Dexamethasone induces trabecular meshwork cell myofibroblast transdifferentiation through ARHGEF26.

Glucocorticoid use may cause elevated intraocular pressure, leading to the development of glucocorticoid-induced glaucoma (GIG). However, the mechanism of GIG development remains incompletely understood. In this study, we subjected primary human trabecular meshwork cells (TMCs) and mice to dexamethasone treatment to mimic glucocorticoid exposure. The myofibroblast transdifferentiation of TMCs was observed in cellular and mouse models, as well as in human trabecular mesh specimens. This was demonstrated by the cytoskeletal reorganization, alterations in cell morphology, heightened transdifferentiation markers, increased extracellular matrix deposition, and cellular dysfunction. Knockdown of Rho guanine nucleotide exchange factor 26 (ARHGEF26) expression ameliorated dexamethasone-induced changes in cell morphology and upregulation of myofibroblast markers, reversed dysfunction and extracellular matrix deposition in TMCs, and prevented the development of dexamethasone-induced intraocular hypertension. And, this process may be related to the TGF-ß pathway. In conclusion, glucocorticoids induced the myofibroblast transdifferentiation in TMCs, which played a crucial role in the pathogenesis of GIG. Inhibition of ARHGEF26 expression protected TMCs by reversing myofibroblast transdifferentiation. This study demonstrated the potential of reversing the myofibroblast transdifferentiation of TMCs as a new target for treating GIG.

Effect of Topical Losartan in the Treatment of Established Corneal Fibrosis in Rabbits.

Purpose: The purpose of this study was to evaluate the safety and efficacy of topical losartan in the therapeutic treatment of established corneal scaring fibrosis at 1 month after alkali burn in rabbits. Methods: Standardized alkali burns were performed in 1 eye of 24 rabbits with 0.75N NaOH for 15 seconds. Corneas were allowed to heal and develop scaring of the cornea for 1 month. Twelve eyes per group were treated with 50 µL of topical 0.8 mg/mL losartan in balanced salt solution (BSS), pH 7.0, and 12 eyes were treated with vehicle BSS 6 times per day. Six corneas were analyzed at 1 week or 1 month in each group. Standardized slit lamp photographs were obtained at the end point for each cornea and opacity was quantitated using ImageJ. Corneoscleral rims were cryofixed in optimum cutting temperature (OCT) solution and combined duplex immunohistochemistry for myofibroblast marker alpha-smooth muscle actin (α-SMA), mesenchymal cell marker vimentin, and TUNEL assay for apoptosis was performed on all corneas. Results: Topical losartan was effective in the treatment of established stromal fibrosis following alkali burn injury to the rabbit cornea. Stromal myofibroblast density was decreased and stromal cell apoptosis was increased (included both α-SMA-positive myofibroblasts and α-SMA-negative, vimentin-positive cells) at both 1 week and 1 month in the topical losartan-treated compared with vehicle-treated groups. Conclusions: Topical losartan is effective in the treatment of established stromal fibrosis in rabbits. Most myofibroblasts disappear from the stroma within the first month of losartan treatment. Longer treatment with topical losartan is needed to allow time for corneal fibroblast regeneration of the epithelial basement membrane (in coordination with epithelial cells) and the removal of disordered extracellular matrix produced by myofibroblasts.

Spatial transcriptomic characterization of pathologic niches in IPF.

Despite advancements in antifibrotic therapy, idiopathic pulmonary fibrosis (IPF) remains a medical condition with unmet needs. Single-cell RNA sequencing (scRNA-seq) has enhanced our understanding of IPF but lacks the cellular tissue context and gene expression localization that spatial transcriptomics provides. To bridge this gap, we profiled IPF and control patient lung tissue using spatial transcriptomics, integrating the data with an IPF scRNA-seq atlas. We identified three disease-associated niches with unique cellular compositions and localizations. These include a fibrotic niche, consisting of myofibroblasts and aberrant basaloid cells, located around airways and adjacent to an airway macrophage niche in the lumen, containing SPP1+ macrophages. In addition, we identified an immune niche, characterized by distinct lymphoid cell foci in fibrotic tissue, surrounded by remodeled endothelial vessels. This spatial characterization of IPF niches will facilitate the identification of drug targets that disrupt disease-driving niches and aid in the development of disease relevant in vitro models.

Phosphodiesterase type 5 inhibitor tadalafil reduces prostatic fibrosis via MiR-3126-3p/FGF9 axis in benign prostatic hyperplasia.

Myofibroblast buildup and prostatic fibrosis play a crucial role in the development of benign prostatic hyperplasia (BPH). Treatments specifically targeting myofibroblasts could be a promising approach for treating BPH. Tadalafil, a phosphodiesterase type 5 (PDE5) inhibitor, holds the potential to intervene in this biological process. This study employs prostatic stromal fibroblasts to induce myofibroblast differentiation through TGFß1 stimulation. As a result, tadalafil significantly inhibited prostatic stromal fibroblast proliferation and fibrosis process, compared to the control group. Furthermore, our transcriptome sequencing results revealed that tadalafil inhibited FGF9 secretion and simultaneously improved miR-3126-3p expression via TGFß1 suppression. Overall, TGFß1 can trigger pro-fibrotic signaling through miR-3126-3p in the prostatic stroma, and the use of tadalafil can inhibit this process.

Rhizoma coptidis can inhibit the excessive proliferation, inflammation, and transformation of lung fibroblasts into myofibroblasts.

BACKGROUND: Pulmonary fibrosis (PF) is a chronic, progressive, and irreversible heterogeneous disease of lung interstitial tissue. To combat progression of PF, new drugs are required to be developed. Rhizoma coptidis (COP), one of the main alkaloids of Coptis chinensis, is a traditional herbal medicine used to treat various inflammatory diseases. OBJECTIVE: To investigate the possible effects of Coptisine (Cop) on the growth, inflammation, as well as FMT of TNF-ß1-induced HFL1 cells and uncover the mechanism. MATERIAL AND METHODS: Human fetal lung fibroblast 1 (HFL1) was induced using 6ng/mL TGF-ß1 as a model of pulmonary fibrosis. CCK-8, Brdu, and transwell assays indicated the effects on cell growth as well as motility. qPCR and the corresponding kits indicted the effects on cell inflammation. Immunoblot showed the effects on FMT and further confirmed the mechanism. RESULTS: Coptisine inhibits excessive growth as well as motility of TNF-ß1-induced HFL1 cells. It further inhibits inflammation and ROS levels in TNF-ß1-induced HFL1 cells. Coptisine inhibits the FMT process of TNF-ß1-induced HFL1 cells. Mechanically, coptisine promotes the Nrf2/HO-1 pathway. CONCLUSION: Coptisine can inhibit the excessive growth, inflammation as well as FMT of lung fibroblasts into myofibroblasts. It could serve as a promising drug of PF.

Targeting the transmembrane cytokine co-receptor neuropilin-1 in distal tubules improves renal injury and fibrosis.

Neuropilin-1 (NRP1), a co-receptor for various cytokines, including TGF-ß, has been identified as a potential therapeutic target for fibrosis. However, its role and mechanism in renal fibrosis remains elusive. Here, we show that NRP1 is upregulated in distal tubular (DT) cells of patients with transplant renal insufficiency and mice with renal ischemia-reperfusion (I-R) injury. Knockout of Nrp1 reduces multiple endpoints of renal injury and fibrosis. We find that Nrp1 facilitates the binding of TNF-α to its receptor in DT cells after renal injury. This signaling results in a downregulation of lysine crotonylation of the metabolic enzyme Cox4i1, decreases cellular energetics and exacerbation of renal injury. Furthermore, by single-cell RNA-sequencing we find that Nrp1-positive DT cells secrete collagen and communicate with myofibroblasts, exacerbating acute kidney injury (AKI)-induced renal fibrosis by activating Smad3. Dual genetic deletion of Nrp1 and Tgfbr1 in DT cells better improves renal injury and fibrosis than either single knockout. Together, these results reveal that targeting of NRP1 represents a promising strategy for the treatment of AKI and subsequent chronic kidney disease.

Pulmonary matrix-derived hydrogels from patients with idiopathic pulmonary fibrosis induce a proinflammatory state in lung fibroblasts in vitro.

Idiopathic pulmonary fibrosis (IPF), one of the most common forms of interstitial lung disease, is a poorly understood, chronic, and often fatal fibroproliferative condition with only two FDA-approved medications. Understanding the pathobiology of the fibroblast in IPF is critical to evaluating and discovering novel therapeutics. Using a decellularized lung matrix derived from patients with IPF, we generate three-dimensional hydrogels as in vitro models of lung physiology and characterize the phenotype of fibroblasts seeded into the hydrogels. When cultured in IPF extracellular matrix hydrogels, IPF fibroblasts display differential contractility compared with their normal counterparts, lose the classical myofibroblast marker α-smooth muscle actin, and increase expression of proinflammatory cytokines compared with fibroblasts seeded two-dimensionally on tissue culture dishes. We validate this proinflammatory state in fibroblast-conditioned media studies with monocytes and monocyte-derived macrophages. These findings add to a growing understanding of the lung microenvironment effect on fibroblast phenotypes, shed light on the potential role of fibroblasts as immune signaling hubs during lung fibrosis, and suggest intervention in fibroblast-immune cell cross-talk as a possible novel therapeutic avenue.

[Pathogenesis of pulmonary fibrosis]. / Patogenez fibroza legkikh.

A literature review reflects data on the mechanisms of pulmonary fibrosis after a novel coronavirus infection associated with the SARS-COV2 virus. Factors contributing to post-COVID lung remodeling are considered. According to the literature, in the mechanism of pulmonary fibrosis, during the course of the disease and during the recovery period, both direct viral damage and death of alveolocytes and endothelium, the development of a systemic inflammatory reaction due to inadequate secretion of cytokines, especially type 2, which are activators of the proliferation of fibroblasts and myofibroblasts, are important. The influence of angiogenesis disorders and vascular dysfunction on pneumofibrosis was noted. Attention is also paid to the relationship between the development of pulmonary fibrosis and abnormal activation of the renin-angiotensin-aldosterone system. In combination with the action of many factors, especially germinal ones, an imbalance between profibrogenic and antifibrogenic action develops and fibrosis occurs.

Human amniotic membrane modulates collagen production and deposition in vitro.

Pathological fibrosis is a significant complication of surgical procedures resulting from the accumulation of excess collagen at the site of repair which can compromise the tissue architecture and severely impede the function of the affected tissue. Few prophylactic treatments exist to counteract this process; however, the use of amniotic membrane allografts has demonstrated promising clinical outcomes. This study aimed to identify the underlying mechanism of action by utilizing relevant models that accurately represent the pathophysiology of the disease state. This study employed a pro-fibrotic in vitro system using TGFß1 stimulation and macromolecular crowding techniques to evaluate the mechanism by which amniotic membrane allografts regulate collagen biosynthesis and deposition. Following treatment with dehydrated human amnion chorion membrane (DHACM), subsequent RNA sequencing and functional enrichment with Reactome pathway analysis indicated that amniotic membranes are indeed capable of regulating genes associated with the composition and function of the extracellular matrix. Furthermore, macromolecular crowding was used in vitro to expand the evaluation to include both the effects of DHACM and a lyophilized human amnion/chorion membrane (LHACM). DHACM and LHACM regulate the TGFß pathway and myofibroblast differentiation. Additionally, both DHACM and LHACM modulate the production, secretion, and deposition of collagen type I, a primary target for pathological fibrosis. These observations support the hypothesis that amniotic membranes may interrupt pathological fibrosis by regulating collagen biosynthesis and associated pathways.

Regulation of myofibroblast dedifferentiation in pulmonary fibrosis.

Idiopathic pulmonary fibrosis is a lethal, progressive, and irreversible condition that has become a significant focus of medical research due to its increasing incidence. This rising trend presents substantial challenges for patients, healthcare providers, and researchers. Despite the escalating burden of pulmonary fibrosis, the available therapeutic options remain limited. Currently, the United States Food and Drug Administration has approved two drugs for the treatment of pulmonary fibrosis-nintedanib and pirfenidone. However, their therapeutic effectiveness is limited, and they cannot reverse the fibrosis process. Additionally, these drugs are associated with significant side effects. Myofibroblasts play a central role in the pathophysiology of pulmonary fibrosis, significantly contributing to its progression. Consequently, strategies aimed at inhibiting myofibroblast differentiation or promoting their dedifferentiation hold promise as effective treatments. This review examines the regulation of myofibroblast dedifferentiation, exploring various signaling pathways, regulatory targets, and potential pharmaceutical interventions that could provide new directions for therapeutic development.

DKK1 loss promotes endometrial fibrosis via autophagy and exosome-mediated macrophage-to-myofibroblast transition.

INTRODUCTION: Intrauterine adhesions (IUA) manifest as endometrial fibrosis, often causing infertility or recurrent miscarriage; however, their pathogenesis remains unclear. OBJECTIVES: This study assessed the role of Dickkopf WNT signaling pathway inhibitor 1 (DKK1) and autophagy in endometrial fibrosis, using clinical samples as well as in vitro and in vivo experiments. METHODS: Immunohistochemistry, immunofluorescence and western blot were used to determine the localization and expression of DKK1 in endometrium; DKK1 silencing and DKK1 overexpression were used to detect the biological effects of DKK1 silencing or expression in endometrial cells; DKK1 gene knockout mice were used to observe the phenotypes caused by DKK1 gene knockout. RESULTS: In patients with IUA, DKK1 and autophagy markers were down-regulated; also, α-SMA and macrophage localization were increased in the endometrium. DKK1 conditional knockout (CKO) mice showed a fibrotic phenotype with decreased autophagy and increased localization of α-SMA and macrophages in the endometrium. In vitro studies showed that DKK1 knockout (KO) suppressed the autophagic flux of endometrial stromal cells. In contrast, ectopic expression of DKK1 showed the opposite phenotype. Mechanistically, we discovered that DKK1 regulates autophagic flux through Wnt/ß-catenin and PI3K/AKT/mTOR pathways. Further studies showed that DKK1 KO promoted the secretion of interleukin (IL)-8 in exosomes, thereby promoting macrophage proliferation and metastasis. Also, in DKK1 CKO mice, treatment with autophagy activator rapamycin partially restored the endometrial fibrosis phenotype. CONCLUSION: Our findings indicated that DKK1 was a potential diagnostic marker or therapeutic target for IUA.

Graphene Quantum Dots Reduce Hypertrophic Scar by Inducing Myofibroblasts To Be a Quiescent State.

Contrary to the initial belief that myofibroblasts are terminally differentiated cells, myofibroblasts have now been widely recognized as an activation state that is reversible. Therefore, strategies targeting myofibroblast to be a quiescent state may be an effective way for antihypertrophic scar therapy. Graphene quantum dots (GQDs), a novel zero-dimensional and carbon-based nanomaterial, have recently garnered significant interest in nanobiomedicine, owing to their excellent biocompatibility, tunable photoluminescence, and superior physiological stability. Although multiple nanoparticles have been used to alleviate hypertrophic scars, a GQD-based therapy has not been reported. Our in vivo studies showed that GQDs exhibited significant antiscar efficacy, with scar appearance improvement, collagen reduction and rearrangement, and inhibition of myofibroblast overproliferation. Further in vitro experiments revealed that GQDs inhibited α-SMA expression, collagen synthesis, and cell proliferation and migration, inducing myofibroblasts to become quiescent fibroblasts. Mechanistic studies have demonstrated that the effect of GQDs on myofibroblast proliferation blocked cell cycle progression by disrupting the cyclin-CDK-E2F axis. This study suggests that GQDs, which promote myofibroblast-to-fibroblast transition, could be a novel antiscar nanomedicine for the treatment of hypertrophic scars and other types of pathological fibrosis.

Liver Fibrosis: From Basic Science towards Clinical Progress, Focusing on the Central Role of Hepatic Stellate Cells.

The burden of chronic liver disease is globally increasing at an alarming rate. Chronic liver injury leads to liver inflammation and fibrosis (LF) as critical determinants of long-term outcomes such as cirrhosis, liver cancer, and mortality. LF is a wound-healing process characterized by excessive deposition of extracellular matrix (ECM) proteins due to the activation of hepatic stellate cells (HSCs). In the healthy liver, quiescent HSCs metabolize and store retinoids. Upon fibrogenic activation, quiescent HSCs transdifferentiate into myofibroblasts; lose their vitamin A; upregulate α-smooth muscle actin; and produce proinflammatory soluble mediators, collagens, and inhibitors of ECM degradation. Activated HSCs are the main effector cells during hepatic fibrogenesis. In addition, the accumulation and activation of profibrogenic macrophages in response to hepatocyte death play a critical role in the initiation of HSC activation and survival. The main source of myofibroblasts is resident HSCs. Activated HSCs migrate to the site of active fibrogenesis to initiate the formation of a fibrous scar. Single-cell technologies revealed that quiescent HSCs are highly homogenous, while activated HSCs/myofibroblasts are much more heterogeneous. The complex process of inflammation results from the response of various hepatic cells to hepatocellular death and inflammatory signals related to intrahepatic injury pathways or extrahepatic mediators. Inflammatory processes modulate fibrogenesis by activating HSCs and, in turn, drive immune mechanisms via cytokines and chemokines. Increasing evidence also suggests that cellular stress responses contribute to fibrogenesis. Recent data demonstrated that LF can revert even at advanced stages of cirrhosis if the underlying cause is eliminated, which inhibits the inflammatory and profibrogenic cells. However, despite numerous clinical studies on plausible drug candidates, an approved antifibrotic therapy still remains elusive. This state-of-the-art review presents cellular and molecular mechanisms involved in hepatic fibrogenesis and its resolution, as well as comprehensively discusses the drivers linking liver injury to chronic liver inflammation and LF.

ADAM15 in Fibroblasts: Improving the Matrix Remodeling by Blocking the Action of Transforming Growth Factor-ß1.

OBJECTIVE: During the progression of chronic idiopathic pulmonary fibrosis (IPF), maladaptive tissue remodeling including excessive extracellular matrix (ECM) deposition occurs, which eventually leads to architectural distortion and loss of organ function in organ fibrosis. ADAM15, which is highly expressed in the developing lungs and kidneys, is a transmembrane-anchored multidomain protein belonging to the family of metalloproteinases. Compared to the extensive studies about functions of matrix metalloproteinases (MMPs), less are discussed about ADAM15, particularly in function and mechanism involving fibrogenesis. Our study aims to fill in this gap. METHODS: We identified ADAM15 as a novel antifibrotic mediator in lung fibrosis. We found that ADAM15 has cross-talks with transforming growth factor-ß1 (TGF-ß1), which is the most potent profibrotic mediator. We provided molecular and translational evidence that knockdown of ADAM15 accelerated fibrogenic response induced by TGF-ß1 and upregulation of ADAM15 rescued TGF-ß1-induced myofibroblast activation in part. RESULTS: Overexpression of ADAM15 ameliorates fibrotic changes and ADAM15 deficiency exacerbates changes from fibroblast to myofibroblast in NIH/3T3. Results were also presented and identified by the intuitive immunofluorescence staining. CONCLUSION: In this study, we uncover a new molecular mechanism of tissue fibrogenesis and identify ADAM15 as a potential therapeutic target in the treatment of fibrotic diseases.

Procyanidin C1 inhibits bleomycin-induced pulmonary fibrosis in mice by selective clearance of senescent myofibroblasts.

Pulmonary fibrosis is a formidable challenge in chronic and age-related lung diseases. Myofibroblasts secrete large amounts of extracellular matrix and induce pro-repair responses during normal wound healing. Successful tissue repair results in termination of myofibroblast activity via apoptosis; however, some myofibroblasts exhibit a senescent phenotype and escape apoptosis, causing over-repair that is characterized by pathological fibrotic scarring. Therefore, the removal of senescent myofibroblasts using senolytics is an important method for the treatment of pulmonary fibrosis. Procyanidin C1 (PCC1) has recently been discovered as a senolytic compound with very low toxicity and few side effects. This study aimed to determine whether PCC1 could improve lung fibrosis by promoting apoptosis in senescent myofibroblasts and to investigate the mechanisms involved. The results showed that PCC1 attenuates bleomycin (BLM)-induced pulmonary fibrosis in mice. In addition, we found that PCC1 inhibited extracellular matrix deposition and promoted the apoptosis of senescent myofibroblasts by increasing PUMA expression and activating the BAX signaling pathway. Our findings represent a new method of pulmonary fibrosis management and emphasize the potential of PCC1 as a senotherapeutic agent for the treatment of pulmonary fibrosis, providing hope for patients with pulmonary fibrosis worldwide. Our results advance our understanding of age-related diseases and highlight the importance of addressing cellular senescence in treatment.

[Mechanisms by which Mettl3 regulates pericyte-myofibroblast transdifferentiation through PI3K/AKT signaling pathway].

Objective: To investigate the role and underlying mechanisms of methyltransferase (Mettl) 3 in the process of angiotensin Ⅱ (Ang Ⅱ)-induced pericyte-to-myofibroblast transdifferentiation and renal fibrosis. Methods: C57BL/6J mice were used, in cell experiments, mouse renal pericytes were isolated and cultured using magnetic bead sorting. These pericytes were then induced to transdifferentiate into myofibroblasts with 1×106 mmol/L Ang Ⅱ, which was the Ang Ⅱ group, while pericytes cultured in normal conditions served as the control group. Successful transdifferentiation was verified by immunofluorescence staining, Western blotting, and real-time reverse transcription PCR (RT-qPCR) for α-smooth muscle actin (α-SMA). The levels of m6A modifications and related enzymes (Mettl3, Mettl14), Wilms tumor 1-associated protein (WTAP), fat mass and obesity protein (FTO), ALKBH5, YTHDF1, YTHDF2, YTHDC1, YTHDC2, YTHDC3 were assessed by Dot blot, RT-qPCR and Western blot. Mettl3 expression was inhibited in cells using lentivirus-mediated Mettl3-shRNA transfection, creating sh-Mettl3 and Ang Ⅱ+sh-Mettl3 groups, while lentivirus empty vector transfection served as the negative control (Ang Ⅱ+sh-NC group). The impact of Ang Ⅱ on pericyte transdifferentiation was observed, and the expression of downstream phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway proteins, including PI3K, AKT, phosphorylated AKT at serine 473 (p-AKT (S473)), and phosphorylated AKT at threonine 308 (p-AKT (T308)), were examined. PI3K gene transcription was inhibited by co-culturing cells with actinomycin D, and the half-life of PI3K mRNA was calculated by measuring residual PI3K mRNA expression over different co-culture time. The reversibility of Mettl3 inhibition on Ang Ⅱ-induced pericyte-to-myofibroblast transdifferentiation was assessed by adding the AKT activator SC79 to the Ang Ⅱ+sh-Mettl3 group. In animal experiments, mice were divided into these groups: sham group (administered 0.9% sterile saline), Ang Ⅱ group (infused with Ang Ⅱ solution), sh-Mettl3 group (injected with Mettl3 shRNA lentivirus solution), Ang Ⅱ+sh-Mettl3 group (infused with Ang Ⅱ solution and injected with Mettl3 shRNA lentivirus solution), and Ang Ⅱ+sh-Mettl3+SC79 group (administered Ang Ⅱ solution and Mettl3 shRNA lentivirus, with an additional injection of SC79). Each group consisted of six subject mice. Blood pressure was measured using the tail-cuff method before and after surgery, and serum creatinine, urea, and urinary albumin levels were determined 4 weeks post-surgery. Kidney tissues were collected at 28 days and stained using hematoxylin-eosin (HE) and Masson's trichrome to assess the extent of renal fibrosis. Results: Primary renal pericytes were successfully obtained by magnetic bead sorting, and intervened with 1×106 mmol/L Ang Ⅱ for 48 hours to induce pericyte-to-myofibroblast transdifferentiation. Dot blot results indicated higher m6A modification levels in the Ang Ⅱ group compared to the control group (P<0.05). RT-qPCR and Western blot results showed upregulation of Mettl3 mRNA and protein levels in the Ang Ⅱ group compared to the control group (both P<0.05). In the Ang Ⅱ+sh-Mettl3 group, Mettl3 protein expression was lower than that in the Ang Ⅱ group, with reduced expression levels of α-SMA, vimentin, desmin, fibroblast agonist protein (FAPa) and type Ⅰ collagen (all P<0.05). Compared to the control group, PI3K mRNA expression level was elevated in the Ang Ⅱ group, along with increased p-AKT (S473) and p-AKT (T308) expressions. In the Ang Ⅱ+sh-Mettl3 group, PI3K mRNA expression and p-AKT (S473) and p-AKT (T308) levels were decreased (all P<0.05). The half-life of PI3K mRNA was shorter in the Ang Ⅱ+sh-Mettl3 group than that in the Ang Ⅱ+sh-NC group (2.34 h vs. 3.42 h). The ameliorative effect of Mettl3 inhibition on Ang Ⅱ-induced pericyte-to-myofibroblast transdifferentiation was reversible by SC79. Animal experiments showed higher blood pressure, serum creatinine, urea, and 24-hour urinary protein levels, and a larger fibrosis area in the Ang Ⅱ group compared to the sham group (all P<0.05). The fibrosis area was smaller in the Ang Ⅱ+sh-Mettl3 group than that in the Ang Ⅱ group (P<0.05), but increased again upon addition of SC79. Conclusion: Mettl3-mediated RNA m6A epigenetic regulation is involved in Ang Ⅱ-induced pericyte-to-myofibroblast transdifferentiation and renal fibrosis, potentially by affecting PI3K stability and regulating the PI3K/AKT signaling pathway.

Nintedanib Mitigates Radiation-Induced Pulmonary Fibrosis by Suppressing Epithelial Cell Inflammatory Response and Inhibiting Fibroblast-to-Myofibroblast Transition.

Radiation-induced pulmonary fibrosis (RIPF) represents a serious complication observed in individuals undergoing thoracic radiation therapy. Currently, effective interventions for RIPF are unavailable. Prior research has demonstrated that nintedanib, a Food and Drug Administration (FDA)-approved anti-fibrotic agent for idiopathic pulmonary fibrosis, exerts therapeutic effects on chronic fibrosing interstitial lung disease. This research aimed to investigate the anti-fibrotic influences of nintedanib on RIPF and reveal the fundamental mechanisms. To assess its therapeutic impact, a mouse model of RIPF was established. The process involved nintedanib administration at various time points, both prior to and following thoracic radiation. In the RIPF mouse model, an assessment was conducted on survival rates, body weight, computed tomography features, histological parameters, and changes in gene expression. In vitro experiments were performed to discover the mechanism underlying the therapeutic impact of nintedanib on RIPF. Treatment with nintedanib, administered either two days prior or four weeks after thoracic radiation, significantly alleviated lung pathological changes, suppressed collagen deposition, and improved the overall health status of the mice. Additionally, nintedanib demonstrated significant mitigation of radiation-induced inflammatory responses in epithelial cells by inhibiting the PI3K/AKT and MAPK signaling pathways. Furthermore, nintedanib substantially inhibited fibroblast-to-myofibroblast transition by suppressing the TGF-ß/Smad and PI3K/AKT/mTOR signaling pathways. These findings suggest that nintedanib exerts preventive and therapeutic effects on RIPF by modulating multiple targets instead of a single anti-fibrotic pathway and encourage the further clinical trials to determine the efficacy of nintedanib in patients with RIPF.

The Role of Vimentin in Human Corneal Fibroblast Spreading and Myofibroblast Transformation.

Vimentin has been reported to play diverse roles in cell processes such as spreading, migration, cell-matrix adhesion, and fibrotic transformation. Here, we assess how vimentin impacts cell spreading, morphology, and myofibroblast transformation of human corneal fibroblasts. Overall, although knockout (KO) of vimentin did not dramatically impact corneal fibroblast spreading and mechanical activity (traction force), cell elongation in response to PDGF was reduced in vimentin KO cells as compared to controls. Blocking vimentin polymerization using Withaferin had even more pronounced effects on cell spreading and also inhibited cell-induced matrix contraction. Furthermore, although absence of vimentin did not completely block TGFß-induced myofibroblast transformation, the degree of transformation and amount of αSMA protein expression was reduced. Proteomics showed that vimentin KO cells cultured in TGFß had a similar pattern of protein expression as controls. One exception included periostin, an ECM protein associated with wound healing and fibrosis in other cell types, which was highly expressed only in Vim KO cells. We also demonstrate for the first time that LRRC15, a protein previously associated with myofibroblast transformation of cancer-associated fibroblasts, is also expressed by corneal myofibroblasts. Interestingly, proteins associated with LRRC15 in other cell types, such as collagen, fibronectin, ß1 integrin and α11 integrin, were also upregulated. Overall, our data show that vimentin impacts both corneal fibroblast spreading and myofibroblast transformation. We also identified novel proteins that may regulate corneal myofibroblast transformation in the presence and/or absence of vimentin.

EBF1-COX4I2 signaling axis promotes a myofibroblast-like phenotype in cancer-associated fibroblasts (CAFs) and is associated with an immunosuppressive microenvironment.

Immunotherapy has limited response rates in colorectal cancer (CRC) due to an immunosuppressive tumor microenvironment (TME). Combining transcriptome sequencing, clinical specimens, and functional experiments, we identified a unique group of CAF subpopulations (COX4I2 + ) with inhibited mitochondrial respiration and enhanced glycolysis. Through bioinformatics predictions and luciferase reporter assays, we determined that EBF1 can upstreamly regulate COX4I2 transcription. COX4I2 + CAFs functionally and phenotypically resemble myofibroblasts, are important for the formation of the fibrotic TME, and are capable of activating the M2 phenotype of macrophages. In vitro experiments demonstrated that COX4I2 + CAFs promote immunosuppressive TME by blocking CD8 + T cell infiltration and inducing CD8 + T cell dysfunction. Using multiple independent cohorts, we also found a strong correlation between the immunotherapy response rate of CRC patients and COX4I2 expression in their tumors. Our results identify a CAF subpopulation characterized by activation of the EBF1-COX4I2 axis, and this group of CAFs can be targeted to improve cancer immunotherapy outcomes.

The roles of orphan nuclear receptor 4 group A1 and A2 in fibrosis.

Fibrosis is not a disease but rather an outcome of the pathological tissue repair response. Many myofibroblasts are activated which lead to the excessive accumulation of extracellular matrix components such as collagen and fibronectin with fibrosis. A variety of organs, including kidney, liver, lung, heart and skin, can undergo fibrosis under the stimulation of exogenous or endogenous pathogenic factors. The orphan nuclear receptor 4 group A1 (NR4A1) and nuclear receptor 4 group A2（NR4A2）are belong to the nuclear receptor subfamily and inhibit the occurrence and development of fibrosis. NR4A1 is an inhibitory factor of TGF-ß signaling transduction. Overexpression of NR4A1 in fibroblasts can reduce TGF-ß induced collagen deposition and fibrosis related gene expression. Here, we summarize the current research progress on the NR4A1/2 and fibrosis, providing reference for the treatment of fibrosis.