NLRC5 regulates TGF-β1-induced proliferation and activation of hepatic stellate cells during hepatic fibrosis

Mitochondrial DNA (mtDNA) accelerates oxygen-glucose deprivation-induced injury of proximal tubule epithelia cell via inhibiting NLRC5

The high morbidity and mortality associated with acute kidney injury (AKI) are global health concerns. AKI is commonly attributed to ischemia/reperfusion injury (IRI), a condition characterized by activation of inflammatory responses and mitochondrial dysfunction. Nonetheless, mitochondrial DNA (mtDNA) has the potential to induce renal IRI. This study aimed to elucidate the mechanism and function of mtDNA in HK-2 cells that had been exposed to oxygen-glucose deprivation/reperfusion (OGD/R) and in renal IRI mice. OGD/R was discovered to induce an increase in the amount of mtDNA in HK-2 cells. Moreover, our study demonstrated that mtDNA facilitated cellular apoptosis and inflammation in vivo and in vitro. Given the potential role of inflammation in OGD/R, we investigated the effect of mtDNA on various signaling pathways associated with inflammation. Western blot analysis demonstrated that mtDNA significantly upregulated NLRC5/TAP1 signaling. Furthermore, the upregulation of NLRC5 and TAP1 expression induced by mtDNA was reversed when NLRC5 was inhibited. It is worth mentioning that the loss of NLRC5 effectively nullified the beneficial effects of mtDNA on inflammation and cell apoptosis induced by OGD/R. In addition, in renal IRI mice, mtDNA treatment also aggravated inflammation and kidney damage, and increased the NLRC5 levels in kidney tissues. These results suggested that NLRC5 acts as an intermediary between mtDNA and the pathogenicity of renal IRI. In summary, this study provides evidence that mtDNA promotes apoptosis and inflammation in OGD/R treated HK-2 cells and renal IRI mice through upregulating NLRC5 levels.

Targeting NLRC5 in cardiomyocytes protects postinfarction cardiac injury by enhancing autophagy flux through the CAVIN1/CAV1 axis

NOD-like receptor (NLR) family proteins are implicated in various cardiovascular diseases. However, the precise role of NLRC5, the largest member of this family, in myocardial infarction (MI) remains poorly understood. This study reveals that NLRC5 is upregulated in the hearts of both patients with MI and MI mice. Silencing NLRC5 in cardiomyocytes impairs cardiac repair and functional recovery, while its overexpression enhances these processes. Furthermore, NLRC5 promotes autophagy in cardiomyocytes, and its protective effects are diminished upon autophagy inhibition. Mechanistically, NLRC5 interacts with CAVIN1, facilitating its degradation and subsequent downregulation of CAV1, which in turn increases the expression of the ATG12-ATG5 complex to stimulate autophagy. Conversely, CAV1 overexpression partially suppresses autophagy and attenuates the improvements in cardiac function observed in NLRC5-overexpressing MI hearts. This study highlights the critical regulatory role of NLRC5 in modulating cardiomyocyte autophagy flux, suggesting that NLRC5 activation may represent a promising therapeutic strategy for MI.

New insights into the structure domain and function of NLR family CARD domain containing 5

NOD-like receptor family CARD domain-containing 5 (NLRC5) is a major transcriptional coactivator of MHC class I genes. NLRC5 is the largest member of the NLR family and contains three domains: an untypical caspase recruitment domain (uCARD), a central nucleotide-binding and oligomerization domain (NOD or NACHT), and a leucine-rich repeat (LRR) domain. The functional variability of NLRC5 has been attributed to its different domain interactions with specific ligands in different cell types. In this review, we address the molecular mechanisms and their implications in multiple microenvironments based on the different functional domains of NLRC5.

Expression and clinical significance of NLRC5 in hepatocellular carcinoma

NLRC5, the largest member of the nucleotide-binding and oligomerization domain (NOD)-like receptor (NLR) family, has been reported to participate in the regulation of immune function and is associated with chronic inflammatory diseases. However, the biological function of NLRC5 in hepatocellular carcinoma (HCC) has not been fully demonstrated. The aim of this study is to evaluate NLRC5 expression in the tumor tissues of HCC patients undergoing surgical treatment, assess its prognostic value, and explore its relationship with critical immune-related molecules within the tumor microenvironment. A total of 100 patients with hepatitis B virus-associated HCC receiving surgical treatment were enrolled in the study. Immunohistochemical results were obtained by scoring the intensity of cellular staining and the percentage of positive cells in the tissue sections. The association between NLRC5 expression levels and the main clinicopathological factors was analyzed by Chi-square test method. The prognostic values were analyzed by COX regression model and the Kaplan-Meier survival curve. Receiver operating characteristic (ROC) curve analysis was performed to assess the predictive performance of NLRC5 in postoperative patients with HCC. IHC showed that high expression of NLRC5 was observed in 67% of HCC tissue samples. Chi-square test showed that NLRC5 was a risk factor associated with tumor number, satellite nodule, and envelope invasion. Kaplan-Meier survival curves and COX survival analysis showed that high expression of NLRC5 was significantly associated with decreased overall survival (OS) in HCC patients (HR = 1.79, 95% CI 1.03-3.12, p = .041). However, univariate logistic regression analysis revealed that NLRC5 showed positive relationship with GZMB and CD8α suggesting its role in immune escape of HCC. ROC curve analysis showed that the combination of tumor number, envelope invasion, and NLRC5 expression (area under the curve = 0.824, sensitivity = 77.30%, specificity = 82.4%) can more accurately evaluate the prognosis of HCC patients compared to the combination of only tumor number and envelope invasion (area under the curve = 0.690, sensitivity = 43.9%, specificity = 94.1%).NLRC5 plays a crucial role in progression of HCC and can be considered as a potential prognostic and predictive biomarker. Targeting NLRC5 may provide an attractive therapeutic approach for HCC.

Gene coexpression network analysis reveals the genes and pathways in pectoralis major muscle and liver associated with wooden breast in broilers

Wooden breast (WB) is a myopathy mainly affecting pectoralis major (PM) muscle in modern commercial broiler chickens, causing enormous economic losses in the poultry industry. Recent studies have observed hepatic and PM muscle injury in broilers affected by WB, but the relationships between WB and the 2 tissues are mostly unclear. In the current study, the RNA-seq raw data of PM muscle and liver were downloaded from GSE144000, and we constructed the gene coexpression networks of PM muscle and liver to explore the relationships between WB and the 2 tissues using the weighted gene coexpression network analysis (WGCNA) method. Six and 2 gene coexpression modules were significantly correlated with WB in the PM muscle and liver networks, respectively. TGF-beta signaling, Toll-like receptor signaling and mTOR signaling pathways were significantly enriched in the genes within the 6 gene modules of PM muscle network. Meanwhile, mTOR signaling pathway was significantly enriched in the genes within the 2 gene modules of liver network. In the consensus gene coexpression network across the 2 tissues, salmon module (r = -0.5 and p = 0.05) was significantly negatively correlated with WB, in which Toll-like receptor signaling, apoptosis, and autophagy pathways were significantly enriched. The genes related with the 3 pathways, myeloid differentiation primary response 88 (MYD88), interferon regulatory factor 7 (IRF7), mitogen-activated protein kinase 14 (MAPK14), FBJ murine osteosarcoma viral oncogene homolog (FOS), jun proto-oncogene (JUN), caspase-10, unc-51 like autophagy activating kinase 2 (ULK2) and serine/threonine kinase 11 (LKB1), were identified in salmon module. In this current study, we found that the signaling pathways related with cell inflammation, apoptosis and autophagy might influence WB across 2 tissues in broilers.

The role of long noncoding RNA MEG3 in fibrosis diseases

Fibrosis is a prevalent pathological condition observed in various organs and tissues. It primarily arises from the excessive and abnormal accumulation of the extracellular matrix, resulting in the structural and functional impairment of tissues and organs, which can culminate in death. Many forms of fibrosis, including liver, cardiac, pulmonary, and renal fibrosis, are considered irreversible. Maternally expressed gene 3 (MEG3) is an imprinted RNA gene. Historically, the downregulation of MEG3 has been linked to tumor pathogenesis. However, recent studies indicate an emerging association of MEG3 with fibrotic diseases. In this review, we delve into the current understanding of MEG3's role in fibrosis, aiming to shed light on the molecular mechanisms of fibrosis and the potential of MEG3 as a novel therapeutic target.

Dietary intervention reverses molecular markers of hepatocellular senescence in the GAN diet-induced obese and biopsy-confirmed mouse model of NASH

BACKGROUND

Hepatocellular senescence may be a causal factor in the development and progression of non-alcoholic steatohepatitis (NASH). The most effective currently available treatment for NASH is lifestyle intervention, including dietary modification. This study aimed to evaluate the effects of dietary intervention on hallmarks of NASH and molecular signatures of hepatocellular senescence in the Gubra-Amylin NASH (GAN) diet-induced obese (DIO) and biopsy-confirmed mouse model of NASH.

METHODS

GAN DIO-NASH mice with liver biopsy-confirmed NASH and fibrosis received dietary intervention by switching to chow feeding (chow reversal) for 8, 16 or 24 weeks. Untreated GAN DIO-NASH mice and chow-fed C57BL/6J mice served as controls. Pre-to-post liver biopsy histology was performed for within-subject evaluation of NAFLD Activity Score and fibrosis stage. Terminal endpoints included blood/liver biochemistry, quantitative liver histology, mitochondrial respiration and RNA sequencing.

RESULTS

Chow-reversal promoted substantial benefits on metabolic outcomes and liver histology, as demonstrated by robust weight loss, complete resolution of hepatomegaly, hypercholesterolemia, elevated transaminase levels and hepatic steatosis in addition to attenuation of inflammatory markers. Notably, all DIO-NASH mice demonstrated ≥ 2 point significant improvement in NAFLD Activity Score following dietary intervention. While not improving fibrosis stage, chow-reversal reduced quantitative fibrosis markers (PSR, collagen 1a1, α-SMA), concurrent with improved liver mitochondrial respiration, complete reversal of p21 overexpression, lowered γ-H2AX levels and widespread suppression of gene expression markers of hepatocellular senescence.

CONCLUSIONS

Dietary intervention (chow reversal) substantially improves metabolic, biochemical and histological hallmarks of NASH and fibrosis in GAN DIO-NASH mice. These benefits were reflected by progressive clearance of senescent hepatocellular cells, making the model suitable for profiling potential senotherapeutics in preclinical drug discovery for NASH.

Liver Fibrosis Resolution: From Molecular Mechanisms to Therapeutic Opportunities

The liver is a critical system for metabolism in human beings, which plays an essential role in an abundance of physiological processes and is vulnerable to endogenous or exogenous injuries. After the damage to the liver, a type of aberrant wound healing response known as liver fibrosis may happen, which can result in an excessive accumulation of extracellular matrix (ECM) and then cause cirrhosis or hepatocellular carcinoma (HCC), seriously endangering human health and causing a great economic burden. However, few effective anti-fibrotic medications are clinically available to treat liver fibrosis. The most efficient approach to liver fibrosis prevention and treatment currently is to eliminate its causes, but this approach's efficiency is too slow, or some causes cannot be fully eliminated, which causes liver fibrosis to worsen. In cases of advanced fibrosis, the only available treatment is liver transplantation. Therefore, new treatments or therapeutic agents need to be explored to stop the further development of early liver fibrosis or to reverse the fibrosis process to achieve liver fibrosis resolution. Understanding the mechanisms that lead to the development of liver fibrosis is necessary to find new therapeutic targets and drugs. The complex process of liver fibrosis is regulated by a variety of cells and cytokines, among which hepatic stellate cells (HSCs) are the essential cells, and their continued activation will lead to further progression of liver fibrosis. It has been found that inhibiting HSC activation, or inducing apoptosis, and inactivating activated hepatic stellate cells (aHSCs) can reverse fibrosis and thus achieve liver fibrosis regression. Hence, this review will concentrate on how HSCs become activated during liver fibrosis, including intercellular interactions and related signaling pathways, as well as targeting HSCs or liver fibrosis signaling pathways to achieve the resolution of liver fibrosis. Finally, new therapeutic compounds targeting liver fibrosis are summarized to provide more options for the therapy of liver fibrosis.

NOD-like Receptors-Emerging Links to Obesity and Associated Morbidities

Obesity and its associated metabolic morbidities have been and still are on the rise, posing a major challenge to health care systems worldwide. It has become evident over the last decades that a low-grade inflammatory response, primarily proceeding from the adipose tissue (AT), essentially contributes to adiposity-associated comorbidities, most prominently insulin resistance (IR), atherosclerosis and liver diseases. In mouse models, the release of pro-inflammatory cytokines such as TNF-alpha (TNF-α) and interleukin (IL)-1β and the imprinting of immune cells to a pro-inflammatory phenotype in AT play an important role. However, the underlying genetic and molecular determinants are not yet understood in detail. Recent evidence demonstrates that nucleotide-binding and oligomerization domain (NOD)-like receptor (NLR) family proteins, a group of cytosolic pattern recognition receptors (PRR), contribute to the development and control of obesity and obesity-associated inflammatory responses. In this article, we review the current state of research on the role of NLR proteins in obesity and discuss the possible mechanisms leading to and the outcomes of NLR activation in the obesity-associated morbidities IR, type 2 diabetes mellitus (T2DM), atherosclerosis and non-alcoholic fatty liver disease (NAFLD) and discuss emerging ideas about possibilities for NLR-based therapeutic interventions of metabolic diseases.

Betulinic acid prevents liver fibrosis by binding Lck and suppressing Lck in HSC activation and proliferation

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum japonicum Thunb. ex Murray (Hypericaceae), named 'Tianjihuang' is a traditional Chinese medicine with hepatoprotective, antibacterial, and antitumour effects. Betulinic acid (BA) is its active constituent and has been found to have a number of biological effects, including antiviral, anti-inflammatory, and anti-malarial therapeutic properties. Non-alcoholic fatty liver disease and acute alcoholic liver injury have both been proven to benefit from BA. BA's effects and mechanism on liver fibrosis are still unknown.

AIM OF THE STUDY

The purpose of this study was to explore the influence of BA on lymphocyte-specific protein tyrosine kinase (Lck), a non-receptor Src family kinase, that reduces liver fibrosis by inhibiting the phosphorylation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways through the interaction of Lck and SOCS1.

MATERIALS AND METHODS

A liver fibrosis model was established in vivo with CCl₄ using haematoxylin and eosin (HE) staining, Masson staining, immunohistochemical staining, and immunofluorescence staining. Hepatic stellate cells were induced with transforming growth factor (TGF)-β1 in vitro, using Western blotting, immunofluorescence staining, and a cell scratch assay.

RESULTS

In a CCl₄-induced mouse hepatic fibrosis model and in TGF-β1-activated HSC-T6 cells, BA markedly reduced fibrosis, as demonstrated by the dramatic downregulation of α-smooth muscle actin (α-SMA) and type I collagen alpha-1 (Col1α1) protein levels in vivo and in vitro. BA significantly suppressed the activity and expression of Lck in vitro. Overexpression of Lck may diminish the effect of BA on liver fibrosis. In vitro, BA also greatly increased the expression of suppressor of cytokine signalling 1 (SOCS1) while it considerably inhibited the expression of p-JAK and p-STAT1.

CONCLUSIONS

These findings suggest that BA promotes the expression of SOCS1 by the inhibiting the interaction between Lck and SOCS1, followed by the inhibition of JAK/STAT phosphorylation to prevent the progression of liver fibrosis. Therefore, BA could be used as a promising natural supplement for the treatment of liver fibrosis.

The Mechanism and Regulation of the NLRP3 Inflammasome during Fibrosis

Fibrosis is often the end result of chronic inflammation. It is characterized by the excessive deposition of extracellular matrix. This leads to structural alterations in the tissue, causing permanent damage and organ dysfunction. Depending on the organ it effects, fibrosis can be a serious threat to human life. The molecular mechanism of fibrosis is still not fully understood, but the NLRP3 (NOD-, LRR- and pyrin–domain–containing protein 3) inflammasome appears to play a significant role in the pathogenesis of fibrotic disease. The NLRP3 inflammasome has been the most extensively studied inflammatory pathway to date. It is a crucial component of the innate immune system, and its activation mediates the secretion of interleukin (IL)-1β and IL-18. NLRP3 activation has been strongly linked with fibrosis and drives the differentiation of fibroblasts into myofibroblasts by the chronic upregulation of IL-1β and IL-18 and subsequent autocrine signaling that maintains an activated inflammasome. Both IL-1β and IL-18 are profibrotic, however IL-1β can have antifibrotic capabilities. NLRP3 responds to a plethora of different signals that have a common but unidentified unifying trigger. Even after 20 years of extensive investigation, regulation of the NLRP3 inflammasome is still not completely understood. However, what is known about NLRP3 is that its regulation and activation is complex and not only driven by various activators but controlled by numerous post-translational modifications. More recently, there has been an intensive attempt to discover NLRP3 inhibitors to treat chronic diseases. This review addresses the role of the NLRP3 inflammasome in fibrotic disorders across many different tissues. It discusses the relationships of various NLRP3 activators to fibrosis and covers different therapeutics that have been developed, or are currently in development, that directly target NLRP3 or its downstream products as treatments for fibrotic disorders.

XSSJS inhibits hepatic fibrosis by promoting the mir29b-3p/VEGFA axis in vitro and in vivo

Hepatic pathological angiogenesis (HPA) is the key event of hepatic fibrosis (HF). Xueshisanjia powder (XSSJS), a Chinese herbal compound, is beneficial for alleviating pathological angiogenesis of hepatic tissue. The present study attempts to reveal the effect and mechanism of XSSJS via regulating miR-29b-3p/VEGFA axis against pathological angiogenesis in HF. In in vitro model, human embryonic kidney 293T cells were transfected with miR-29b-3p mimics, whereby the expression of miR-29b-3p was tested by real-time quantitative polymerase chain reaction (RT-qPCR), ensued by Luciferase assay determining the relationship between miR-29b-3p and vascular endothelial cell growth factor A (VEGFA). In addition, miR-29b-3p mimic transfected into the activated hepatic stellate cell T6 (HSC-T6). The Cell-Counting-Kit 8 (CCK8) and 5-Bromodeoxyuridine (BrdU) staining were first utilized to detect the antiproliferative efficiency of XSSJS following the XSSJS compound serum intervention, and then used to observe the expression of transforming growth factor-β (TGF-β), VEGFA, platelet-derived growth factor (PDGF) via RT-PCR, Western blot (WB), and Immunofluorescence (IF) methods. During the in vivo model, XSSJS with boil-free granules were fed to Wistar rats with liver fibrosis caused by intraperitoneal injection of pig serum followed by the transfection of miR-29b-3p adeno-associated virus (AAV). Hematoxylin–Eosin (HE) staining was used for histopathology assessment. The expression of miR-29b-3p, VEGFA, PDGF, TGF-β have been investigated in liver tissue using RT-PCR, WB, IF. The results verified that XSSJS could up-regulate miR-29b-3p and suppress the expression of VEGFA, PDGA, and TGF-β. In mechanism, miR-29b-3p primarily targeted the 3′UTR of VEGFA. In conclusion, XSSJS could modulate miR-29b-3p/VEGFA axis to inhibit the pathological angiogenesis of HF.

Role of Cytokines on the Progression of Liver Fibrosis in Mice Infected with Echinococcus multilocularis

Background

Liver fibrosis is a significant pathological change of Echinococcus multilocularis (E. multilocularis) infection. This study aimed to explore the role of cytokines on the progression of liver fibrosis in mice infected with E. multilocularis.

Methods

Liver histopathological features at 2, 8, 30, 90 and 180 d were quantified by inflammatory severity score. The expression levels of inflammatory cytokines, fibrosis-related cytokines and hepatic cell apoptosis were measured using qRT-PCR and immunohistochemistry.

Results

At the early stage of infection, parasite stimulation triggers the rapid recruitment of immune cells, such as macrophages and neutrophils. These infiltrated immune cells then produce a large number of cytokines, such as iNOS (inducible nitric oxide synthase), a pro-inflammatory cytokine; TGF-β (transforming growth factor) activated HSCs (hepatic stellate cells) to promote the proliferation of fibroblasts and secretion of ECM (extracellular matrix); MMP9 (matrix metalloproteinase 9) degraded basal ECM and facilitated its replacement by a highly dense interstitial matrix. At the middle and late stages of infection, the expression of IL-10 (interleukin-10) with general inhibitory effect was increased. The imbalance of fiber formation and degradation aggravated liver fibrosis. Meanwhile, the whole process of E. multilocularis infection was accompanied by the necrosis and apoptosis of hepatic cells.

Conclusion

Along with the expansion of parasitic infection, dynamic changes in cytokine expression were observed on the liver fibrosis progression, which is helpful to provide some new ideas for the prevention and treatment of liver fibrosis in mice infected with E. multilocularis.

The Potential Role of Cellular Senescence in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) represents an increasing global health burden. Cellular senescence develops in response to cellular injury, leading not only to cell cycle arrest but also to alterations of the cellular phenotype and metabolic functions. In this review, we critically discuss the currently existing evidence for the involvement of cellular senescence in NAFLD in order to identify areas requiring further exploration. Hepatocyte senescence can be a central pathomechanism as it may foster intracellular fat accumulation, fibrosis and inflammation, also due to secretion of senescence-associated inflammatory mediators. However, in some non-parenchymal liver cell types, such as hepatic stellate cells, senescence may be beneficial by reducing the extracellular matrix deposition and thereby reducing fibrosis. Deciphering the detailed interaction between NAFLD and cellular senescence will be essential to discover novel therapeutic targets halting disease progression.

LncRNA MEG3 reverses CCl4-induced liver fibrosis by targeting NLRC5

Liver fibrosis is a persistent pathological repair of chronic liver injury, which is characterized by excessive deposition of collagen-dominated extracellular matrix (ECM). It is well known that hepatic fibrosis can be reversed in the absence of etiology. Studies have shown that long non-coding RNA (Lnc RNA) maternally expressed gene3 (MEG3) has strong effects on the activation of hepatic stellata cells (HSCs). However, the function of MEG3 in the reversal of liver fibrosis has not been studied. In this experiment, we studied the content expression, function, and part of the potential mechanism of MEG3 in reversing liver fibrosis. In in vivo and in vitro models, we found that MEG3 was down-regulated during the formation of liver fibrosis, while it was up-regulated during the reversal of liver fibrosis. Then, it was found that the silencing of MEG3 could gradually restore the activity of the inactivated LX-2 cells, Overexpression of MEG3 can inhibit the activation of LX-2 cells, accelerate the reversal of liver fibrosis. Through catRAPID analysis, it was found that NLR family CARD domain containing 5 (NLRC5) may be a target of MEG3. We found that, after MEG3 silencing, NLRC5 expression was upregulated in LX-2 cells in the reverse phase, while, after MEG3 overexpression, NLRC5 expression was decreased. Further, we verified that MEG3 can target NLRC5 through RNA pull down experiment. Therefore, MEG3 may inhibit the activation of hepatic stellate cells by targeting NLRC5, thus accelerating the reversal of hepatic fibrosis.

NLRC5 Deficiency Deregulates Hepatic Inflammatory Response but Does Not Aggravate Carbon Tetrachloride-Induced Liver Fibrosis

The nucleotide-binding leucine-rich repeat-containing receptor (NLR) family protein-5 (NLRC5) controls NF-κB activation and production of inflammatory cytokines in certain cell types. NLRC5 is considered a potential regulator of hepatic fibrogenic response due to its ability to inhibit hepatic stellate activation in vitro. To test whether NLRC5 is critical to control liver fibrosis, we treated wildtype and NLRC5-deficient mice with carbon tetrachloride (CCl4) and assessed pathological changes in the liver. Serum alanine transaminase levels and histopathology examination of liver sections revealed that NLRC5 deficiency did not exacerbate CCl4-induced liver damage or inflammatory cell infiltration. Sirius red staining of collagen fibers and hydroxyproline content showed comparable levels of liver fibrosis in CCl4-treated NLRC5-deficient and control mice. Myofibroblast differentiation and induction of collagen genes were similarly increased in both groups. Strikingly, the fibrotic livers of NLRC5-deficient mice showed reduced expression of matrix metalloproteinase-3 (Mmp3) and tissue inhibitor of MMPs-1 (Timp1) but not Mmp2 or Timp2. Fibrotic livers of NLRC5-deficient mice had increased expression of TNF but similar induction of TGFβ compared to wildtype mice. CCl4-treated control and NLRC5-deficient mice displayed similar upregulation of Cx3cr1, a monocyte chemoattractant receptor gene, and the Cd68 macrophage marker. However, the fibrotic livers of NLRC5-deficient mice showed increased expression of F4/80 (Adgre1), a marker of tissue-resident macrophages. NLRC5-deficient livers showed increased phosphorylation of the NF-κB subunit p65 that remained elevated following fibrosis induction. Taken together, NLRC5 deficiency deregulates hepatic inflammatory response following chemical injury but does not significantly aggravate the fibrogenic response, showing that NLRC5 is not a critical regulator of liver fibrosis pathogenesis.

Tunicamycin Induces Hepatic Stellate Cell Apoptosis Through Calpain-2/Ca2 +-Dependent Endoplasmic Reticulum Stress Pathway

It has been reported that calpain/caspase-mediated apoptosis induced by endoplasmic reticulum stress (ERS) in hepatic stellate cells (HSCs) by previous studies. At present, the activation of HSC is an important cause of liver fibrosis, and the induction of HSC apoptosis plays an irreplaceable role in reversing liver fibrosis. Therefore, it is of great significance to explore mechanisms of action that can induce HSC apoptosis for the reversal of hepatic fibrosis and the clinical prevention and treatment of hepatic-fibrosis-related diseases such as hepatitis, cirrhosis, and liver cancer. In the current study, we demonstrated that tunicamycin (a novel ERS inducer) can induce the apoptosis of HSCs and increase the concentration of intracellular Ca²⁺ and the expression of ERS protein GRP78, apoptosis protein caspase-12, and Bax, while it can decrease the antiapoptosis protein expression of Bcl-2. Our findings indicate that tunicamycin can induce HSCs apoptosis through calpain-2/Ca²⁺-dependent ERS pathway.

NLRC5: A Potential Target for Central Nervous System Disorders

Nucleotide oligomerization domain-like receptors (NLRs), a class of pattern recognition receptors, participate in the host’s first line of defense against invading pathogenic microorganisms. NLR family caspase recruitment domain containing 5 (NLRC5) is the largest member of the NLR family and has been shown to play an important role in inflammatory processes, angiogenesis, immunity, and apoptosis by regulating the nuclear factor-κB, type I interferon, and inflammasome signaling pathways, as well as the expression of major histocompatibility complex I genes. Recent studies have found that NLRC5 is also associated with neuronal development and central nervous system (CNS) diseases, such as CNS infection, cerebral ischemia/reperfusion injury, glioma, multiple sclerosis, and epilepsy. This review summarizes the research progress in the structure, expression, and biological characteristics of NLRC5 and its relationship with the CNS.

Inflammasomes and Fibrosis

Fibrosis is the final common pathway of inflammatory diseases in various organs. The inflammasomes play an important role in the progression of fibrosis as innate immune receptors. There are four main members of the inflammasomes, such as NOD-like receptor protein 1 (NLRP1), NOD-like receptor protein 3 (NLRP3), NOD-like receptor C4 (NLRC4), and absent in melanoma 2 (AIM2), among which NLRP3 inflammasome is the most studied. NLRP3 inflammasome is typically composed of NLRP3, ASC and pro-caspase-1. The activation of inflammasome involves both "classical" and "non-classical" pathways and the former pathway is better understood. The "classical" activation pathway of inflammasome is that the backbone protein is activated by endogenous/exogenous stimulation, leading to inflammasome assembly. After the formation of "classic" inflammasome, pro-caspase-1 could self-activate. Caspase-1 cleaves cytokine precursors into mature cytokines, which are secreted extracellularly. At present, the "non-classical" activation pathway of inflammasome has not formed a unified model for activation process. This article reviews the role of NLRP1, NLRP3, NLRC4, AIM2 inflammasome, Caspase-1, IL-1β, IL-18 and IL-33 in the fibrogenesis.

NLRC5 alleviated OGD/R-induced PC12-cell injury by inhibiting activation of the TLR4/MyD88/NF-κB pathway

OBJECTIVE

To assess the role of NOD-like receptor C5 (NLRC5; a major NLRC family protein that regulates immunity, inflammation and tissue fibrosis), in cerebral ischemia-reperfusion injury, characterized by inflammation and oxidative damage.

METHODS

Blood NLRC5 levels were assessed in neonates with cerebral ischemia and in healthy controls. A stable PC12 cell line was established that overexpressed or knocked down NLRC5. Inflammatory responses, apoptosis rate and oxidative damage in PC12 cells under oxygen-glucose deprivation/reperfusion (OGD/R) conditions were evaluated using enzyme-linked immunosorbent assay (ELISA), terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) and reactive oxygen species (ROS) assay.

RESULTS

Blood NLRC5 levels were suppressed in neonates with cerebral ischemia. ELISAs showed that NLRC5 suppressed levels of tumour necrosis factor-α, interleukin (IL)-6, IL-1β, ROS and superoxide dismutase in OGD/R-treated PC12 cells. Furthermore, NLRC5 overexpression was associated with reduced apoptosis rate in PC12 cells treated by OGD/R. Overexpression of NLRC5 also inhibited levels of toll-like receptor (TLR)4, myeloid differentiation primary response protein MyD88 (MyD88) and phosphorylated nuclear factor kappa B-transcription factor p65 (NF-κB p-p65) in PC12 cells, and decreased nuclear levels of NF-κB p-p65.

CONCLUSION

NLRC5 alleviated inflammatory responses, oxidative damage and apoptosis in PC12 cells under OGD/R conditions by suppressing activation of the TLR4/MyD88/NF-κB pathway.

NLRC4 gene silencing-dependent blockade of NOD-like receptor pathway inhibits inflammation, reduces proliferation and increases apoptosis of dendritic cells in mice with septic shock

Septic shock is one of the most significant health concerns across the world, involving hypo-perfusion and defects in tissue energy. The current study investigates the role of NLR family CARD domain containing protein 4 (NLRC4) in septic shock-induced inflammatory reactions, lung tissue injuries, and dendritic cell (DC) apoptosis. Septic shock mice models were established by modified cecal ligation and puncture and injected with retroviral vector expressing siRNA-NLRC4. DCs were then isolated and transfected with siRNA-NLRC4. The degree of lung tissue injury, cell cycle distribution, cell apoptosis and cell viability of DCs were assessed. NLRC4 was found to be expressed at high levels in mice with septic shock. NLRC4 silencing inhibited the activation of the NOD-like receptor (NLR) pathway as evidenced by the decreased levels of NOD1, NOD2, RIP2, and NF-κB. In addition, NLRC4 silencing reduced the inflammatory reaction as attributed by reduced levels of IL-1β, TNF-α and IL-6. Suppressed NLRC4 levels inhibited cell viability and promoted cell apoptosis evidenced by inhibited induction of DC surface markers (CD80, CD86, and MHC II), along with alleviated lung tissue injury. In conclusion, NLRC4 silencing ameliorates lung injury and inflammation induced by septic shock by negatively regulating the NLR pathway.

Abscisic acid ameliorates oxidative stress, inflammation, and apoptosis in thioacetamide-induced hepatic fibrosis by regulating the NF-кB signaling pathway in mice

The purpose of this study was to determine whether abscisic acid (ABA) can protect against liver fibrosis induced by thioacetamide (TAA) in vivo by inhibiting apoptosis and inflammatory responses. To this end, three times per week, mice were injected intraperitoneally with TAA (200 mg/kg) for 8 weeks to induce liver fibrosis. After the fourth week of treatment, histological changes, the serum biochemical index, inflammation, and hepatocyte apoptosis factors (e.g., caspase-3, B-cell lymphoma 2 [Bcl-2], Bcl-2-associated X [Bax]) were detected to clarify its underlying mechanism. The results clearly indicated that ABA improves TAA-induced hepatic injury and collagen accumulation in mice. Otherwise, ABA significantly reduced liver fibrosis by regulating caspase-3 and Bcl-2, α-smooth muscle actin, and collagen I. ABA inhibited the nuclear factor kappa B pathway, significantly alleviating oxidative stress and inflammatory cytokines. Therefore, ABA may be a potential therapeutic agent for preventing liver damage.

MicroRNA-27a inhibits trophoblast cell migration and invasion by targeting SMAD2: Potential role in preeclampsia

Preeclampsia (PE) is a severe idiopathic obstetric complication that occurs worldwide. Insufficient trophoblast invasion is a characteristic of the pathogenesis of PE. MicroRNA-27a (miR-27a) has been reported to be highly expressed in PE placentas. The aim of the present study was to investigate the role and underlying mechanisms of miR-27a in the pathogenesis of PE. The expression level of miR-27a was evaluated in the placenta and serum from patients with PE and healthy pregnant women. Cell Counting Kit-8 and flow cytometry assays were performed to detect human HTR-8/SVneo trophoblast proliferation and apoptosis after miR-27a overexpression or inhibition. In addition, Transwell assays were used to measure cell migration and invasion. A luciferase reporter assay was performed to determine the interaction between miR-27a and SMAD2. The present results suggested that miR-27a expression level was significantly increased in PE placentas and serum. In addition, miR-27a overexpression suppressed cell migratory and invasive abilities, impaired proliferation and promoted apoptosis in human trophoblasts. It was demonstrated that miR-27a may target SMAD and contribute to trophoblast invasion. Collectively, the results of the present study suggested that miR-27a inhibited trophoblast cell migration and invasion by targeting SMAD2, thus presenting a promising therapeutic target for PE.

MHC class I transactivator NLRC5 in host immunity, cancer and beyond

The presentation of antigenic peptides by major histocompatibility complex (MHC) class I and class II molecules is crucial for activation of the adaptive immune system. The nucleotide-binding domain and leucine-rich repeat receptor family members CIITA and NLRC5 function as the major transcriptional activators of MHC class II and class I gene expression, respectively. Since the identification of NLRC5 as the master regulator of MHC class I and class-I-related genes, there have been major advances in understanding the function of NLRC5 in infectious diseases and cancer. Here, we discuss the biological significance and mechanism of NLRC5-dependent MHC class I expression.

Effects of salvianolic acid B on liver fibrosis: A protocol for systematic review and meta analysis

BACKGROUND

Liver fibrosis is a pathological change existing in most chronic liver diseases, which leads to abnormal changes in liver tissue structure and affects the normal physiological function of liver. Without effectively control, liver fibrosis can develop into cirrhosis and increase the risk of liver cancer. Salvianolic acid B (Sal B) is the main active component in the water-soluble extract from Salvia miltiorrhiza, which is a traditional Chinese medicine usually used for treating cardiovascular and liver diseases. It is reported that Sal B shown a good action against liver fibrosis via numerous signaling pathways, which indicate that Sal B is a potential candidate drug for the treatment of liver fibrosis.

METHODS

We searched the related researches from the following electronic databases: PubMed, EMBASE, Web of science, China National Knowledge Infrastructure (CNKI), China Biology Medicine (CBM), Wan fang Database for Chinese Technical Periodicals and VIP Database. All the databases were searched from inception to December 2019. No restriction of language, publication date, or publication status. PICO of this systematic review are shown as flowing: P, preclinical studies which evaluated the effects of Sal B on the animal models of liver fibrosis with controlled studies; I, received Sal B as only treat in any dose; C, received normal saline, distilled water, or no treatment; O, the primary outcome include measure will be the decrease in liver fibrosis score, and the secondary outcomes include the index of liver fibrosis. All the included data will be analyzed with the software of Review Manager 5.2 and STATA 14.2.

DISCUSSION

The purpose of this study is to conduct a systematic review and meta-analysis to assess the effects on anti-liver fibrosis of Sal B, and this will be contribute to drug development and pathological mechanisms of clinical research.

TRIAL REGISTRATION

INPLASY202050101, registered on 28/5/2020.

Current potential therapeutic strategies targeting the TGF-β/Smad signaling pathway to attenuate keloid and hypertrophic scar formation

Aberrant scar formation, which includes keloid and hypertrophic scars, is associated with a pathological disorganized wound healing process with chronic inflammation. The TGF-β/Smad signaling pathway is the most canonical pathway through which the formation of collagen in the fibroblasts and myofibroblasts is regulated. Sustained activation of the TGF-β/Smad signaling pathway results in the long-term overactivation of fibroblasts and myofibroblasts, which is necessary for the excessive collagen formation in aberrant scars. There are two categories of therapeutic strategies that aim to target the TGF-β/Smad signaling pathway in fibroblasts and myofibroblasts to interfere with their cellular functions and reduce cell proliferation. The first therapeutic strategy includes medications, and the second strategy is composed of genetic and cellular therapeutics. Therefore, the focus of this review is to critically evaluate these two main therapeutic strategies that target the TGF-β/Smad pathway to attenuate abnormal skin scar formation.

Odontogenic infection by Porphyromonas gingivalis exacerbates fibrosis in NASH via hepatic stellate cell activation

Odontogenic infection of Porphyromonas gingivalis (P.g.), a major periodontal pathogen, exacerbates pathological progression of non-alcoholic steatohepatitis (NASH). In this study, we aimed to clarify the detailed mechanism in which P.g. induced hepatic stellate cells (HSCs; key effector cells in liver fibrosis) activation. In the liver of high fat diet-induced NASH mouse model with P.g. odontogenic infection, immunolocalization of P.g. was detected. The number of hepatic crown-like structure, which was macrophage aggregation and related to liver fibrosis, was drastically increased and fibrosis area was also increased through upregulating immunoexpression of Phosphorylated Smad2 (key signaling molecule of TGF-β1) and Galectin-3. P.g.-secreted trypsin-like enzyme [gingipain; an activator of protease-activated receptor 2 (PAR2)] stimulated HSC proliferation and differentiation through Smad and ERK signaling induced by TGF-β1 produced from HSCs with P.g.-infection. Further, Galectin-3 produced from HSCs with P.g. infection and P.g.-derived LPS/lipoprotein stimulation stabilized TGFβ-receptor II resulting in increasing sensitivity for TGF-β1, finally leading to HSC differentiation via activating Smad and ERK signaling. In addition to them, hepatocytes (main component cells of liver) contributed to HSC activation through TGF-β1 and Galectin-3 production in paracrine manner. Collectively, P.g.-odontogenic infection exacerbates fibrosis of NASH by HSC activation through TGF-β1 and Gal-3 production from HSCs and hepatocytes.

siRNA- and miRNA-based therapeutics for liver fibrosis

Liver fibrosis is a wound-healing process induced by chronic liver injuries, such as nonalcoholic steatohepatitis, hepatitis, alcohol abuse, and metal poisoning. The accumulation of excessive extracellular matrix (ECM) in the liver is a key characteristic of liver fibrosis. Activated hepatic stellate cells (HSCs) are the major producers of ECM and therefore play irreplaceably important roles during the progression of liver fibrosis. Liver fibrogenesis is highly correlated with the activation of HSCs, which is regulated by numerous profibrotic cytokines. Using RNA interference to downregulate these cytokines in activated HSCs is a promising strategy to reverse liver fibrosis. Meanwhile, microRNAs (miRNAs) have also been exploited for the treatment of liver fibrosis. This review focuses on the current siRNA- and miRNA-based liver fibrosis treatment strategies by targeting activated HSCs in the liver.

Emerging Roles for NLRC5 in Immune Diseases

Innate immunity activates the corresponding immune response relying on multiple pattern recognition receptors (PRRs) that includes pattern recognition receptors (PRRs), like NOD-like receptors (NLRs), RIG-I-like receptors (RLRs), and C-type lectin receptors (CLRs), which could accurately recognize invasive pathogens. In particular, NLRs belong to a large protein family of pattern recognition receptors in the cytoplasm, where they are highly correlated with activation of inflammatory response system followed by rapid clearance of invasive pathogens. Among the NLRs family, NLRC5, also known as NOD4 or NOD27, accounts for a large proportion and involves in immune responses far and wide. Notably, in the above response case of inflammation, the expression of NLRC5 remarkably increased in immune cells and immune-related tissues. However, the evidence for higher expression of NLRC5 in immune disease still remains controversial. It is noted that the growing evidence further accounts for the participation of NLRC5 in the innate immune response and inflammatory diseases. Moreover, NLRC5 has also been confirmed to exert a critical role in the control of regulatory diverse signaling pathways. Together with its broad participation in the occurrence and development of immune diseases, NLRC5 can be consequently treated as a potential therapeutic target. Nevertheless, the paucity of absolute understanding of intrinsic characteristics and underlying mechanisms of NLRC5 still make it hard to develop targeting drugs. Therefore, current summary about NLRC5 information is indispensable. Herein, current knowledge of NLRC5 is summarized, and research advances in terms of NLRC5 in characteristics, biological function, and regulatory mechanisms are reviewed.

The deficiency of miR-214-3p exacerbates cardiac fibrosis via miR-214-3p/NLRC5 axis

Cardiac fibrosis is a common pathological feature of many cardiovascular diseases. The regulatory mechanisms of miRNAs in cardiac fibrosis are still unknown. Previous studies on miR-214-3p in cardiac fibroblasts reached contradictory conclusions. Thus the role of miR-214-3p in cardiac fibrosis deserves further exploration. Using a combination of in vitro and in vivo studies, we identified miR-214-3p as an important regulator of cardiac fibrosis, and the proliferation and activation of cardiac fibroblasts. We demonstrated that the expression of miR-214-3p is down-regulated in TGF-β1-treated myofibroblasts and transverse aortic constriction (TAC)-induced murine model. Additionally, miR-214-3pflox/flox/FSP1-cre mice and miR-214-3pwt/wt/FSP1-cre mice were subjected to TAC operation or sham operation, and the conditional knockout of miR-214-3p in cardiac fibroblasts aggravates TAC-induced cardiac fibrosis. In vitro, our results indicate that miR-214-3p is an important repressor for fibroblasts proliferation and fibroblast-to-myofibroblast transition by functionally targeting NOD-like receptor family CARD domain containing 5 (NLRC5). In conclusion, our findings show that the deficiency of miR-214-3p exacerbates cardiac fibrosis and reveal a novel miR-214-3p/NLRC5 axis in the regulation of cardiac fibrosis.

Research progress on the anti-hepatic fibrosis action and mechanism of natural products

Hepatic fibrosis is the most common pathological feature of most chronic liver diseases, and its continuous deterioration gradually develops into liver cirrhosis and eventually leads to liver cancer. At present, there are many kinds of drugs used to treat liver fibrosis. However, Western drugs tend to only target single genes/proteins and induce many adverse reactions. Most of the mechanisms and active ingredients of traditional Chinese medicine (TCM) are not clear, and there is a lack of unified diagnosis and treatment standards. Natural products, which are characterized by structural diversity, low toxicity, and origination from a wide range of sources, have unique advantages and great potential in anti-liver fibrosis. This article summarizes the work done over the previous decade, on the active ingredients in natural products that are reported to have anti-hepatic fibrosis effects. The effective anti-hepatic fibrosis ingredients identified can be generally divided into flavonoids, saponins, polysaccharides and alkaloids. Mechanisms of anti-liver fibrosis include inhibition of liver inflammation, anti-lipid peroxidation injury, inhibition of the activation and proliferation of hepatic stellate cells (HSCs), modulation of the synthesis and secretion of pro-fibrosis factors, and regulation of the synthesis and degradation of the extracellular matrix (ECM). This review provides suggestions for the development of anti-hepatic fibrosis drugs.

The Long Non-coding RNA MEG3/miR-let-7c-5p Axis Regulates Ethanol-Induced Hepatic Steatosis and Apoptosis by Targeting NLRC5

Ethanol (EtOH)-induced hepatic injury, characterized by hepatic steatosis with apoptosis, causes heavy health burden personally and socially. Long non-coding RNAs (lncRNAs) have been implicated in liver diseases. However, the role of lncRNA maternally expressed gene 3 (MEG3) in EtOH-induced hepatic injury remains unknown. The aim of present study was to assess the function of MEG3 and its functional interaction with miR-let-7c-5p in EtOH-induced hepatic injury. Here, we observed that MEG3 and NLRC5 expression was increased and miR-let-7c-5p expression decreased in EtOH-fed mice and EtOH-induced AML-12 cells. Knockdown of MEG3 contributed to attenuation of EtOH-induced steatosis and apoptosis in AML-12 cells. Also, expression level of MEG3 negatively correlated with miR-let-7c-5p expression and positively correlated with NLRC5 expression. In contrary to MEG3, miR-let-7c-5p overexpression attenuated EtOH-induced steatosis and apoptosis, as well as suppressed EtOH-induced increase in NLRC5 expression. By luciferase reporter assay, we concluded that miR-let-7c-5p directly binds to NLRC5 3′-UTR, thereby negatively regulates NLRC5 expression. Our data suggested that lncRNA MEG3 functions as a competing endogenous RNA for miR-let-7c-5p to regulate NLRC5 expression in EtOH-induced hepatic injury.

Knockdown of NLRC5 inhibits renal fibroblast activation via modulating TGF-β1/Smad signaling pathway

NLRC5, the largest member of the Nucleotide-binding domain and leucine-rich repeat (NLR) protein family, is recently proven to be a critical modulator in fibrogenesis. However, the role of NLRC5 in renal fibrosis remains unknown. In the present study, we investigated the effects of NLRC5 on transforming growth factor β1 (TGF-β1)-stimulated rat renal fibroblasts in vitro. Our results showed that the expression of NLRC5 was also obviously upregulated in renal fibrosis tissues and TGF-β1-treated NRK-49F cells. Knockdown of NLRC5 inhibited the proliferation of NRK-49F cells induced by TGF-β1, as well as suppressed the accumulation of extracellular matrix (ECM) in NRK-49F cells induced by TGF-β1. Furthermore, knockdown of NLRC5 inhibited the expression of phosphorylated Smad3 in TGF-β1-treated NRK-49F cells. In conclusion, our results show that knockdown of NLRC5 inhibits renal fibroblast activation via modulating TGF-β1/Smad signaling pathway. Therefore, NLRC5 may act as a key mediator in renal fibroblast activation and fibrogenesis.

Transforming growth factor β1 promotes invasion of human JEG-3 trophoblast cells via TGF-β/Smad3 signaling pathway

Transforming growth factor (TGF)-β1 is involved invasion of human trophoblasts. However, the underlying mechanisms remain unclear. In this study, we performed Transwell assay and found that TGF-β1 promoted the invasion of trophoblast cell line JEG-3. Treatment with TGF-β1 up-regulated the expression of receptor-regulated Smad transcription factors Smad2 and Smad3, and two invasive-associated genes, namely, matrix metallopeptidase (MMP)-9 and MMP-2, in JEG-3 cells. Over-expressing activin receptor-like kinase (ALK) 5, the TGF-β type I receptor (TβRI) enhanced the up-regulation of Smad2, Smad3, MMP-9, and MMP-2 induced by TGF-β1, whereas application of TβRI inhibitor SB431542 diminished the stimulatory effects of TGF-β1 on these genes. Furthermore, transfection of Smad3 and ALK-5 seperately or in combination into JEG-3 cells before TGF-β1 treatment significantly increased the expression of MMP-9 and MMP-2. By contrast, silencing Smad3 and Smad2 by siRNAs significantly decreased the expression of MMP-9 and MMP-2, with Smad3 silence having a more potent inhibitory effect. Inhibiting TβRI with SB431542 or knockdown of Smad3, but not Smad2, abolished the stimulatory effect of TGF-β1 on the invasion of JEG-3 cells. Taken together, the results indicate that TGF-β1 activates the Smads signaling pathway in JEG-3 trophoblast cells and Smad3 play a key role in TGF-β1-induced invasion of JEG-3 and up-regulation of MMP-9 and MMP-2 expression.

NLRC5 deficiency ameliorates diabetic nephropathy through alleviating inflammation

NOD-like receptor family caspase recruitment domain family domain containing 5 (NLRC5) has important roles in inflammation and innate immunity. NLRC5 was highly expressed in kidney from streptozotocin-induced diabetic mice, db/ db mice and patients with diabetes. Based on that evidence, the present study was designed to explore the roles of NLRC5 in the progression of diabetic nephropathy (DN). We examined kidney injury, including inflammation and fibrosis in Nlrc5 gene knockout ( Nlrc5^-/-) and wild-type (WT) diabetic mice. We found that Nlrc5^-/- mice developed less-severe diabetic kidney injury compared with WT mice, exhibiting lower albuminuria, less fibronectin and collagen IV expression, and reduced macrophage infiltration but greater levels of podocin and nephrin in the diabetic kidney. The underlying mechanisms were further investigated in vitro with peritoneal macrophages and mesangial cells treated with high glucose. Reduced proinflammatory effect was observed in peritoneal macrophages from Nlrc5^-/- mice, associated with NF-κB pathway suppression. Knocking down of NLRC5 in mesangial cells in high-glucose conditions was also associated with reduced NF-κB and TGF-β/Smad signaling. Taken together, NLRC5 promotes inflammation and fibrosis during DN progression partly through the effects on NF-κB and TGF-β/Smad pathways. NLRC5 may, therefore, be a promising therapeutic target for DN treatment.-Luan, P., Zhuang, J., Zou, J., Li, H., Shuai, P., Xu, X., Zhao, Y., Kou, W., Ji, S., Peng, A., Xu, Y., Su, Q., Jian, W., Peng, W. NLRC5 deficiency ameliorates diabetic nephropathy through alleviating inflammation.

Chlorogenic Acid Inhibits Liver Fibrosis by Blocking the miR-21-Regulated TGF-β1/Smad7 Signaling Pathway in Vitro and in Vivo

Aims: Chlorogenic acid (CGA) is a phenolic acid that has a wide range of pharmacological effects. However, the protective effects and mechanisms of CGA on liver fibrosis are not clear. This study explored the effects of CGA on miR-21-regulated TGF-β1/Smad7 liver fibrosis in the hepatic stellate LX2 cell line and in CCl4-induced liver fibrosis in Sprague-Dawley rats.

Methods: The mRNA expression of miR-21, Smad7, connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), tissue inhibitor of metalloproteinase 1 (TIMP-1), matrix metalloproteinase-9 (MMP-9), and transforming growth factor-β1 (TGF-β1) and the protein levels of Smad2, p-Smad2, Smad3, p-Smad3, Smad2/3, p-Smad2/3, Smad7, CTGF, α-SMA, TIMP-1, MMP-9 and TGF-β1 were assayed in LX2 cells and liver tissue. The effects of CGA after miR-21 knockdown or overexpression were analyzed in LX2 cells. The liver tissue and serum were collected for histopathological examination, immunohistochemistry (IHC) and ELISA.

Results: The mRNA expression of miR-21, CTGF, α-SMA, TIMP-1, and TGF-β1 and the protein expression of p-Smad2, p-Smad3, p-Smad2/3, CTGF, α-SMA, TIMP-1, and TGF-β1 were inhibited by CGA both in vitro and in vivo. Meanwhile, CGA elevated the mRNA and protein expression of Smad7 and MMP-9. After miR-21 knockdown and overexpression, the downstream molecules also changed accordingly. CGA also lessened the degree of liver fibrosis in the pathological manifestation and reduced α-SMA and collagen I expression in liver tissue and TGF-β1 in serum. Conclusion: CGA might relieve liver fibrosis through the miR-21-regulated TGF-β1/Smad7 signaling pathway, which suggests that CGA might be a new anti-fibrosis agent that improves liver fibrosis.

Nanoparticles for the treatment of liver fibrosis

Chronic liver diseases represent a global health problem due to their high prevalence worldwide and the limited available curative treatment options. They can result from various causes, both infectious and noninfectious diseases. The application of nanoparticle (NP) systems has emerged as a rapidly evolving area of interest for the safe delivery of various drugs and nucleic acids for chronic liver diseases. This review presents the pathogenesis, diagnosis and the emerging nanoparticulate systems used in the treatment of chronic liver diseases caused by liver fibrosis. Activated hepatic stellate cell (HSC) is considered to be the main mechanism for liver fibrosis. Ultrasonography and magnetic resonance imaging techniques are widely used noninvasive diagnostic methods for hepatic fibrosis. A variety of nanoparticulate systems are mainly focused on targeting HSC in the treatment of hepatic fibrosis. As early liver fibrosis is reversible by current NP therapy, it is being studied in preclinical as well as clinical trials. Among various nanoparticulate systems, inorganic NPs, liposomes and nanomicelles have been widely studied due to their distinct properties to deliver drugs as well as other therapeutic moieties. Liposomal NPs in clinical trials is considered to be a milestone in the treatment of hepatic fibrosis. Currently, NP therapy for liver fibrosis is updating fast, and hopefully, it can be the future remedy for liver fibrosis.

NLRC5 promotes cell proliferation via regulating the NF-κB signaling pathway in Rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease and the pathogenesis remains unclear. Previous studies suggested that fibroblast-like synoviocytes (FLSs) play an important role in RA pathogenesis, including the injury of cartilage, the hyperplasia of the synovium and the release of inflammatory cytokines. We used complete Freund's adjuvant (CFA) induced rats as animal models for studying the RA pathogenesis. NLRC5 as the largest member of the NLR family has been reported to play a critical role in regulating immune responses. Increasing evidence suggests that NLRC5 is an pivotal negative modulator of inflammatory pathways. We investigated the mechanisms and signaling pathways of NLRC5 in RA progression. Significantly increased expression of NLRC5 was found in AA rats synovial tissues and cells. And high expression of inflammatory cytokine and cell proliferation of FLSs accompanied with NLRC5 overexpression, but inhibited in cells with NLRC5 silencing treatment. Interestingly, we found that overexpression of NLRC5 also coordinated the activation of NF-κB signaling pathway. These results suggested that NLRC5 promotes RA progression via the NF-κB signaling pathway potentially.

Casticin attenuates liver fibrosis and hepatic stellate cell activation by blocking TGF-β/Smad signaling pathway

Although many advances have been made in understanding the pathogenesis of liver fibrosis, few options are available for treatment. Casticin, one of the major flavonoids in Fructus Viticis extracts, has shown hepatoprotective potential, but its effects on liver fibrosis are not clear. In this study, we investigated the antifibrotic activity of casticin and its underlying mechanism in vivo and in vitro. Male mice were injected intraperitoneally with carbon tetrachloride (CCl4) or underwent bile duct ligation (BDL) to induce liver fibrosis, followed by treatment with casticin or vehicle. In addition, transforming growth factor-β1(TGF-β1)-activated LX-2 cells were used. In vivo experiments showed that treatment with casticin alone had no toxic effect while significantly attenuating CCl4-or BDL-induced liver fibrosis, as indicated by reductions in the density of fibrosis, hydroxyproline content, expression of α-SMA and collagen α1(I) mRNA. Moreover, casticin inhibited LX2 proliferation, induced apoptosis in a time- and dose-dependent manner in vitro. The underlying molecular mechanisms for the effect of casticin involved inhibition of hepatic stellate cell (HSC) activation and reduced the expression of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinases (TIMP)-1 and TIMP-2 resulting from blocking TGF-β1/Smad signaling, as well as increased the apoptosis of HSCs. The results suggest that casticin has potential benefits in the attenuation and treatment of liver fibrosis.

NLRC5 silencing ameliorates cardiac fibrosis by inhibiting the TGF‑β1/Smad3 signaling pathway

The proliferation of cardiac fibroblasts (CFs) and excessive deposition of extracellular matrix are the predominant pathological characteristics of cardiac fibrosis. As the largest member of the nucleotide‑binding domain and leucine‑rich repeat (NLR) family, NLRC5 has been shown to be pivotal in the development of hepatic fibrosis. However, whether NLRC5 is involved in the pathogenesis of cardiac fibrosis remains to be elucidated. The present study aimed to investigate the role of NLRC5 and its mechanisms in regulating cardiac fibrosis. CFs were stimulated with transforming growth factor (TGF)‑β1 for various times and the mRNA and protein expression of NLRC5 was assessed using reverse transcription‑quantitative polymerase chain reaction and western blot analysis, respectively. In addition, CFs were transfected with small interfering (si)RNA targeting NLRC5 or scramble siRNA for 24 h and then stimulated with TGF‑β1 for 24 h. Subsequently, cell proliferation was measured using an MTT assay, whereas cell migration was evaluated using a Transwell migration assay. The protein expression levels of α‑smooth muscle actin, collagen I, connective tissue growth factor, phosphorylated‑Smad3 and Smad3 were measured using western blot analysis. The results demonstrated that NLRC5 was upregulated in TGF‑β1‑induced CFs. The knockdown of NLRC5 significantly inhibited cell proliferation and migration, and suppressed myofibroblast differentiation and the expression of pro‑fibrotic molecules in TGF‑β1‑treated CFs. Furthermore, the knockdown of NLRC5 attenuated TGF‑β1‑induced phosphorylation of small mothers against decapentaplegic (Smad)3 in the CFs. The results of the present study indicated that NLRC5 acted as a key regulator of pathological cardiac fibrosis, and NLRC5 silencing ameliorated cardiac fibrosis by inhibiting the TGF‑β1/Smad3 signaling pathway. These results suggested that NLRC5 may be a novel target for attenuating cardiac fibrosis.

Protective Effects of Amarogentin against Carbon Tetrachloride-Induced Liver Fibrosis in Mice

Amarogentin, a secoiridoid glycoside that is mainly extracted from Swertia and Gentiana roots, has been suggested to exhibit many biological effects, including anti-oxidative, anti-tumour, and anti-diabetic activities. The present study was designed to evaluate the protective effects of amarogentin on carbon tetrachloride-induced liver fibrosis in vivo and the underlying mechanism. Fibrosis was induced by subcutaneous injections of 6 mL/kg of 20% carbon tetrachloride (dissolved in olive oil) twice per week for seven weeks. Mice were orally treated with 25, 50, and 100 mg/kg amarogentin and with colchicine as a positive control. Biochemical assays and histopathological investigations showed that amarogentin delayed the formation of liver fibrosis; decreased alanine aminotransferase, aspartate aminotransferase, malondialdehyde and hydroxyproline levels; and increased albumin, cyclic guanosine monophosphate, glutathione peroxidase, and superoxide dismutase levels. Moreover, amarogentin exhibited downregulation of α-smooth muscle actin and transforming growth factor-β₁ levels in immunohistochemical and Western blot analyses. The levels of phosphorylated extracellular regulated protein kinases, c-Jun N-terminal kinase, and p38 were also significantly reduced in all amarogentin-treated groups in a dose-dependent manner. These findings demonstrated that amarogentin exerted significant hepatoprotective effects against carbon tetrachloride-induced liver fibrosis in mice and suggested that the effect of amarogentin against liver fibrosis may be by anti-oxidative properties and suppressing the mitogen-activated protein kinase signalling pathway.

Ionone Derivatives from the Mycelium of Phellinus linteus and the Inhibitory Effect on Activated Rat Hepatic Stellate Cells

Three new γ-ionylideneacetic acid derivatives, phellinulins A-C (1-3), were characterized from the mycelium extract of Phellinus linteus. The chemical structures were established based on the spectroscopic analysis. In addition, phellinulin A (1) was subjected to the examination of effects on activated rat hepatic stellate cells and exhibited significant inhibition of hepatic fibrosis.