of the underlying mechanism and in vivo regeneration capacity will allow this approach to be used in clinics.

Repair of full-thickness femoral condyle cartilage defects using allogeneic synovial cell-engineered tissue constructs

OBJECTIVE

Synovium-derived stem cells (SDSCs) have proven to be superior in cartilage regeneration compared with other sources of mesenchymal stem cells. We hypothesized that conventionally passaged SDSCs can be engineered in vitro into cartilage tissue constructs and the engineered premature tissue can be implanted to repair allogeneic full-thickness femoral condyle cartilage defects without immune rejection.

METHODS

Synovial tissue was harvested from rabbit knee joints. Passage 3 SDSCs were mixed with fibrin glue and seeded into non-woven polyglycolic acid (PGA) mesh. After 1-month incubation with growth factor cocktails, the premature tissue was implanted into rabbit knees to repair osteochondral defects with Collagraft as a bone substitute in the Construct group. Fibrin glue-saturated PGA/Collagraft composites were used as a Scaffold group. The defect was left untreated as an Empty group.

RESULTS

SDSCs were engineered in rotating bioreactor systems into premature cartilage, which displayed the expression of sulfated glycosaminoglycan (GAG), collagen II, collagen I, and macrophages. Six months after implantation with premature tissue, cartilage defects were full of smooth hyaline-like cartilage with no detectable collagen I and macrophages but a high expression of collagen II and GAG, which were also integrated with the surrounding native cartilage. The Scaffold and Empty groups were resurfaced with fibrous-like and fibrocartilage tissue, respectively.

CONCLUSION

Allogeneic SDSC-based premature tissue constructs are a promising stem cell-based approach for cartilage defects. Although in vitro data suggest that contaminated macrophages affected the quality of SDSC-based premature cartilage, effects of macrophages on in vivo tissue regeneration and integration necessitate further investigation.

Over-expression of a flower-specific transcription factor gene AtMYB24 causes aberrant anther development

In plants, MYB transcription factors play important roles in many developmental processes and various defense responses. AtMYB24, as a member of R2R3-MYB gene family in Arabidopsis, was found mainly expressed in flowers, especially in microspores and ovules using Northern blots and in situ hybridization. It was further found that the expression of AtMYB24 was tightly regulated during anther development. Over-expression of AtMYB24 in transgenic plants resulted in pleiotropic phenotypes, including dwarfism and flower development defects, in particular, producing abnormal pollen grains and non-dehiscence anthers. Further analysis showed that the anther development of the AtMYB24-ox lines was retarded starting from the anther developmental stages 10-11. At stages 12 and 13, the septum and stomium cells of anthers would not break, and fewer or no fibrous bands were found in the endothecium and connective cells in the AtMYB24-ox plants. Similar aberrant anther phenotype was also observed in the AtMYB24-GR-ox lines treated with dexamethasone (DEX). Quantitative real-time PCR showed expression of genes involved in phenylpropanoid biosynthetic pathway, such as CHS and DFR, and AtGTP2 were altered in AtMYB24-ox lines. These results suggest an important role of AtMYB24 in the normal development of anthers in Arabidopsis.

Long-term culture of tissue engineered cartilage in a perfused chamber with mechanical stimulation

One approach to functional tissue engineering of cartilage is to utilize bioreactors to provide environmental conditions that stimulate chondrogenesis in cells cultured on biomaterial scaffolds. We report the combined use of a three-dimensional in vitro model and a novel bioreactor with perfusion of culture medium and mechanical stimulation in long-term studies of cartilage development and function. To engineer cartilage, scaffolds made of a non-woven mesh of polyglycolic acid (PGA) were seeded with bovine calf articular chondrocytes, cultured for an initial 30-day period under free swelling conditions, and cultured for an additional 37 day period in one of the three groups: (1) free-swelling, (2) static compression (on 24 h/day, strain control, static offset 10%), and (3) dynamic compression (on 1 h/day; off 23 h/day; strain control, static offset 2%, dynamic strain amplitude 5%; frequency 0.3 Hz). Constructs were sampled at timed intervals and assessed with respect to structure, biochemical composition, and mechanical function. Mechanical simulation had little effect on the compositions, morphologies and on mechanical properties of construct interiors discs, but it resulted in distincly different properties of the peripheral rings and face sides. Contructs cultured with mechanical loading maintained their cylindrical shape with flat and parallel top and bottom surfaces, and retained larger amounts of GAG. The modular bioreactor system with medium perfusion and mechanical loading can be utilized to define the conditions of cultivation for functional tissue engineering of cartilage.

[Fatal side-effects of all-trans retinoic acid in the treatment of acute promyelocytic leukemia]

Of 82 patients with acute promyelocytic leukemia (APL) who were treated with all-trans retinoic acid (ATRA), 35 developed leukocytosis and 22 fatal side-effects(15 with retinoic acid syndrome and 7 intracranial bleeding). There was a high mortality in the patient with fatal side-effects. The relationship between leukocytosis and fatal side-effects was analyzed and the effect of therapeutic interventions on the development and prognosis of the fatal side-effects was investigated. The results showed that leukocytosis was a risk factor of the development of fatal side-effects in APL treated with ATRA. ATRA combined with small dose of harringtonin in treating APL can reduce the incidence of intracranial bleeding resulted from leukocytosis and corticosteroid can decrease the mortality of retinoic acid syndrome.

Growth factors for sequential cellular de- and re-differentiation in tissue engineering

A model system for the in vitro generation of cartilaginous constructs was used to study a tissue engineering paradigm whereby sequentially applied growth factors promoted chondrocytes to first de-differentiate into a proliferative state and then re-differentiate and undergo chondrogenesis. Early cultivation in medium with supplemental TGF-beta1/FGF-2 doubled cell fractions in 2-week constructs compared to unsupplemented controls. Subsequent culture with supplemental IGF-I yielded large 4-week constructs with high fractions of cartilaginous extracellular matrix (ECM) and high compressive moduli, whereas prolonged culture with supplemental FGF-2 yielded small 4-week constructs with low ECM fractions and moduli. Sequential supplementation with TGF-beta1/FGF-2 and then IGF-I yielded 4-week constructs with type-specific mRNA expression and protein levels that were high for type II and negligible for type I collagen, in contrast to other growth factor regimens studied. The data demonstrate that structural, functional, and molecular properties of engineered cartilage can be modulated by sequential application of growth factors.

Expression of collagen type I, II and III in loose body of osteoarthritis

The expression of collagen type I, II, and III was investigated to evaluate phenotypic change in chondrocytes in loose bodies related to osteoarthritis. We assessed collagen type I, II, and III production in loose bodies from knee joints of ten osteoarthritic patients, using an immunohistochemical method with monoclonal antibodies. Collagen type III expression was identified in all ten loose bodies and was mainly located in cartilage, including chondrocytes and matrices, as well as in a layer of fibroid tissue on the surface. No positive signal for collagen type III was observed in necrotic osteocytes. There was weakly positive staining for collagen type I in chondrocytes. No positive staining for collagen type II could be seen in the cartilage of loose bodies. Cartilage from the non-osteoarthritic knee joints of four people was negative for the expression of collagen type I and III, and positive for the expression of collagen type II. Collagen type I and III expression suggested the dedifferentiation status of chondrocytes in loose bodies.

[Correlativity analysis of detoxicating effect of radix Glycyrrhizae on radix Aconiti preparata in sini decoction]

Based on fixed dosages of Radix Aconiti Preparata and Rhizoma Zingiberis and six different dosages of Radix Glycyrrhizae, six different Sini Decoctions were prepared. The aconitine in these decoctions was determined by TLC-scanning. Statistical analysis was used in the experiment. It has been confirmed that the quantity of aconitine reduces with the increase of the quantity of Radix Glycyrrhizae, assuming a significant negative correlativity, r = -0.9945.