Activation of platelet-activating factor receptor exacerbates renal inflammation and promotes fibrosis

Role of Platelet Activating Factor as a Mediator of Inflammatory Diseases and Preterm Delivery

Nearly 70% of preterm deliveries occur spontaneously, and the clinical pathways involved include preterm labor and preterm premature rupture of membranes. Prediction of preterm delivery is considered crucial due to the significant effects of preterm birth on health and the economy at both the personal and community levels. Although similar inflammatory processes occur in both term and preterm delivery, the premature activation of these processes or exaggerated inflammatory response triggered by infection or sterile factors leads to preterm delivery. Platelet activating factor (PAF) is a phosphoglycerylether lipid mediator of inflammation that is implicated in infections, cancers, and various chronic diseases and disorders including cardiovascular, renal, cerebrovascular, and central nervous system diseases. In gestational tissues, PAF mediates the inflammatory pathways that stimulate the effector mechanisms of labor, including myometrial contraction, cervical dilation, and fetal membrane rupture. Women with preterm labor and preterm premature rupture of membranes have increased levels of PAF in their amniotic fluid. In mice, the intrauterine or intraperitoneal administration of carbamyl PAF activates inflammation in gestational tissues, thereby eliciting preterm delivery. This review summarizes recent research on PAF as an important inflammatory mediator in preterm delivery and in other inflammatory disorders, highlighting its potential value for prediction, intervention, and prevention of these diseases.

Generation of 3D melanoma models using an assembloid-based approach

While 3D tumor models have greatly evolved over the past years, there is still a strong requirement for more biosimilar models which are capable of recapitulating cellular crosstalk within the tumor microenvironment while equally displaying representative levels of tumor aggressiveness and invasion. Herein, we disclose an assembloid melanoma model based on the fusion of individual stromal multicellular spheroids (MCSs). In contrast to more traditional tumor models, we show that it is possible to develop self-organizing, heterotypic melanoma models where tumor cells present stem-cell like features like up-regulated pluripotency master regulators SOX2, POU5F1 and NANOG. Additionally, these assembloids display high levels of invasiveness while embedded in 3D matrices as evidenced by stromal cell promotion of melanoma cell invasion via metalloproteinase production. Furthermore, sensitivity to anticancer drug doxorubicin was demonstrated for the melanoma assembloid model. These findings suggest that melanoma assembloids may play a significant role in the field of 3D cancer models as they more closely mimic the tumor microenvironment when compared to more traditional MCSs, opening the doors to a better understanding of the role of tumor microenvironment in supporting tumor progression. STATEMENT OF SIGNIFICANCE: The development of complex 3D tumor models that better recapitulate the tumor microenvironment is crucial for both an improved comprehension of intercellular crosstalk and for more efficient drug screening. We have herein developed a self-organizing heterotypic assembloid-based melanoma model capable of closely mimicking the tumor microenvironment. Key features recapitulated were the preservation of cancer cell stemness, sensitivity to anti-cancer agents and tumor cell invasion promoted by stromal cells. The approach of pre-establishing distinct stromal domains for subsequent combination into more complex tumor constructs provides a route for developing superior tumor models with a higher degree of similarity to native cancer tissues.

Differential expression of serum TM, PAF, and CD62P in patients with autologous arteriovenous fistula and the correlation with vascular access function

BACKGROUND

End-stage renal disease (ESRD) is the final stage of chronic kidney disease (CKD).

AIMS

We aimed to analyze the expression differences of serum thrombomodulin (TM), platelet-activating factor (PAF), and P-selectin (CD62P) in patients with autologous arteriovenous fistula (AVF) and the correlation with vascular access function.

METHODS

The case data were retrospectively analyzed. Moreover, 160 patients with AVF maintenance hemodialysis were selected as the AVF group, and 150 healthy participants were selected as the healthy control group. According to the function of vascular access, patients in the AVF group were divided into Group A (n = 50, after the first establishment of AVF), Group B (n = 64, normal vascular access function after hemodialysis treatment), and Group C (n = 46, vascular access failure). Pearson analysis was conducted to explore the correlation between serum TM, PAF, CD62P content, and vascular pathological examination indicators, to evaluate the value of TM, PAF, and CD62P levels in predicting vascular access failure in patients with AVF.

RESULTS AND DISCUSSION

The serum levels of TM, PAF, and CD62P were positively correlated with the expressions of CD68 and MCP-1, respectively (p < .001). Serum TM was positively correlated with the levels of PAF and CD62P (p < .001), and PAF was positively correlated with the levels of CD62P (p < .001), respectively. Serum levels of TM, PAF and CD62P were risk factors for vascular access failure in AVF patients (p < .05). The area under the curve of serum TM, PAF and CD62P levels in predicting vascular access failure in AVF patients was 0.879.

CONCLUSION

The serum levels of TM, PAF, and CD62P in AVF patients were correlated with the vascular access function of AVF patients, which was very important for maintaining the stability of vascular access function, and had certain value in predicting vascular access failure/disorder in AVF patients, and could be popularized and applied.

Localized cardiac small molecule trajectories and persistent chemical sequelae in experimental Chagas disease

Post-infectious conditions present major health burdens but remain poorly understood. In Chagas disease (CD), caused by Trypanosoma cruzi parasites, antiparasitic agents that successfully clear T. cruzi do not always improve clinical outcomes. In this study, we reveal differential small molecule trajectories between cardiac regions during chronic T. cruzi infection, matching with characteristic CD apical aneurysm sites. Incomplete, region-specific, cardiac small molecule restoration is observed in animals treated with the antiparasitic benznidazole. In contrast, superior restoration of the cardiac small molecule profile is observed for a combination treatment of reduced-dose benznidazole plus an immunotherapy, even with less parasite burden reduction. Overall, these results reveal molecular mechanisms of CD treatment based on simultaneous effects on the pathogen and on host small molecule responses, and expand our understanding of clinical treatment failure in CD. This link between infection and subsequent persistent small molecule perturbation broadens our understanding of infectious disease sequelae.

Platelets in Renal Disease

Kidney disease is a major global health concern, affecting millions of people. Nephrologists have shown interest in platelets because of coagulation disorders caused by renal diseases. With a better understanding of platelets, it has been found that these anucleate and abundant blood cells not only play a role in hemostasis, but also have important functions in inflammation and immunity. Platelets are not only affected by kidney disease, but may also contribute to kidney disease progression by mediating inflammation and immune effects. This review summarizes the current evidence regarding platelet abnormalities in renal disease, and the multiple effects of platelets on kidney disease progression. The relationship between platelets and kidney disease is still being explored, and further research can provide mechanistic insights into the relationship between thrombosis, bleeding, and inflammation related to kidney disease, and elucidate targeted therapies for patients with kidney disease.

The molecular mechanisms and therapeutic strategies of EMT in tumor progression and metastasis

Epithelial–mesenchymal transition (EMT) is an essential process in normal embryonic development and tissue regeneration. However, aberrant reactivation of EMT is associated with malignant properties of tumor cells during cancer progression and metastasis, including promoted migration and invasiveness, increased tumor stemness, and enhanced resistance to chemotherapy and immunotherapy. EMT is tightly regulated by a complex network which is orchestrated with several intrinsic and extrinsic factors, including multiple transcription factors, post-translational control, epigenetic modifications, and noncoding RNA-mediated regulation. In this review, we described the molecular mechanisms, signaling pathways, and the stages of tumorigenesis involved in the EMT process and discussed the dynamic non-binary process of EMT and its role in tumor metastasis. Finally, we summarized the challenges of chemotherapy and immunotherapy in EMT and proposed strategies for tumor therapy targeting EMT.

The Role of Platelets in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is among the most common microvascular complications in patients with diabetes, and it currently accounts for the majority of end-stage kidney disease cases worldwide. The pathogenesis of DKD is complex and multifactorial, including systemic and intra-renal inflammatory and coagulation processes. Activated platelets play a pivotal role in inflammation, coagulation, and fibrosis. Mounting evidence shows that platelets play a role in the pathogenesis and progression of DKD. The potentially beneficial effects of antiplatelet agents in preventing progression of DKD has been studied in animal models and clinical trials. This review summarizes the current knowledge on the role of platelets in DKD, including the potential therapeutic effects of antiplatelet therapies.

Function and regulation of GPX4 in the development and progression of fibrotic disease

Fibrosis is a common feature of fibrotic diseases that poses a serious threat to global health due to high morbidity and mortality in developing countries. There exist some chemical compounds and biomolecules associated with the development of fibrosis, including cytokines, hormones, and enzymes. Among them, glutathione peroxidase 4 (GPX4), as a selenoprotein antioxidant enzyme, is widely found in the embryo, testis, brain, liver, heart, and photoreceptor cells. Moreover, it is shown that GPX4 elicits diverse biological functions by suppressing phospholipid hydroperoxide at the expense of decreased glutathione (GSH), including loss of neurons, autophagy, cell repair, inflammation, ferroptosis, apoptosis, and oxidative stress. Interestingly, these processes are intimately related to the occurrence of fibrotic disease. Recently, GPX4 has been reported to exhibit a decline in fibrotic disease and inhibit fibrosis, suggesting that alterations of GPX4 can change the course or dictate the outcome of fibrotic disease. In this review, we summarize the role and underlying mechanisms of GPX4 in fibrosis diseases such as lung fibrosis, liver fibrosis, kidney fibrosis, cardiac fibrosis, and myelofibrosis.

Exosomal let-7i-5p from three-dimensional cultured human umbilical cord mesenchymal stem cells inhibits fibroblast activation in silicosis through targeting TGFBR1

Silicosis of pulmonary fibrosis (PF) is related to long-term excessive inhalation of silica. The activation of fibroblasts into myofibroblasts is the main terminal effect leading to lung fibrosis, which is of great significance to the study of the occurrence and development of silicosis fibrosis and its prevention and treatment. Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSC-Exos) are considered to be a potential therapy of silica-induced PF, however, their exact mechanism remains unknown. Therefore, this study aims to explore whether hucMSC-Exos affect the activation of fibroblasts to alleviate PF. In this study, a three-dimensional (3D) method was applied to culture hucMSCs and MRC-5 cells (human embryonic lung fibroblasts), and exosomes were isolated from serum-free media, identified by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM) and Western blotting analysis. Then, the study used an animal model of silica-induced PF to observe the effects of hucMSC-Exos and MRC-5-Exos on activation of fibroblasts. In addition, the activation of fibroblasts was analyzed by Western blotting analysis, wound healing, and migration assay with the treatment of hucMSC-Exos and MRC-5-Exos in NIH-3T3 cells (mouse embryonic fibroblasts). Furthermore, differential expression of microRNAs (DE miRNAs) was measured between hucMSCs-Exos and MRC-5-Exos by high throughput sequence. HucMSC-Exos inhibited the activation of fibroblasts in mice and NIH-3T3 cells. Let-7i-5p was significantly up-regulated in hucMSCs-Exos compared to MRC-5-Exos, which was related to silica-induced PF. Let-7i-5p of hucMSCs-Exos was responsible for the activation of fibroblasts by targeting TGFBR1. Meanwhile, Smad3 was also an important role in the activation of fibroblasts. The study demonstrates that hucMSCs-Exos act as a mediator that transfers let-7i-5p to inhibit the activation of fibroblasts, which alleviates PF through the TGFBR1/Smad3 signaling pathway. The mechanism has potential value for the treatment of silica-induced PF.

miR‑200b upregulation promotes migration of BEAS‑2B cells following long‑term exposure to cigarette smoke by targeting ETS1

Cigarette smoking is the leading cause of all histological types of lung cancer, and the role that microRNAs (miRNAs) serve in its pathogenesis is being increasingly recognized. The aim of the present study was to investigate the role of miR‑200b on migration in cigarette smoke‑induced malignant transformed cells. In the present study, miR‑200b expression was found to be increased in cigarette smoke (CS)‑exposed BEAS‑2B cells, lung cancer cell lines and tumor tissue samples. Using wound healing and Transwell migration assays, the migratory ability was shown to be increased in miR‑200b‑overexpressing cells, whereas miR‑200b knockdown resulted in reduced migration. Additionally, the expression of E‑Cadherin was downregulated, whereas that of N‑Cadherin was upregulated in miR‑200b mimic‑transfected cells, suggesting an increase in epithelial‑mesenchymal transition. Downstream, using four target gene prediction tools, six target genes of miR‑200b were predicted, amongst which, ETS proto‑oncogene 1 transcription factor (ETS1) was shown to be significantly associated with tumor invasion depth and negatively associated with miR‑200b expression. The interaction between miR‑200b and ETS1 was confirmed using a dual‑luciferase reporter assay. Using rescue experiments, the increased migratory ability of the miR‑200b‑overexpressing cells was reversed by ETS1 overexpression. In summary, this study showed that miR‑200b overexpression serves a carcinogenic role and promotes the migration of BEAS‑2B cells following long‑term exposure to CS by targeting ETS1.

A Review of Platelet-Activating Factor As a Potential Contributor to Morbidity and Mortality Associated with Severe COVID-19

The precise mechanisms of pathology in severe COVID-19 remains elusive. Current evidence suggests that inflammatory mediators are responsible for the manifestation of clinical symptoms that precedes a fatal response to infection. This review examines the nature of platelet activating factor and emphasizes the similarities between the physiological effects of platelet activating factor and the clinical complications of severe COVID-19.

ROS‑mediated hypomethylation of PRDX5 promotes STAT3 binding and activates the Nrf2 signaling pathway in NSCLC

Deoxyribonucleic acid (DNA) epigenetic modification has been linked to specific sequences of CpG islands and plays roles in the progression of lung cancer. In this study, it was found that peroxiredoxin‑5 (PRDX5) was highly expressed in non‑small cell lung cancer (NSCLC) tissues; however, its specific regulatory mechanisms and functions in NSCLC remain unknown. The present study therefore explored the regulatory mechanism of PRDX5 under conditions of oxidative stress (OS) in NSCLC. The results revealed that 79 of 121 NSCLC patients exhibited demethylation in the PRDX5 promoter region, which was related to the tumor, node and metastasis (TNM) stage (P=0.027). PRDX5 messenger ribonucleic acid (mRNA) expression positively correlated with the demethylation status of the promoter region. The results of bisulfite sequencing polymerase chain reaction (BSP) revealed lower demethylation frequencies in H1299 cells treated with 0 µM H2O2, but maximum demethylation following treatment with 100 µM H2O2. Using chromatin immunoprecipitation (ChIP) and luciferase detection assays, the effective binding of STAT3 to the transcriptional binding sites of the PRDX5 promoter region was confirmed (2 sites confirmed: Site 1, ‑444 to ‑434 bp; and site 4, ‑1,417 to ‑1,407 bp). STAT3 knockdown significantly decreased the protein expression of PRDX5, while the overexpression of STAT3 significantly increased the protein levels of PRDX5. When PRDX5 was overexpressed in lung cancer cells under conditions of OS, the levels of the epithelial‑mesenchymal transition (EMT) biomarkers, E‑cadherin and vimentin, were significantly decreased and increased, respectively. By contrast, PRDX5 knockdown resulted in significantly increased E‑cadherin and decreased vimentin protein expression levels. Ultimately, when PRDX5‑small interfering RNA (siRNA) or pcDNA3.1‑PRDX5 expression vector were constructed and transfected into H1299 cells pre‑treated with 100 µM H2O2, the nuclear factor (erythroid‑derived 2)‑like 2 (Nrf2) signaling pathway was inhibited or activated. All these results suggested that the reactive oxygen species (ROS)‑mediated hypomethylation of PRDX5 enhanced STAT3 binding affinity with the promoter region, and resulted in the promotion of cell migration and invasion, as well as in the activation of the Nrf2 signaling pathway in NSCLC. The demethylation status of the PRDX5 promoter may thus be used as an epigenetic biomarker in NSCLC. STAT3/PRDX5 signaling may also prove to be a potential strategy for the treatment of this type of cancer.

Association between changes in the mRNA expression of platelet-activating factor receptor in peripheral blood mononuclear cells and progression of diabetic nephropathy

Introduction

Several studies have recently pointed out the role of many inflammatory mediators in the progression of diabetes complications. We had previously demonstrated that mRNA expression of platelet-activating factor receptor (PAFR) in peripheral blood mononuclear cells (PBMCs) was associated with urinary albumin to creatinine ratio (ACR) and forearm flow-mediated dilatation in patients with type 2 diabetes. In an attempt to elucidate this association, patients were followed up for 1 year.

Materials and methods

We recruited 95 patients from the hospital outpatient clinic, among whom 86 were followed up for 1 year (normoalbuminuria: 40 patients, microalbuminuria: 25 patients, macroalbuminuria: 21 patients). We then measured their baseline and 12 month characteristics and collected blood samples to extract PBMCs and measure gene expressions.

Results

Despite higher mRNA expression of PAFR in PBMCs among patients with macroalbuminuria, the rise in its value was not associated with biomarkers of nephropathy, while baseline values were not associated with progression of nephropathy. Moreover, changes in mRNA expression of PAFR were correlated with changes in ACR in all patients (r = 0.225, p = 0.037) and estimated glomerular filtration rate in patients with macroalbuminuria (r =  - 0.438, p = 0.047) during the follow-up period.

Conclusion

Our findings indicate that even though no causal relationship exists between diabetic nephropathy and elevated expression of PAFR in PBMCs, their close association signifies the presence of another common mechanism that could induce both events. Given these findings, the PAF/PAFR interaction could clarify corresponding mechanisms involved in diabetic complications.

STAT3 Targets ERR-α to Promote Epithelial-Mesenchymal Transition, Migration, and Invasion in Triple-Negative Breast Cancer Cells

STAT3 is constitutively activated in many malignant tumor types and plays an important role in multiple aspects of cancer aggressiveness. In this study, we found that estrogen-related receptor α (ERR-α) correlating with STAT3 was highly expressed in triple-negative breast cancer (TNBC) cell lines and tissues, which was associated with both the pathologic stage and prognosis of patients with TNBC. In vitro studies showed that ERR-α promoted TNBC cell migration and invasion, which was regulated by STAT3. Phosphorylated STAT3 (p-STAT3, Tyr 705) could bind to the promotor of ERR-α, and activate its transcription, which was suggested by luciferase assay and chromatin immunoprecipitation assay. We also found that ERR-α was the key target gene regulated by STAT3 in promoting epithelial-mesenchymal transition (EMT), migration, and invasion. ERR-α upregulated the expression of ZEB1, N-cadherin, and vimentin while downregulated the expression of E-cadherin. Furthermore, in vivo studies showed that ERR-α could increase the metastasis ability of TNBC. Our finding demonstrated that ERR-α was a direct regulatory gene target of p-STAT3, which was enriched for processes involving invasion and metastasis in TNBC and provided insight into TNBC pathogenesis, as well as a potential therapeutic option against TNBC metastasis. IMPLICATIONS: Our research first showed that p-STAT3 (Tyr 705) could bind to the promotor region of ERR-α and promote EMT in TNBC by ZEB1 pathways, thus providing a potential clinical target for TNBC.

Systemic Platelet-Activating Factor-Receptor Agonism Enhances Non-Melanoma Skin Cancer Growth

Platelet-activating factor-receptor (PAF-R) agonists are pleiotropic lipid factors that influence multiple biological processes, including the induction and resolution of inflammation as well as immunosuppression. PAF-R agonists have been shown to modulate tumorigenesis and/or tumor growth in various skin cancer models by suppressing either cutaneous inflammation and/or anti-tumoral adaptive immunity. We have previously shown that a chronic systemic PAF-R agonist administration of mice enhances the growth of subcutaneously implanted melanoma tumors. Conversely, chronic topical applications of a PAF-R agonist suppressed non-melanoma skin cancer (NMSC) in a topical chemical carcinogenesis model (dimethylbenz[a]anthracene/phorbol 12-myristate 13-acetate (DMBA/PMA)) in-part via anti-inflammatory effects. These results indicate that the context of PAF-R agonist exposure via either chronic cutaneous or systemic administration, result in seemingly disparate effects on tumor promotion. To further dissect the contextual role of PAF-R agonism on tumorigenesis, we chronically administered systemic PAF-R agonist, carbamoyl-PAF (CPAF) to mice under a cutaneous chemical carcinogenesis protocol, recently characterized to initiate both NMSC and melanocytic nevus formation that can progress to malignant melanoma. Our results showed that while systemic CPAF did not modulate melanocytic nevus formation, it enhanced the growth of NMSC tumors.

UPLC/Q-TOFMS-Based Metabolomics Approach to Reveal the Protective Role of Other Herbs in An-Gong-Niu-Huang Wan Against the Hepatorenal Toxicity of Cinnabar and Realgar

An-Gong-Niu-Huang Wan (AGNH) is a well-known traditional Chinese medicine (TCM) recipe containing cinnabar (HgS) and realgar (As₂S₂). However, the application of AGNH is limited by the hepato- and nephrotoxicity of cinnabar and realgar. It should be noted that cinnabar and realgar in AGNH are not used alone, but rather combined with other herbs as formula to use. In this study, the protective effects and mechanisms of the other herbs in AGNH against the hepatorenal toxicity induced by cinnabar and realgar were investigated. The combination use of the other herbs in AGNH alleviated inflammatory cell infiltration and damage in the liver and kidney and restored the disturbed serum metabolic profile induced by cinnabar and realgar insults. By UPLC/Q-TOFMS combined with pattern recognition approaches, we identified 41 endogenous metabolites in the sera of mice that were related to the hepatorenal toxicity of cinnabar and realgar, 36 of which were restored to normal levels when various kinds of herbs were combined as compound recipe. These metabolites function as modulators in inflammation-associated glycerophospholipid, arachidonic acid, linoleic acid, sphingolipid, and ether lipid metabolic pathways. Notably, lysophosphatidylcholines (LysoPCs) were the most elevated among all of the metabolites detected after cinnabar and realgar treatment, while these LysoPCs did not show overt differences between the AGNH and saline control groups, which was associated with relatively unaffected or even up-regulated expression of lysophosphatidylcholine acyltransferase 1 (LPCAT1) and autotaxin (ATX). These findings indicated that other herbs in AGNH could have a protective effect against cinnabar- and realgar-induced hepatic and renal damage via modulating the disordered homeostasis of the glycerophospholipid, arachidonic acid, linoleic acid, ether lipid, and sphingolipid metabolism.

Inflammation, not Cholesterol, Is a Cause of Chronic Disease

Since the Seven Countries Study, dietary cholesterol and the levels of serum cholesterol in relation to the development of chronic diseases have been somewhat demonised. However, the principles of the Mediterranean diet and relevant data linked to the examples of people living in the five blue zones demonstrate that the key to longevity and the prevention of chronic disease development is not the reduction of dietary or serum cholesterol but the control of systemic inflammation. In this review, we present all the relevant data that supports the view that it is inflammation induced by several factors, such as platelet-activating factor (PAF), that leads to the onset of cardiovascular diseases (CVD) rather than serum cholesterol. The key to reducing the incidence of CVD is to control the activities of PAF and other inflammatory mediators via diet, exercise, and healthy lifestyle choices. The relevant studies and data supporting these views are discussed in this review.

LncRNA PFL contributes to cardiac fibrosis by acting as a competing endogenous RNA of let-7d

Rationale: Cardiac fibrosis is associated with various cardiovascular diseases and can eventually lead to heart failure. Dysregulation of long non-coding RNAs (lncRNAs) has recently been recognized as one of the key mechanisms involved in cardiac diseases. However, the potential roles and underlying mechanisms of lncRNAs in cardiac fibrosis have not been explicitly delineated. Methods and Results: Using a combination of in vitro and in vivo studies, we identified a lncRNA NONMMUT022555, which is designated as a pro-fibrotic lncRNA (PFL), and revealed that PFL is up-regulated in the hearts of mice in response to myocardial infarction (MI) as well as in the fibrotic cardiac fibroblasts (CFs). We found that knockdown of PFL by adenoviruses carrying shRNA attenuated cardiac interstitial fibrosis and improved ejection fraction (EF) and fractional shortening (FS) in MI mice. Further study showed that forced expression of PFL promoted proliferation, fibroblast-myofibroblast transition and fibrogenesis in mice CFs by regulating let-7d, whereas silencing PFL mitigated TGF-β1-induced myofibroblast generation and fibrogenesis. More importantly, PFL acted as a competitive endogenous RNA (ceRNA) of let-7d, as forced expression of PFL reduced the expression and activity of let-7d. Moreover, let-7d levels were decreased in the MI mice and in fibrotic CFs. Inhibition of let-7d resulted in fibrogenesis in CFs, whereas forced expression of let-7d abated fibrogenesis through targeting platelet-activating factor receptor (Ptafr). Furthermore, overexpression of let-7d by adenoviruses carrying let-7d precursor impeded cardiac fibrosis and improved cardiac function in MI mice. Conclusion: Taken together, our study elucidated the role and mechanism of PFL in cardiac fibrosis, indicating the potential role of PFL inhibition as a novel therapy for cardiac fibrosis.

mRNA expression of platelet activating factor receptor (PAFR) in peripheral blood mononuclear cells is associated with albuminuria and vascular dysfunction in patients with type 2 diabetes

AIMS

Renal dysfunction in addition to diabetes is a serious risk factor for cardiovascular events. We hypothesized that some of the changes in gene expression in blood cells cause renal dysfunction and macrovascular disease through impaired endothelial function. This study aimed to define which changes in gene expression in peripheral blood mononuclear cells (PBMCs) are related to renal function parameters and endothelial function of large arteries in patients with type 2 diabetes mellitus (T2DM).

METHODS

We recruited 95 patients with T2DM. After matching for gender, age, BMI and HbA1c levels, the patient cohort included 42 with normoalbuminuria, 28 with microalbuminuria, and 25 with macroalbuminuria. All patients in the three groups were assessed for urinary albumin to creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), flow-mediated dilatation (FMD), and mRNA expression in PBMCs.

RESULTS

The mRNA expression of platelet activating factor receptor (PAFR) differed most markedly between the three groups and was significantly higher in the macroalbuminuric group (p < 0.001 vs. normoalbuminuric group; p < 0.05 vs. microalbuminuric group). PAFR mRNA expression significantly correlated with log transformed ACR (ρ = 0.424, p < 0.001) but not eGFR. PAFR mRNA expression also had a significant negative correlation with FMD (ρ = -0.379, p < 0.001). Furthermore, the prevalence of macrovascular complications, particularly stroke, was significantly higher in patients with elevated PAFR mRNA expression in PBMCs.

CONCLUSIONS

PAFR overexpression in PBMCs may link diabetic nephropathy to macroangiopathy through impairment of endothelial function in patients with T2DM.

Epithelial-mesenchymal transition (EMT): A biological process in the development, stem cell differentiation, and tumorigenesis

The lineage transition between epithelium and mesenchyme is a process known as epithelial-mesenchymal transition (EMT), by which polarized epithelial cells lose their adhesion property and obtain mesenchymal cell phenotypes. EMT is a biological process that is often involved in embryogenesis and diseases, such as cancer invasion and metastasis. The EMT and the reverse process, mesenchymal-epithelial transition (MET), also play important roles in stem cell differentiation and de-differentiation (or reprogramming). In this review, we will discuss current research progress of EMT in embryonic development, cellular differentiation and reprogramming, and cancer progression, all of which are representative models for researches of stem cell biology in normal and in diseases. Understanding of EMT and MET may help to identify specific markers to distinguish normal stem cells from cancer stem cells in future.

Tracing the dynamics of gene transcripts after organismal death

In life, genetic and epigenetic networks precisely coordinate the expression of genes-but in death, it is not known if gene expression diminishes gradually or abruptly stops or if specific genes and pathways are involved. We studied this by identifying mRNA transcripts that apparently increase in relative abundance after death, assessing their functions, and comparing their abundance profiles through postmortem time in two species, mouse and zebrafish. We found mRNA transcript profiles of 1063 genes became significantly more abundant after death of healthy adult animals in a time series spanning up to 96 h postmortem. Ordination plots revealed non-random patterns in the profiles by time. While most of these transcript levels increased within 0.5 h postmortem, some increased only at 24 and 48 h postmortem. Functional characterization of the most abundant transcripts revealed the following categories: stress, immunity, inflammation, apoptosis, transport, development, epigenetic regulation and cancer. The data suggest a step-wise shutdown occurs in organismal death that is manifested by the apparent increase of certain transcripts with various abundance maxima and durations.

Contribution of the platelet activating factor signaling pathway to cerebral microcirculatory dysfunction during experimental sepsis by ExoU producing Pseudomonas aeruginosa

Intravital microscopy was used to assess the involvement of ExoU, a Pseudomonas aeruginosa cytotoxin with phospholipase A2 activity, in dysfunction of cerebral microcirculation during experimental pneumosepsis. Cortical vessels from mice intratracheally infected with low density of the ExoU-producing PA103 P. aeruginosa strain exhibited increased leukocyte rolling and adhesion to venule endothelium, decreased capillar density and impaired arteriolar response to vasoactive acetylcholine. These phenomena were mediated by the platelet activating factor receptor (PAFR) pathway because they were reversed in mice treated with a PAFR antagonist prior to infection. Brains from PA103-infected animals exhibited a perivascular inflammatory infiltration that was not detected in animals infected with an exoU deficient mutant or in mice treated with the PAFR antagonist and infected with the wild type bacteria. No effect on brain capillary density was detected in mice infected with the PAO1 P. aeruginosa strain, which do not produce ExoU. Finally, after PA103 infection, mice with a targeted deletion of the PAFR gene exhibited higher brain capillary density and lower leukocyte adhesion to venule endothelium, as well as lower increase of systemic inflammatory cytokines, when compared to wild-type mice. Altogether, our results establish a role for PAFR in mediating ExoU-induced cerebral microvascular failure in a murine model of sepsis.

Effect of bone morphogenic protein-7 on the expression of epithelial-mesenchymal transition markers in silicosis model

This study presented the effect of bone morphogenic protein-7 (BMP-7) inhibiting epithelial-mesenchymal transition (EMT) in silicosis model. In vivo, Wistar rats were exposed to silica by intratracheal instillation. Seven days later rats were treated with BMP-7. Rats were sacrificed at 15 and 30days after exposure of silica. The results demonstrated vimentin expression was down-regulated; and E-cadherin was up-regulated after intervention with BMP-7. The TGF-β expression and phosphorylation-p38 were lower in BMP-7 treated group than in silica group. In vitro, p38 MAPK/Snail signaling pathway was involved in the occurrence of EMT in A549 cells treated by silica. EMT was inhibited by BMP-7. The data showed BMP-7 inhibited EMT induced by silica associated with inhibition of p38 MAPK/Snail pathway.

The role of platelet-activating factor in mesangial pathophysiology

Platelet-activating factor (PAF) is a powerful proinflammatory mediator that displays an exceedingly diverse spectrum of biological effects. Importantly, PAF is shown to participate in a broad range of pathologic conditions. This review focuses on the role that PAF plays specifically in the pathophysiology of the kidney, the organ that is both a source and a target of PAF. Renal mesangial cells are responsible for glomerular PAF generation and, ultimately, are the victims of its excessive production. Mesangial pathology is widely acknowledged to reflect glomerular damage, which culminates in glomerulosclerosis and proteinuria. Therefore, modulation of mesangial cell responses would offer a pathophysiology-based therapeutic approach to prevent glomerular injury. However, the currently available therapeutic modalities do not allow for targeted intervention into these processes. A more profound understanding of the mechanisms that govern PAF metabolism and signaling in mesangial cells is important, because it could facilitate the quest for improved therapies for renal patients on the basis of PAF as a drug target.

DNA methylation in cardiac fibrosis: new advances and perspectives

Cardiac fibrosis is characterized by net accumulation of extracellular matrix (ECM) proteins in the cardiac interstitium, and contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. More specifically, cardiac fibroblasts are activated by a variety of pathological stimuli, thereby undergoing proliferation, differentiation to myofibroblasts, and production of various cytokines and ECM proteins. Thus, understanding the biological processes of cardiac fibroblasts will provide novel insights into the underlying mechanisms of cardiac fibrosis. DNA methylation is an important epigenetic mechanism, which often occurs in response to environmental stimuli and is crucial in regulating gene expression. The aberrant methylation of CpG island promoters of selected genes is the prominent epigenetic mechanism by which gene transcription can be effectively silenced. Aberrant hypermethylation of a few selected genes such as RASSF1A plays an important role in facilitating fibrotic fibroblast activation and in driving fibrosis. In this review we will discuss the mechanisms of DNA methylation and their implications for cardiac fibroblasts activation and fibrosis. Control of DNA methylation may serve as a new strategy for anti-fibrotic therapy.

Lysyl oxidase genetic variants affect gene expression in cervical cancer

Lysyl oxidase (LOX) is a copper-dependent amine oxidase that plays important roles in the homeostasis of tumors. The aim of this study was to investigate the association between LOX polymorphisms and cervical cancer, and the effect of these polymorphisms on gene expression. We evaluated two polymorphisms of LOX, rs1800449G/A (G473A) and rs2278226C/G, in 262 cervical cancer cases and 298 healthy controls in the Chinese population. Results showed that the prevalence of rs1800449AA genotype was significantly increased in cases than in controls (p=0.004). Individuals who carried the rs1800449A allele had a 1.56-fold increased risk for cervical cancer than those with the rs1800449G allele (p=0.003). The rs2278226CG genotype also revealed a significantly higher proportion in cases (20.6%) than in controls (7.7%, p<0.001). Interestingly, when analyzing these two polymorphisms with the serum level of LOX, we identified that cervical cancer patients carrying the rs2278226CG genotype had a significantly elevated level of LOX than those with rs2278226CC wild type, whereas the same phenomenon was not observed in controls. The rs1800449 polymorphism did not affect the LOX serum level in either controls or patients. These results suggest that the polymorphisms in the LOX gene may be involved in the development of cervical cancer through various mechanisms.

Sedum sarmentosum Bunge extract exerts renal anti-fibrotic effects in vivo and in vitro

AIMS

Sedum sarmentosum Bunge, a traditional Chinese herbal medicine, has a wide range of clinical effects, including anti-oxidation, anti-inflammation, and anti-cancer properties. In this study, we determined whether S. sarmentosum Bunge Extract (SSBE) has anti-fibrotic effects on renal tissues.

MAIN METHODS

We investigated the effects of SSBE on aristolochic acid (AA)-induced injury to renal tubular epithelial cells (RTECs) in vitro and unilateral ureteral obstruction (UUO)-induced renal fibrosis in vivo by evaluating epithelial-to-mesenchymal transition (EMT) and the accumulation of extracellular matrix (ECM) components. Furthermore, we examined the expression levels of TGF-β1 and its receptor.

KEY FINDINGS

In cultured RTECs (NRK-52E), AA promoted renal EMT and ECM accumulation by up-regulating the expression of mesenchymal markers and ECM components and by down-regulating the expression of epithelial markers. In addition, AA induced an imbalance between MMP-2 and TIMP-2 and enhanced expression of TGF-β1 and its receptor. SSBE treatment significantly inhibited AA-induced TGF-β1 expression and prevented the induction of EMT and deposition of ECM. In the UUO rats, tubular injury and interstitial fibrosis were obviously increased. SSBE administration protected renal function, as indicated by reduced serum creatinine levels, and alleviated renal interstitial fibrosis. These anti-fibrotic effects were associated with a reduction in TGF-β1 expression and inhibition of EMT and ECM accumulation.

SIGNIFICANCE

These findings suggest that SSBE may have therapeutic potential for fibrotic kidney diseases.