Identification of Cysteine-Rich Angiogenic Inducer 61 as a Potential Antifibrotic and Proangiogenic Mediator in Scleroderma

Noval advance of histone modification in inflammatory skin diseases and related treatment methods

Inflammatory skin diseases are a group of diseases caused by the disruption of skin tissue due to immune system disorders. Histone modification plays a pivotal role in the pathogenesis and treatment of chronic inflammatory skin diseases, encompassing a wide range of conditions, including psoriasis, atopic dermatitis, lupus, systemic sclerosis, contact dermatitis, lichen planus, and alopecia areata. Analyzing histone modification as a significant epigenetic regulatory approach holds great promise for advancing our understanding and managing these complex disorders. Additionally, therapeutic interventions targeting histone modifications have emerged as promising strategies for effectively managing inflammatory skin disorders. This comprehensive review provides an overview of the diverse types of histone modification. We discuss the intricate association between histone modification and prevalent chronic inflammatory skin diseases. We also review current and potential therapeutic approaches that revolve around modulating histone modifications. Finally, we investigated the prospects of research on histone modifications in the context of chronic inflammatory skin diseases, paving the way for innovative therapeutic interventions and improved patient outcomes.

Induction of Sestrin2 by pterostilbene suppresses ethanol-triggered hepatocyte senescence by degrading CCN1 via p62-dependent selective autophagy

Hepatocyte senescence is a key event participating in the progression of alcoholic liver disease. Autophagy is a critical biological process that controls cell fates by affecting cell behaviors like senescence. Pterostilbene is a natural compound with hepatoprotective potential; however, its implication for alcoholic liver disease was not understood. This study was aimed to investigate the therapeutic effect of pterostilbene on alcoholic liver disease and elucidate the potential mechanism. Our results showed that pterostilbene alleviated ethanol-triggered hepatocyte damage and senescence. Intriguingly, pterostilbene decreased the protein abundance of cellular communication network factor 1 (CCN1) in ethanol-exposed hepatocytes, which was essential for pterostilbene to execute its anti-senescent function. In vivo studies verified the anti-senescent effect of pterostilbene on hepatocytes of alcohol-intoxicated mice. Pterostilbene also relieved senescence-associated secretory phenotype (SASP), redox imbalance, and steatosis by suppressing hepatic CCN1 expression. Mechanistically, pterostilbene-forced CCN1 reduction was dependent on posttranscriptional regulation via autophagy machinery but not transcriptional regulation. To be specific, pterostilbene restored autophagic flux in damaged hepatocytes and activated p62-mediated selective autophagy to recognize and lead CCN1 to autolysosomes for degradation. The protein abundance of Sestrin2 (SESN2), a core upstream modulator of autophagy pathway, was decreased in ethanol-administrated hepatocytes but rescued by co-treatment with pterostilbene. Induction of SESN2 protein by pterostilbene rescued ethanol-triggered autophagic dysfunction in hepatocytes, which then reduced senescence-associated markers, postponed hepatocyte senescence, and relieved alcohol-caused liver injury and inflammation. In conclusion, this work discovered a novel compound pterostilbene with therapeutic implications for alcoholic liver disease and uncover its underlying mechanism.

SARA suppresses myofibroblast precursor transdifferentiation in fibrogenesis in a mouse model of scleroderma

We previously reported that Smad anchor for receptor activation (SARA) plays a critical role in maintaining epithelial cell phenotype. Here, we show that SARA suppressed myofibroblast precursor transdifferentiation in a mouse model of scleroderma. Mice overexpressing SARA specifically in PDGFR-β+ pericytes and pan-leukocytes (SARATg) developed significantly less skin fibrosis in response to bleomycin injection compared with wild-type littermates (SARAWT). Single-cell RNA-Seq analysis of skin PDGFR-β+ cells implicated pericyte subsets assuming myofibroblast characteristics under fibrotic stimuli, and SARA overexpression blocked the transition. In addition, a cluster that expresses molecules associated with Th2 cells and macrophage activation was enriched in SARAWT mice, but not in SARATg mice, after bleomycin treatment. Th2-specific Il-31 expression was increased in skin of the bleomycin-treated SARAWT mice and patients with scleroderma (or systemic sclerosis, SSc). Receptor-ligand analyses indicated that lymphocytes mediated pericyte transdifferentiation in SARAWT mice, while with SARA overexpression the myofibroblast activity of pericytes was suppressed. Together, these data suggest a potentially novel crosstalk between myofibroblast precursors and immune cells in the pathogenesis of SSc, in which SARA plays a critical role.

HDAC5 inactivates CYR61-regulated CD31/mTOR axis to prevent the occurrence of preeclampsia

Our study was to pinpoint the significance of histone deacetylase 5 (HDAC5) affecting the pathogenesis of preeclampsia (PE) via CD31/mammalian target of rapamycin (mTOR) axis by regulating cysteine-rich angiogenic inducer 61 (CYR61). Expression of HDAC5, CYR61, and CD31/mTOR in placental tissues of patients with PE and trophoblast cells HTR-8/SVneo cells was determined first followed by their interaction analysis. Following different transfection, the significance of HDAC5 in cell functions was assayed in relation to CYR61 and CD31/mTOR. An in vivo PE mouse model was constructed for further validation. The clinical tissue and in vitro cell experimentations discovered that HDAC5 was downregulated in placental tissues of PE patients and trophoblast cells, while CYR61, CD31, mTOR, and p-mTOR displayed upregulation. After overexpression of HDAC5, trophoblast cell functions were enhanced. HDAC5 reduced the acetylation enrichment of H3K27 to inhibit the expression of CYR61. Furthermore, CYR61 promoted the activation of CD31/mTOR axis, thereby inhibiting HTR-8/SVneo cell functions. The in vivo rat model confirmed the above alterations. Taken together, HDAC5 contributes to downregulation of CYR61 through histone deacetylation, inactivating CD31/mTOR axis, which prevents the occurrence and development of PE.

Natural Bioactive Compounds Targeting Histone Deacetylases in Human Cancers: Recent Updates

Cancer is a complex pathology that causes a large number of deaths worldwide. Several risk factors are involved in tumor transformation, including epigenetic factors. These factors are a set of changes that do not affect the DNA sequence, while modifying the gene’s expression. Histone modification is an essential mark in maintaining cellular memory and, therefore, loss of this mark can lead to tumor transformation. As these epigenetic changes are reversible, the use of molecules that can restore the functions of the enzymes responsible for the changes is therapeutically necessary. Natural molecules, mainly those isolated from medicinal plants, have demonstrated significant inhibitory properties against enzymes related to histone modifications, particularly histone deacetylases (HDACs). Flavonoids, terpenoids, phenolic acids, and alkaloids exert significant inhibitory effects against HDAC and exhibit promising epi-drug properties. This suggests that epi-drugs against HDAC could prevent and treat various human cancers. Accordingly, the present study aimed to evaluate the pharmacodynamic action of different natural compounds extracted from medicinal plants against the enzymatic activity of HDAC.

Functional Characterization of Glycoprotein Nonmetastatic Melanoma Protein B in Scleroderma Fibrosis

Glycoprotein nonmetastatic melanoma protein B (GPNMB) is involved in various cell functions such as cell adhesion, migration, proliferation, and differentiation. In this study, we set forth to determine the role of GPNMB in systemic sclerosis (SSc) fibroblasts. Dermal fibroblasts were isolated from skin biopsies from healthy subjects and patients with diffuse cutaneous (dc)SSc. GPNMB was upregulated in dcSSc fibroblasts compared to normal fibroblasts, and correlated negatively with the modified Rodnan skin score. In addition, dcSSc fibroblasts secreted higher levels of soluble (s)GPNMB (147.4 ± 50.2 pg/ml vs. 84.8 ± 14.8 pg/ml, p<0.05), partly due to increased ADAM10. sGPNMB downregulated profibrotic genes in dcSSc fibroblasts and inhibited cell proliferation and gel contraction. The anti-fibrotic effect of sGPNMB was at least in part mediated through CD44, which is regulated by histone acetylation. TGFβ downregulated GPNMB and decreased the release of its soluble form in normal fibroblasts. In dcSSc fibroblasts, GPNMB is upregulated by its own soluble form. Our data demonstrate an anti-fibrotic role of sGPNMB in SSc and established a role for the ADAM10-sGPNMB-CD44 axis in dermal fibroblasts. Upregulating GPNMB expression might provide a novel therapeutic approach in SSc.

Inhibition of histone readers bromodomain extra-terminal proteins alleviates skin fibrosis in experimental models of scleroderma

Binding of the bromodomain and extraterminal domain proteins (BETs) to acetylated histone residues is critical for gene transcription. We sought to determine the antifibrotic efficacy and potential mechanisms of BET inhibition in systemic sclerosis (SSc). Blockade of BETs was done using a pan-BET inhibitor, JQ1; BRD2 inhibitor, BIC1; or BRD4 inhibitors AZD5153 or ARV825. BET inhibition, specifically BRD4 blockade, showed antifibrotic effects in an animal model of SSc and in patient-derived diffuse cutaneous SSc (dcSSc) fibroblasts. Transcriptome analysis of JQ1-treated dcSSc fibroblasts revealed differentially expressed genes related to extracellular matrix, cell cycle, and calcium (Ca²⁺) signaling. The antifibrotic effect of BRD4 inhibition was mediated at least in part by downregulation of Ca²⁺/calmodulin–dependent protein kinase II α and reduction of intracellular Ca²⁺ concentrations. On the basis of these results, we propose targeting Ca²⁺ pathways or BRD4 as potentially novel therapeutic approaches for progressive tissue fibrosis.

Proteomic characteristics of PM2.5 -induced differentially expressed proteins in human renal tubular epithelial cells

Human renal epithelial (HK-2) cells were treated with PM_2.5 (50 μg/mL) from Shenzhen and Taiyuan, proteomics and bioinformatics were used to screen the differentially expressed proteins (DEPs). A total of 577 DEPs were screened after HK-2 cells exposed to Shenzhen PM_2.5, of which 426 were up-regulated and 151 were down-regulated. A total of 1250 DEPs were screened in HK-2 cells after exposure to Taiyuan PM_2.5, of which 488 were up-regulated and 185 were down-regulated. The top 10 proteins with the highest number of nodes were screened using the interaction network map of DEPs. HK-2 cells exposed to Shenzhen PM_2.5 contained CYR61, CTGF, and THBS1 proteins, while HK-2 cells exposed to Taiyuan PM_2.5 contained ALB, FN1, and CYR61 proteins. Additionally, PM_2.5 components were detected, PM_2.5 samples from Shenzhen and Taiyuan induced obvious changes in DEPs expression, the difference in DEPs between the two cities was probably associated with the different PM_2.5 components.

Characterization of Histone Deacetylase Mechanisms in Cancer Development

Over decades of studies, accumulating evidence has suggested that epigenetic dysregulation is a hallmark of tumours. Post-translational modifications of histones are involved in tumour pathogenesis and development mainly by influencing a broad range of physiological processes. Histone deacetylases (HDACs) and histone acetyltransferases (HATs) are pivotal epigenetic modulators that regulate dynamic processes in the acetylation of histones at lysine residues, thereby influencing transcription of oncogenes and tumour suppressor genes. Moreover, HDACs mediate the deacetylation process of many nonhistone proteins and thus orchestrate a host of pathological processes, such as tumour pathogenesis. In this review, we elucidate the functions of HDACs in cancer.

Expression of Cyr61 is associated with clinical course in patients with Crohn's disease

Backgrounds

Cysteine-rich angiogenic inducer 61 (Cyr61) is emerging as an important regulator of tissue homeostasis and wound repair. We aim to explore the colonic mucosal expression of Cyr61 and analyze the association between Cyr61 expression and clinical course in patients with Crohn’s disease (CD).

Methods

Endoscopic samples were identified from 83 CD patients with and 372 controls by searching pathological reports. Among them, age- and sex- matched 43 of each group by a propensity score were selected to compare Cyr61 expression by immunohistochemistry (IHC). IHC scores for Cyr61 expression of CD patients were divided into tertiles to evaluate the association with clinical course. We also measured the level of mRNA for Cyr 61 and proinflammatory genes in inflamed and noninflamed colonic mucosal lesions from CD patients.

Results

The mean IHC scores for Cyr61 expression was higher in CD patients (86.5) than in controls (46.1, P < 0.001). In CD patients, the mean IHC scores for Cyr61 expression (68.3) was lower in patients with clinical recurrence than in patients without recurrence (92.2, P = 0.01). Cyr61 mRNA levels in inflamed mucosa were twofold higher than those in non-inflamed lesion (P > 0.05) and the mRNA levels of IL-6 and TLR-4 in inflamed mucosa were significantly higher than those in non-inflamed mucosa in CD patients (all P < 0.05). When CD patients were stratified into tertile groups according to IHC scores for Cyr61 expression, clinical recurrence rates tended to be lower in patients with high Cyr61 expression (P for trend = 0.02). Compared with tertile 1 of Cyr61 expression, tertile 3 of Cyr 61 expression was associated with reduced risk of clinical recurrence (OR 0.43, 95% CI 0.20–0.92) after adjustment for age, sex and CD activity index at the time of colonoscopy in CD patients (P = 0.03).

Conclusions

Cyr61 mucosal expression in CD patients was inversely associated with clinical course. Future study need to be considered to evaluate whether Cyr 61 may play a role in activating inflammatory responses and contributing to wound healing and tissue repair in patients with CD.

Inhibition of cellular communication network factor 1 (CCN1)-driven senescence slows down cartilage inflammaging and osteoarthritis

OBJECTIVE

To explore the role of cellular communication network factor 1 (CCN1) in cartilage inflammaging and osteoarthritis (OA) pathogenesis in the isolated primary human chondrocytes in vitro, cartilage explants ex vivo, and a pre-clinical mice model.

METHODS

Recombinant human CCN1 stimulation and small interfering RNA inhibition were conducted in human chondrocytes. The RNA was extracted to quantify catabolic targets and pro-inflammatory genes and the proteins were probed with specific antibodies. IL-1β and IL-6 were monitored by ELISA. IHC was performed to evaluate important hypertrophic hallmarks and catabolic markers. The effects of Tanshinone IIA on chondrocytes were investigated in both time-dependent and dose-dependent processes. Cartilage explants were cultured in growth medium and further treated with Tanshinone IIA. The intra-articular injection was performed in 13 months old C57BL/6J mice. Safranin O and fast green staining were performed to evaluate the histological change of cartilage followed by a semi-quantitative analysis using the OARSI scoring system.

RESULTS

RNA and protein levels of CCN1 increased in an age-dependent manner compared to young donors. Increased CCN1 expression was also found in the damaged area compared to the non-lesion area which correlated with the advanced pathological change in human OA. The overexpression of CCN1 promoted chondrocytes senescence, while the down-regulation of CCN1 by small interfering RNA reduced CCN1 production and limited inflammation secretion suggesting that CCN1 was a possible novel target to intervene OA. Inhibition of CCN1 by using Tanshinone IIA could reduce SASP components in a dose- and time-dependent manner. Additionally, our data showed that Tanshinone IIA was able to preserve articular cartilage integrity, suppress CCN1 production, and inhibit SASP factors in human cartilage explants and in aged mice model.

CONCLUSION

This study showed that CCN1 signaling aggravated cartilage inflammaing and matrix degradation. Collectively, our findings showed new insight into repurposing Tanshinone IIA for slowing down OA advancement in human and mice by inhibiting the CCN1 axis.

Emerging Roles of Matricellular Proteins in Systemic Sclerosis

Systemic sclerosis is a rare chronic heterogenous disease that involves inflammation and vasculopathy, and converges in end-stage development of multisystem tissue fibrosis. The loss of tight spatial distribution and temporal expression of proteins in the extracellular matrix (ECM) leads to progressive organ stiffening, which is a hallmark of fibrotic disease. A group of nonstructural matrix proteins, known as matricellular proteins (MCPs) are implicated in dysregulated processes that drive fibrosis such as ECM remodeling and various cellular behaviors. Accordingly, MCPs have been described in the context of fibrosis in sclerosis (SSc) as predictive disease biomarkers and regulators of ECM synthesis, with promising therapeutic potential. In this present review, an informative summary of major MCPs is presented highlighting their clear correlations to SSc- fibrosis.

Epigenetic Control of Scleroderma: Current Knowledge and Future Perspectives

PURPOSE OF REVIEW

Epigenetics has been implicated in the pathogenesis of systemic sclerosis (SSc). In this review, the involvement of the three epigenetic mechanisms in SSc development and progression-DNA methylation, histone modifications, and non-coding RNAs-will be discussed.

RECENT FINDINGS

Alteration in epigenetics was observed in immune cells, dermal fibroblasts, and endothelial cells derived from SSc patients. Genes that are affected include those involved in immune cell function and differentiation, TGFβ and Wnt pathways, extracellular matrix accumulation, transcription factors, and angiogenesis. All the studies remain in the pre-clinical stage. Extensive research provides evidence that epigenetic alterations are critical for SSc pathogenesis. Future epigenomic studies will undoubtedly continue to broaden our understanding of disease pathogenesis and clinical heterogeneity. They will also provide the scientific basis for repurposing epigenetic-modifying agents for SSc patients.

CCN1 expression by fibroblasts is required for bleomycin-induced skin fibrosis

The microenvironment contributes to the excessive connective tissue deposition that characterizes fibrosis. Members of the CCN family of matricellular proteins are secreted by fibroblasts into the fibrotic microenvironment; however, the role of endogenous CCN1 in skin fibrosis is unknown. Mice harboring a fibroblast-specific deletion for CCN1 were used to assess if CCN1 contributes to dermal homeostasis, wound healing, and skin fibrosis. Mice with a fibroblast-specific CCN1 deletion showed progressive skin thinning and reduced accumulation of type I collagen; however, the overall mechanical property of skin (Young's modulus) was not significantly reduced. Real time-polymerase chain reaction analysis revealed that CCN1-deficient skin displayed reduced expression of mRNAs encoding enzymes that promote collagen stability (including prolyl-4-hydroxylase and PLOD2), although expression of COL1A1 mRNA was unaltered. CCN1-deficent skin showed reduced hydroxyproline levels. Electron microscopy revealed that collagen fibers were disorganized in CCN1-deficient skin. CCN1-deficient mice were resistant to bleomycin-induced skin fibrosis, as visualized by reduced collagen accumulation and skin thickness suggesting that deposition/accumulation of collagen is impaired in the absence of CCN1. Conversely, CCN1-deficient mice showed unaltered wound closure kinetics, suggesting de novo collagen production in response to injury did not require CCN1. In response to either wounding or bleomycin, induction of α-smooth muscle actin-positive myofibroblasts was unaffected by loss of CCN1. CCN1 protein was overexpressed by dermal fibroblasts isolated from lesional (i.e., fibrotic) areas of patients with early onset diffuse scleroderma. Thus, CCN1 expression by fibroblasts, being essential for skin fibrosis, is a viable anti-fibrotic target.

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The role of endogenous CCN1 in skin biology is largely unknown

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Fibroblast-specific deletion CCN1 causes thinner skin and misaligned collagen

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CCN1-deficient mice were resistant to bleomycin-induced skin fibrosis

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Wound healing closure kinetics was unaffected by loss of CCN1

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CCN1 may be as a target for anti-fibrotic therapy