Single-cell transcriptome sequencing-based analysis: probing the mechanisms of glycoprotein NMB regulation of epithelial cells involved in silicosis.

Chronic exposure to silica can lead to silicosis, one of the most serious occupational lung diseases worldwide, for which there is a lack of effective therapeutic drugs and tools. Epithelial mesenchymal transition plays an important role in several diseases; however, data on the specific mechanisms in silicosis models are scarce. We elucidated the pathogenesis of pulmonary fibrosis via single-cell transcriptome sequencing and constructed an experimental silicosis mouse model to explore the specific molecular mechanisms affecting epithelial mesenchymal transition at the single-cell level. Notably, as silicosis progressed, glycoprotein non-metastatic melanoma protein B (GPNMB) exerted a sustained amplification effect on alveolar type II epithelial cells, inducing epithelial-to-mesenchymal transition by accelerating cell proliferation and migration and increasing mesenchymal markers, ultimately leading to persistent pulmonary pathological changes. GPNMB participates in the epithelial-mesenchymal transition in distant lung epithelial cells by releasing extracellular vesicles to accelerate silicosis. These vesicles are involved in abnormal changes in the composition of the extracellular matrix and collagen structure. Our results suggest that GPNMB is a potential target for fibrosis prevention.

The Combined Effects of Circular RNA Methylation Promote Pulmonary Fibrosis.

m6A (N6-methyladenosine) is the most common type of RNA methylation modification, mainly occurring on mRNA. Whether m6A-modified circular RNAs (circRNAs) are involved in pulmonary fibrosis in different settings remains unclear. Using an m6A-circRNA epitranscriptomic chip, candidate circRNAs were selected, among which hsa_circ_0000672 and hsa_circ_0005654 were specifically involved in SiO2-induced pulmonary fibrosis by targeting the same protein, eIF4A3, indicating that the m6A modification of these two circRNAs has a synergistic effect on fibroblast dysfunction induced by SiO2. A mechanistic study revealed that the m6A modification of circRNAs was mainly mediated by the methyltransferase METTL3. Furthermore, METTL3 promoted the activation, migration, and activity of pulmonary fibroblasts and participated in SiO2-induced pulmonary fibrosis via the circRNA m6A modification. m6A methylation of circRNAs mediates silica-induced fibrosis, enriching the understanding of circRNAs and uncovering a potential new target for treating fibrosis-related diseases.

Customers' risk perception and dine-out motivation during a pandemic: Insight for the restaurant industry.

The restaurant industry is one of the most affected businesses during the outbreak of COVID-19. The customer choice regarding whether or not to dine in a restaurant have changed due to this unprecedented global pandemic. Integrated with the affective decision-making framework, meta-theoretic model of motivation (3M), and optimistic bias theory, this conceptual paper proposes a theoretical scheme for understanding constructs that affect consumer motivation while considering the significance of consumers' risk perceptions of the novel coronavirus disease. This research aims to delineate the role of loyalty, trust, and transparency on resuming in-restaurant dining during and after the pandemic. By identifying the link between each construct and addressing the unparalleled food-/health related risks, this study suggests that restaurants who accumulated more customer trust by fostering transparency are likely to have more business and quickly recover from the shock.

circDLPAG4/HECTD1 mediates ischaemia/reperfusion injury in endothelial cells via ER stress.

Background: Vascular endothelial cell dysfunction, characterized by cell apoptosis and migration, plays a crucial role in ischaemia/reperfusion (I/R) injury, a common aspect of cardiovascular diseases. Recent studies have suggested that non-coding RNAs, such as circular RNAs (circRNA), play a role in cell dysfunction in I/R injury, although the detailed mechanism is unclear.Methods: Human umbilical vein endothelial cells (HUVECs) were used for in vitro I/R model. Protein expression was detected by western blotting (WB) and immunocytochemistry. The CRISPR/Cas9 system, WB, cell viability assays, Hoechst staining and a 3D migration model were used to explore functional changes. RNA expression was evaluated using quantitative real-time PCR and a FISH assay combined with lentivirus transfection regulating circRNAs and miRNAs. A mouse myocardial I/R model using C57 mice was established to confirm the in vitro findings.Results: In HUVECs, I/R induced a significant time-dependent decrease in HECTD1 associated with an approximately 45% decrease in cell viability and increases in cell apoptosis and migration, which were attenuated by HECTD1 overexpression. I/R-induced upregulation of endoplasmic reticulum stress was also attenuated HECTD1 overexpression. Moreover, miR-143 mimics inhibited HECTD1 expression, which was restored by circDLGAP4 overexpression, providing insight as to the molecular mechanism of I/R-induced HECTD1 in endothelial cell dysfunction.Conclusion: Our results suggest a critical role for circDLGAP4 and HECTD1 in endothelial cell dysfunction induced by I/R, providing novel insight into potential therapeutic targets for the treatment of myocardial ischaemia.

SPIO nanoparticle-labeled bone marrow mesenchymal stem cells inhibit pulmonary EndoMT induced by SiO2.

Endothelial-mesenchymal transition (EndoMT) is a key step during lung fibrosis. Studies have shown that bone marrow mesenchymal stem cells (BMSCs) may act as therapeutic candidates for lung fibrosis. However, the effects of BMSCs on EndoMT induced by SiO2 have not been elucidated, and means to label and track grafted cells have been lacking. The current study explored whether BMSCs prevented pulmonary fibrosis by targeting EndoMT, as well as analyzed the distribution of BMSCs labeled with superparamagnetic iron oxide (SPIO) nanoparticles during treatment. TIE2-GFP mice, human umbilical vein endothelial cells (HUVECs), and BMSCs labeled with SPIO nanoparticles were used to explore the distributions and therapeutic effects of BMSCs in vivo and in vitro. We found that BMSCs reversed lung fibrosis by targeting EndoMT in vivo. Furthermore, we show that BMSCs labeled with SPIO nanoparticles could be used to track stem cells reliably in the lungs for 14 days. Conditioned medium from BMSCs attenuated the increased functional changes and reversed the SiO2-induced upregulation of ER stress and autophagy markers irrespective of whether they were nanoparticle labeled or not. Our findings identify novel methods to track labeled BMSCs with therapeutic potential.

CircRNA-012091/PPP1R13B-mediated Lung Fibrotic Response in Silicosis via Endoplasmic Reticulum Stress and Autophagy.

Silicosis is a progressive fibrotic disease of lung tissue caused by long-term inhalation of SiO2. However, relatively few studies of the direct effects of SiO2 on lung fibroblasts have been performed. PPP1R13B is a major member of the apoptosis-stimulating proteins of the p53 family, but its role in pulmonary fibrosis is unclear. To elucidate the role of PPP1R13B in the pathological process of silicosis, we explored the molecular mechanisms related to PPP1R13B and the functional effects of proliferation and migration of fibroblasts. Through lentivirus transfection, Western blotting, and fluorescent in situ hybridization experiments, we found that SiO2 downregulated circRNA-012091 (circ-012091) expression in lung fibroblasts and induced upregulation of downstream PPP1R13B. Transfection of L929 cells with PPP1R13B CRISPR NIC plasmid inhibited the upregulation of endoplasmic reticulum stress (ERS) and autophagy-related protein expression in lung fibroblasts treated with SiO2, and induced decreases in cell proliferation, migration, and viability. Transfection of L929 cells with the PPP1R13B CRISPR ACT plasmid induced increases in cell proliferation, migration, and viability. In addition, the ERS inhibitor salubrinal and the autophagy inhibitor 3-methyladenine inhibited the increased migration of L929 cells transfected with the PPP1R13B CRISPR ACT plasmid. These results suggest that PPP1R13B regulated by circ-012091 promotes the proliferation and migration of lung fibroblasts through ERS and autophagy, and plays a crucial role in the development of pulmonary fibrosis in silicosis.

Silica-induced initiation of circular ZC3H4 RNA/ZC3H4 pathway promotes the pulmonary macrophage activation.

Phagocytosis of silicon dioxide (SiO2) into lung cells causes an inflammatory cascade that results in fibroblast proliferation and migration, followed by fibrosis. Circular RNAs (circRNAs) are a subclass of noncoding RNAs that are present within mammalian cells; however, researchers have not determined whether circRNAs are involved in the pathophysiologic process of silicosis. To elucidate the role of these RNAs in SiO2-induced inflammation in pulmonary macrophages, we investigated the upstream molecular mechanisms and functional effects of circRNAs on cell apoptosis, proliferation, and migration. Primary cultures of alveolar macrophages from healthy donors and from patients and the RAW264.7 macrophage cell line were used to explore the functions of circZC3H4 RNA in macrophage activation. The experimental results indicated the following: 1) SiO2 concomitantly increased circZC3H4 RNA expression and increased ZC3H4 protein levels; 2) circular ZC3H4 (circZC3H4) RNA and ZC3H4 protein participated in SiO2-induced macrophage activation; and 3) SiO2-activated macrophages promoted fibroblast proliferation and migration via the circZC3H4 RNA/ZC3H4 pathway. The up-regulation of the ZC3H4 protein was confirmed in tissue samples from patients with silicosis. Our study elucidates a link between SiO2-induced macrophage activation and the circZC3H4 RNA/ZC3H4 pathway, thereby providing novel insight into the potential use of ZC3H4 to develop novel therapeutic strategies for silicosis.-Yang, X., Wang, J., Zhou, Z., Jiang, R., Huang, J., Chen, L., Cao, Z., Chu, H., Han, B., Cheng, Y., Chao, J. Silica-induced initiation of circular ZC3H4 RNA/ZC3H4 pathway promotes the pulmonary macrophage activation.

AQP4-knockout aggravation of isoprenaline-induced myocardial injury is mediated by p66Shc and endoplasmic reticulum stress.

Aquaporin 4 (AQP4) is a type of water channel protein that maintains the water balance of cardiomyocytes. However, the physiological role of AQP4 in cardiovascular disease is poorly understood. We wanted to explore whether p66Shc and endoplasmic reticulum stress participates in AQP4 knockout (KO)-mediated cardiac injury. There were two types of mice: AQP4 knockout and wild-type mice. Each type was randomly divided into three groups: Control group, isoprenaline stimulation group (ISO, 1 mg/kg, s.c., 5 days), and apocynin treatment group (APO, 100 mg/kg, p.o., 3 days). H9c2 rat cardiomyocytes were cultured for RNA interference of AQP4. Results showed increased left ventricular weight index and more severe myocardial inflammation were induced in AQP4 knockout mice relative to wild-type mice, accompanied by significantly increased levels of the oxidative stress biomarkers MDA and NOX4. In addition, the expressions of p66Shc, ER stress markers PERK, GRP78 and CHOP and proinflammatory factors such as ETA , IL6 and TNFα were upregulated in the myocardium of AQP4 knockout mice or AQP4 siRNA treated cardiomyocytes, whereas CASQ2 was downregulated. ISO stimulation aggravated these abnormalities, which were significantly attenuated by apocynin. This study showed that AQP4 knockout mice were susceptible to cardiac injury induced by ISO. The mechanism was closely connected with p66Shc and proinflammatory factors. Endoplasmic reticulum stress was also involved in the pathological process.

MCPIP1 mediates silica-induced cell migration in human pulmonary fibroblasts.

Silicosis is a systemic disease caused by inhaling silicon dioxide (SiO2). Phagocytosis of SiO2 in the lungs initiates an inflammatory cascade that results in fibroblast proliferation and migration followed by fibrosis. According to previous data from our laboratory, monocyte chemotactic protein-1 (MCP-1) plays a critical role in fibroblast proliferation and migration in conventional two-dimensional (2D) monolayer cultures. The present study aimed to explore the downstream cascade of MCP-1 in both 2D and three-dimensional (3D) cell culture models of silicosis. Experiments using primary cultured adult human pulmonary fibroblasts (HPF-a) demonstrated the following: 1) SiO2 treatment induces expression of MCP-1-induced protein (MCPIP1) in a time- and dose-dependent manner in both 2D and 3D cultures; 2) the MAPK and phosphatidylinositol-3-kinase (PI3K)/Akt pathways are involved in SiO2-induced MCPIP1 expression; and 3) MCPIP1 induction mediates the SiO2-induced increase in cell migration in both 2D and 3D cultures. The effect of MCP-1 in silicosis occurs mainly through MCPIP1, which, in turn, mediates the observed SiO2-induced increase in pulmonary fibroblast migration. However, the time frame for MCPIP1 induction differed between 2D and 3D cultures, indicating that, compared with conventional 2D cell culture systems, 3D culture may be useful for analyses of fibroblast physiology under conditions that more closely resemble in vivo environments. Our study determined the link between fibroblast-derived MCPIP1 and SiO2-induced cell migration, and this finding provides novel evidence of the potential of MCPIP1 in the development of novel therapeutic strategies for silicosis.

Role of MCPIP1 in the Endothelial-Mesenchymal Transition Induced by Silica.

BACKGROUND: Silicosis is characterized by the accumulation of fibroblasts and the excessive deposition of extracellular matrix. Fibroblast generation via endothelial-mesenchymal transition (EndMT) is one process responsible for this accumulation of fibroblasts. However, the mechanisms underlying EndMT remain unknown. METHODS: Human umbilical vein endothelial cells (HUVECs) were exposed to SiO2 (50 µg/cm2). Specific endothelial and mesenchymal markers were evaluated using immunofluorescence and western blot analysis. Functional changes were evaluated by analyzing cell migration and proliferation. LC3-adenovirus transfections were performed, and changes in autophagy were measured using a marker of autophagy. RESULTS: SiO2 induced decreases in the endothelial cell-specific markers in HUVECs while dramatically increasing mesenchymal cell product levels and mesenchymal functions. Although MCPIP1 expression increased in parallel with the increase in specific mesenchymal cell products, the MCPIP1 expression level was not consistent with the observed decrease in specific endothelial marker expression. Autophagy mediated the effects of MCPIP1, as rapamycin and 3-MA enhanced and attenuated the effect of SiO2 on HUVECs, respectively. MAPKs and the PI3K/Akt pathway were involved in the regulation of MCPIP1 by SiO2, and Pyk2 and MLC-2 mediated cell migration. CONCLUSION: Our findings reveal a new potential function of MCPIP1, suggesting a possible mechanism of fibrosis in pulmonary silicosis.

Neogambogic acid prevents silica-induced fibrosis via inhibition of high-mobility group box 1 and MCP-1-induced protein 1.

BACKGROUND: Silicosis is a systemic disease caused by inhaling silicon dioxide (SiO2); early stages are characterized by alveolar inflammation, and later stages are characterized by progressive lung fibrosis. Mounting evidence indicates that high-mobility group box 1 (HMGB1) is involved in pulmonary fibrosis. Whether neogambogic acid (NGA) inhibits macrophage and fibroblast activation induced by SiO2 by targeting HMGB1 remains unclear. METHODS AND RESULTS: Experiments using cultured mouse macrophages (RAW264.7 cells) demonstrated that SiO2 treatment induces the expression of HMGB1 in a time- and dose-dependent manner via mitogen-activated protein kinases (MAPKs) and the phosphatidylinositol 3-kinase (PI3K)/Akt pathway; in turn, this expression causes macrophage apoptosis and fibroblast activation. Pretreating macrophages with NGA inhibited the HMGB1 expression induced by SiO2 and attenuated both macrophage apoptosis and fibroblast activation. Moreover, NGA directly inhibited MCP-1-induced protein 1 (MCPIP1) expression, as well as markers of fibroblast activation and migration induced by SiO2. Furthermore, the effects of NGA on macrophages and fibroblasts were confirmed in vivo by exposing mice to SiO2. CONCLUSION: NGA can prevent SiO2-induced macrophage activation and apoptosis via HMGB1 inhibition and SiO2-induced fibrosis via the MCPIP1 pathway. Targeting HMGB1 and MCPIP1 with NGA could provide insights into the potential development of a therapeutic approach for alleviating the inflammation and fibrosis induced by SiO2.

Macrophage-derived MCPIP1 mediates silica-induced pulmonary fibrosis via autophagy.

BACKGROUND: Silicosis is characterized by accumulation of fibroblasts and excessive deposition of extracellular matrix. Monocyte chemotactic protein-1-induced protein 1 (MCPIP1) plays a critical role in fibrosis induced by SiO2. However, the details of the downstream events of MCPIP1 activity in pulmonary fibrosis remain unclear. To elucidate the role of MCPIP1-induced autophagy in SiO2-induced fibrosis, both the upstream molecular mechanisms and the functional effects of SiO2 on cell apoptosis, proliferation and migration were investigated. RESULTS: Experiments using primary cultures of alveolar macrophages from healthy donors and silicosis patients as well as differentiated U937 macrophages demonstrated the following results: 1) SiO2 induced macrophage autophagy in association with enhanced expression of MCPIP1; 2) autophagy promoted apoptosis and activation of macrophages exposed to SiO2, and these events induced the development of silicosis; 3) MCPIP1 facilitated macrophage apoptosis and activation via p53 signaling-mediated autophagy; and 4) SiO2-activated macrophages promoted the proliferation and migration of fibroblasts via the MCPIP1/p53-mediated autophagy pathway. CONCLUSIONS: Our results elucidated a link between SiO2-induced fibrosis and MCPIP1/p53 signaling-mediated autophagy. These findings provide novel insight into the potential targeting of MCPIP1 or autophagy in the development of potential therapeutic strategies for silicosis.

Unveiling potential adverse events associated with escitalopram oxalate: A real-world analysis based FDA adverse event reporting system database.

OBJECTIVE: The study aimed to conduct a multidimensional evaluation of potential adverse events (AEs) of escitalopram oxalate based on the FDA adverse event reporting system (FAERS) database. METHODS: This study utilized the reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and multi-item gamma-poisson shrinker (MGPS) to mine and analyze data from the FAERS database from the first quarter of 2004 to the second quarter of 2023. RESULTS: There was a total of 19,854 AE reports related to escitalopram oxalate, extracting 625 preferred terms (PTs), and covering 27 system organ classes (SOCs). The results showed that the number of reports by females was significantly higher than males, accounting for 57.68%. The reporting number was higher in 2018 and 2019, accounting for 9.50% and 10.18% of the total reports, respectively. The main reporters were consumers and other health professionals, accounting for 26.99% and 26.75% respectively. The majority of the reports were primarily from the United States. Newly emerging AE signals such as intentional overdose (n = 691, ROR 8.51, PRR 8.45, IC 3.05, Empirical Bayesian Geometric Mean (EBGM) 8.35), suicide attempt (n = 665, ROR 8.58, PRR 8.52, IC 3.06, EBGM 8.42), serum serotonin (n = 5, ROR 1044.78, PRR 1044.71, IC 2.56, EBGM 392.39), anti-actin antibody positive (n = 5, ROR 626.87, PRR 626.83, IC 2.56, EBGM 313.91), among others, were not mentioned in the drug's label. CONCLUSION: While escitalopram oxalate has clear benefits in the treatment of depression and other mental health disorders, the presence of AEs also suggests risks associated with its use. Particularly concerning are risks of suicide and changes in serum serotonin levels.

Which institutional investors can improve the level of corporate ESG information disclosure?

The inconsistency of existing findings on the relationship between institutional investors' shareholdings and the level of corporate Environmental, Social and Governance (ESG) disclosure may lie in the insufficient consideration of the heterogeneity of institutional investors and investee firms. In this paper, from the perspective of institutional investor heterogeneity, we use a two-way fixed effects model to examine the impact of institutional investors on corporate ESG disclosure and the possible mechanism of this impact using a sample of Chinese A-share-listed firms from 2012 to 2020. We show that institutional investor shareholding can improve the level of corporate ESG information disclosure by enhancing auditor supervision and analyst attention to these external supervision. In terms of institutional investor heterogeneity, it is found that independent institutional investors and stable institutional investors play a stronger role in promoting the level of ESG information disclosure. Moreover, the positive net effect of the institutional investors on improving the level of ESG information disclosure is more pronounced in non-heavily polluting industries and state-owned enterprises. This paper enriches the impact of institutional investors' shareholding on corporate ESG disclosure from a heterogeneity perspective.

CPU86017-RS attenuate hypoxia-induced testicular dysfunction in mice by normalizing androgen biosynthesis genes and pro-inflammatory cytokines.

AIM: Downregulation of androgen biosynthesis genes StAR (steroidogenic acute regulatory) and 3ß-HSD (3ß-hydroxysteroid dehydrogenase) contributes to low testosterone levels in hypoxic mice and is possibly related to increased expression of pro-inflammatory cytokines in the testis. The aim of this study is to investigate the effects of CPU86017-RS that block Ca(2+) influx on hypoxia-induced testis insult in mice. METHODS: Male ICR mice were divided into 5 groups: control group, hypoxia group, hypoxia group treated with nifedipine (10 mg/kg), hypoxia groups treated with CPU86017-RS (60 or 80 mg/kg). Hypoxia was induced by placing the mice in a chamber under 10%±0.5% O2 for 28 d (8 h per day). The mice were orally administered with drug in the last 14 d. At the end of experiment the testes of the mice were harvested. The mRNA and protein levels of StAR, 3ß-HSD, connexin 43 (Cx43), matrix metalloprotease 9 (MMP9), endothelin receptor A (ET(A)R) and leptin receptor (OBRb) were analyzed using RT-PCR and Western blotting, respectively. The malondialdehyde (MDA), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH) and acid phosphatase (ACP) levels were measured using biochemical kits. Serum testosterone concentration was measured with radioimmunoassay. RESULTS: Hypoxia significantly increased the MDA level, and decreased the LDH, ACP and SDH activities in testes. Meanwhile, hypoxia induced significant downregulation of StAR and 3ß-HSD in testes responsible for reduced testosterone biosynthesis. It decreased the expression of Cx43, and increased the expression of MMP9, ETAR and OBRb, leading to abnormal testis function and structure. These changes were effectively diminished by CPU86017-RS (80 mg/kg) or nifedipine (10 mg/kg). CONCLUSION: Low plasma testosterone level caused by hypoxia was due to downregulation of StAR and 3ß-HSD genes, in association with an increased expression of pro-inflammatory cytokines. These changes can be alleviated by CPU86017-RS or nifedipine.

Raisanberine protected pulmonary arterial rings and cardiac myocytes of rats against hypoxia injury by suppressing NADPH oxidase and calcium influx.

AIM: To investigate the protection of pulmonary arterial rings and cardiac myocytes of rats by raisanberine (RS), a derivative of berberine, against hypoxia injury and to elucidate the action mechanisms. METHODS: Adult SD rats were exposed to intermittent hypoxia for 17 d or 28 d. The pulmonary arterial rings were isolated and vascular activity was measured using a transducer and computer-aided system. The difference in the tension produced by phenylephrine in the presence and absence of L-nitroarginine (10 µmol/L) was referred to as the NO bioavailability; the maximum release of NO was assessed by the ratio of the maximal dilatation caused by ACh to those caused by sodium nitroprusside. After the lungs were fixed, the internal and the external diameters of the pulmonary arterioles were measured using a graphic analysis system. Cultured cardiac myocytes from neonatal rats were exposed to H(2)O(2) (10 µmol/L) to mimic hypoxia injury. ROS generation and [Ca(2+)](i) level in the myocytes were measured using DHE and Fluo-3 fluorescence, respectively. RESULTS: Oral administration of RS (80 mg/kg), the NADPH oxidase inhibitor apocynin (APO, 80 mg/kg) or Ca(2+) channel blocker nifedipine (Nif, 10 mg/kg,) significantly alleviated the abnormal increase in the vasoconstriction force and endothelium-related vasodilatation induced by the intermittent hypoxia. The intermittent hypoxia markedly decreased the NO bioavailability and maximal NO release from pulmonary arterial rings, which were reversed by APO or RS administration. However, RS administration did not affect the NO bioavailability and maximal NO release from pulmonary arterial rings of normal rats. RS, Nif or APO administration significantly attenuated the pulmonary arteriole remodeling. Treatment of cultured cardiac myocytes with RS (10 µmol/L) suppressed the ROS generation and [Ca(2+)](i) increase induced by H(2)O(2), which were comparable to those caused by APO (10 µmol/L) or Nif (0.1 µmol/L). CONCLUSION: Raisanberine relieved hypoxic/oxidant insults to the pulmonary artery and cardiac myocytes of rats by suppressing activated NADPH oxidase and increased calcium influx.

Erratum: circRNA Mediates Silica-Induced Macrophage Activation Via HECTD1/ZC3H12A-Dependent Ubiquitination: Erratum.

[This corrects the article DOI: 10.7150/thno.21648.].

GREM1/PPP2R3A expression in heterogeneous fibroblasts initiates pulmonary fibrosis.

BACKGROUND: Fibroblasts have important roles in the synthesis and remodeling of extracellular matrix (ECM) proteins during pulmonary fibrosis. However, the spatiotemporal distribution of heterogeneous fibroblasts during disease progression remains unknown. RESULTS: In the current study, silica was used to generate a mouse model of pathological changes in the lung, and single-cell sequencing, spatial transcriptome sequencing and an analysis of markers of cell subtypes were performed to identify fibroblast subtypes. A group of heterogeneous fibroblasts that play an important role at the early pathological stage were identified, characterized based on the expression of inflammatory and proliferation genes (termed inflammatory-proliferative fibroblasts) and found to be concentrated in the lesion area. The expression of GREM1/protein phosphatase 2 regulatory subunit B''alpha (PPP2R3A) in inflammatory-proliferative fibroblasts was found to initiate early pulmonary pathological changes by increasing the viability, proliferation and migration of cells. CONCLUSIONS: Inflammatory-proliferative fibroblasts play a key role in the early pathological changes that occur in silicosis, and during this process, GREM1 is the driving factor that targets PPP2R3A and initiates the inflammatory response, which is followed by irreversible fibrosis induced by SiO2. The GREM1/PPP2R3A pathway may be a potential target in the early treatment of silicosis.

Sildenafil and FDP-Sr attenuate diabetic cardiomyopathy by suppressing abnormal expression of myocardial CASQ2, FKBP12.6, and SERCA2a in rats.

AIM: To study whether calcium-modulating proteins CASQ2, FKBP12.6 and SERCA2a participate in diabetic cardiomyopathy, and whether the beneficial actions of testosterone, sildenafil or fructose diphosphate Sr (FDP-Sr) in the treatment of diabetic cardiomyopathy result from suppressing these molecules. METHODS: Fifty male Sprague-Dawley (SD) rats were divided into five groups. Except for the normal group (non-diabetic), the other four groups were injected with streptozotocin (STZ, 60 mg/kg, ip) to induce diabetes. Four weeks after STZ injection, the four groups received sildenafil (12 mg·kg(-1)·d(-1), ig, for 4 week), FDP-Sr (200 mg/kg, ig, for 4 week), testosterone propionate (4 mg·kg(-1)·d(-1), sc, for 4 week), or no treatment, respectively. RESULTS: In the diabetic rats, blood glucose, free fatty acids, triglycerides, total cholesterol, and low-density lipoprotein cholesterol (LDL-C) were significantly increased, while high-density lipoprotein cholesterol (HDL-C) was significantly reduced, as compared to the non-diabetic rats. Cardiac dysfunction and myocardial hypertrophy of the diabetic rats were associated with increased mRNA and protein expression of iNOS, OBRb, and PKCɛ, while expression of CASQ2, SERCA2a, and FKBP12.6 was significantly down-regulated. Sildenafil and FDP-Sr, but not testosterone, significantly attenuated the biomarker abnormalities, without changing the metabolic abnormalities. CONCLUSION: CASQ2, FKBP12.6 and SERCA2a were down-regulated in diabetic cardiomyopathy. Sildenafil and FDP-Sr, but not testosterone, attenuated the cardiac dysfunction in diabetic cardiomyopathy, without changing the metabolic abnormalities, which may results from inhibiting oxidative and inflammatory cytokines and improving calcium homeostasis.

Role of circular RNAs in visceral organ fibrosis.

Circular RNAs (circRNAs) are a novel class of noncoding RNAs produced during pre-mRNA splicing and are emerging as new members of the gene regulatory network. Unlike linear RNAs, circRNAs have a unique structure with a covalently closed loop formed from the ligation of exons, introns, or both. CircRNAs are widely expressed in various organisms in a species-, tissue-, developmental stage- and disease-specific manner; circRNAs have been demonstrated to play a vital role in the pathogenesis and progression of human diseases. Fibrosis is characterized by an abnormal excessive deposition of extracellular matrix (ECM) in the extracellular space and plays important roles in many different pathologies of various organs. CircRNAs function as master regulators of gene expression to "sponge" or sequester other genes and target gene expression, transcription, splicing, etc. Increasing evidence has revealed that circRNAs are tightly associated with fibrotic diseases in various organs, including the lungs, liver, heart and kidneys. Herein, we provide the current understanding of the molecular characteristics of circRNAs and summarize the findings from circRNA studies in which the functions and mechanisms of action of circRNAs in organ fibrosis were proposed.