Connective Tissue Growth Factor Research Articles

Intratracheal instillation of polyacrylic acid induced pulmonary fibrosis with elevated transforming growth factor-β1 and connective tissue growth factor

We investigated the intratracheal instillation of Polyacrylic acid (PAA) in rats to determine if it would cause pulmonary disorders, and to see what factors would be associated with the pathological changes. Male F344 rats were intratracheally instilled with low (0.2 mg/rat) and high (1.0 mg/rat) doses of PAA. They were sacrificed at 3 days, 1 week, 1 month, 3 months, and 6 months after PAA exposure to examine inflammatory and fibrotic changes in the lungs. There was a persistent increase in the neutrophil count, lactate dehydrogenase (LDH) levels, cytokine-induced neutrophil chemoattractant (CINC) values in bronchoalveolar lavage fluid (BALF), and heme oxygenase-1 (HO-1) in lung tissue. Transforming growth factor-beta 1 (TGF-β1), a fibrotic factor, showed a sustained increase in the BALF until 6 months after intratracheal instillation, and connective tissue growth factor (CTGF) in lung tissue was elevated at 3 days after exposure. Histopathological findings in the lung tissue showed persistent (more than one month) inflammation, fibrotic changes, and epithelial-mesenchymal transition (EMT) changes. There was also a strong correlation between TGF-β1 in the BALF and, especially, in the fibrosis score of histopathological specimens. Intratracheal instillation of PAA induced persistent neutrophilic inflammation, fibrosis, and EMT in the rats’ lungs, and TGF-β1 and CTGF appeared to be associated with the persistent fibrosis.

Paeoniflorin alleviates TGF-β2-mediated extracellular matrix remodeling and oxidative stress in human trabecular meshwork cells.

The multifunctional profibrotic cytokine transforming growth factor-beta2 (TGF-β2) is implicated in the pathophysiology of primary open angle glaucoma. Paeoniflorin (PAE) is a monoterpene glycoside with multiple pharmacological efficacies, such as antioxidant, anti-fibrotic, and anti-inflammatory properties. Studies have demonstrated that paeoniflorin protects human corneal epithelial cells, retinal pigment epithelial cells, and retinal microglia from damage. Here, the biological role of PAE in TGF-β2-dependent remodeling of the extracellular matrix (ECM) within the trabecular meshwork (TM) microenvironment. Primary or transformed (GTM3) human TM (HTM) cells conditioned in serum-free media were incubated with TGF-β2 (5ng/mL). PAE (300μM) was added to serum-starved confluent cultures of HTM cells for 2h, followed by incubation with TGF-β2 for 22h. SB-431542, a TGF-β receptor inhibitor (10μM), was used as a positive control. The levels of intracellular ROS were evaluated by CellROX green dye. Western blotting was used to measure the levels of TGF-β2/Smad2/3 signaling-related molecules. Collagen 1α1, collagen 4α1, and connective tissue growth factor (CTGF) expression was evaluated by RT-qPCR. Immunofluorescence assay was conducted to measure collagen I/IV expression in HTM cells. Phalloidin staining assay was conducted for evaluating F-actin stress fiber formation in the cells. PAE attenuated TGF-β2-induced oxidative stress and suppressed TGF-β2-induced Smad2/3 signaling in primary or transformed HTM cells. Additionally, PAE repressed TGF-β2-induced upregulation of collagen 1α1, collagen 4α1, and CTGF expression and reduced TGF-β2-mediated collagen I/IV expression and of F-actin stress fiber formation in primary or transformed HTM cells. PAE alleviates TGF-β2-induced ECM deposition and oxidative stress in HTM cells through inactivation of Smad2/3 signaling.

The intervention of curcumin on rodent models of hepatic fibrosis: A systematic review and meta-analysis.

This study aimed to evaluate the intervention effect of curcumin on hepatic fibrosis in rodent models through systematic review and meta-analysis, in order to provide meaningful guidance for clinical practice. A systematic retrieval of relevant studies on curcumin intervention in rats or mice hepatic fibrosis models was conducted, and the data were extracted. The outcome indicators included liver cell structure and function related indicators, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), albumin (ALB), ratio of albumin to globulin (A/G), total bilirubin (TBIL), bax protein, bcl-2 protein and index of liver, as well as the relevant indicators for evaluating the degree of hepatic fibrosis, such as hyaluronic acid (HA), laminin (LN), type I collagen (Collagen I), type III collagen (Collagen III), type III procollagen (PCIII), type III procollagen amino terminal peptide (PIIINP), type IV collagen (IV-C), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), α-Smooth muscle actin (α-SMA), hydroxyproline (HYP), platelet derived factor-BB (PDGF-BB), connective tissue growth factor (CTGF) and transforming growth factor-β1 (TGF-β1), and oxidative stress-related indicators, such as superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px). These results were then analyzed by meta-analysis. Studies were evaluated for methodological quality using the syrcle's bias risk tool. A total of 59 studies were included in the meta-analysis, and the results showed that curcumin can reduce the levels of ALT, AST, ALP, TBIL, bax protein, and index of liver in hepatic fibrosis models. It can also reduce HA, LN, Collagen I, Collagen III, PCIII, PIIINP, IV-C, TNF-α, α-SMA, HYP, PDGF-BB, CTGF, TGF-β1 and MDA, and increase the levels of ALB, A/G, SOD, and GSH-Px in the hepatic fibrosis models. However, the effects of curcumin on bcl-2 protein, IL-6 in hepatic fibrosis models and index of liver in mice were not statistically significant. The analysis results indicate that curcumin can reduce liver cell apoptosis by maintaining the stability of liver cell membrane, inhibit the activation and proliferation of hepatic stellate cells by reducing inflammatory response, and alleviate tissue peroxidation damage by clearing oxygen free radicals.

#2161 Phosphodiesterase V inhibitor attenuates the fibrotic gene expression of human renal fibroblast derived from IgA nephropathy: an in-vitro study

Abstract Background and Aims Renal fibrosis (RF) is the final common pathway that determines the progression of many glomerular disease including IgA nephropathy (IgAN). Till date there is no definite therapy available to retard RF. Being the key mediator of fibrosis, TGF-β is being targeted in many studies. Phosphodiesterase V inhibitor (PDE5i) is known to inhibit TGF-β but its role in RF is yet to be established. Hence, in the current in-vitro study we wish to establish the role of PDE5 inhibitor as an inhibitor of TGF-β and hence the RF. Method This is a pilot study to evaluate the efficacy of ‘Phosphodiesterase V inhibitor’ on TGFβ1 induced fibrosis on fibroblasts derived from biopsy specimen of IgA nephropathy patients. Renal fibroblasts were cultured from six IgA patients. The fibroblasts cells were treated with PDE5i inhibitor (tadalafil) (at different doses of 1 µm, 5 µm, 10 µm and 15 µm), both before and after stimulation with transforming growth factor beta-1 (TGF-b1) (at doses of 5 ng/ml, 10 ng/ml, 15 ng/ml and 20 ng/ml). Gene expression was studied by real-time polymerase chain reaction (RT-PCR) for messenger ribonucleic acid (mRNA) of pro-fibrotic genes Col1a1, Col1a2, FN1, CTGF, ASMA, TIMP1, and anti-fibrotic MMP2. Objectives Results Our results shows that TGFβ significantly increased the expression of profibrotic gene (Col1a1, Col1a2, ASMA, CTGF, FN and TIMP1) at concentration of 10 ng/ml in the fibroblast cells derived from IgAN patients. Treatment of fibroblast cells with Tadalafil (PDE5 inhibitor) significantly decreased the pro-fibrotic gene mRNA expression (Col1a1, Col1a2, ASMA, CTGF, FN and TIMP1) with increased anti-fibrotic gene expression (MMP2) at the dose of 5 µm and 10 µm concentration in the fibroblast cells (Fig. 1). Conclusion This study may provide potential therapeutic target for prevention of renal fibrosis in IgAN patients. Till date PDE5 inhibitors were not used for IgAN. We found that, PDE5 inhibitor reduces the fibrosis in this in vitro study, this drug may be proposed as a potential therapy for IgAN.

#2985 Gut microbiome-dependent systemic alterations in experimental chronic kidney disease

Abstract Background and Aims Patients diagnosed with Chronic Kidney Disease (CKD) undergo a notable decline in both quality of life and life expectancy, primarily attributable to the heightened prevalence of cardiovascular diseases (CVD). These conditions not only contribute to the initiation of CKD but are also a consequence of inflammation associated with CKD. Despite optimal kidney replacement therapies, irreversible alterations of the CV system may persist. The responsible mechanisms in CKD leading to CVD are incompletely understood. CKD is characterized by gut microbial dysbiosis, with a significant proportion of uremic toxins suspected to have microbial origin. We hypothesize that the gut microbiota promotes inflammation and CV risk in states of impaired kidney function. Method Experimental CKD was induced in 129sv mice by 5/6 nephrectomy. Prior to nephrectomy, mice were assigned to receive either glucose (Ctrl) or a non-absorptive antibiotic cocktail (comprising Ampicillin, Metronidazole, Neomycin, and Vancomycin, Abx) via the drinking water to deplete their microbiomes throughout the 13-week study period. Ctrl and Abx-treated Sham-operated mice served as controls. Plasma, feces, and urine specimens were systematically collected at diverse time intervals, facilitating the longitudinal exploration of metabolite dynamics and CKD progression through an untargeted Nuclear Magnetic Resonance (NMR) approach. Simultaneously, echocardiography assessments were conducted at identical time points to assess cardiac function. Results Abx-treated CKD mice displayed improved kidney function, demonstrated by significantly reduced levels of plasma Cystatin C (0.2913 ± 0.1850 mg/L) compared to Ctrl (0.9133 ± 0.6616 mg/L)(p = 0.0256). Hearts from Abx-treated CKD mice exhibited significantly less remodeling, independent of their blood pressure (radiotelemetry measurements). The ratio of left ventricular (LV) mass to tibia length was 4.858 ± 0.3453 in the Abx-treated group compared to Ctrl (8.198 ± 0.3542) (p < 0.0001). Sirius red stained hearts revealed significantly less fibrosis in Abx-treated CKD mice (5.784 ± 5.465%) compared to Ctrl (11.98 ± 3.741%) (p = 0.0218). The cardiac expression of several damage-associated genes (Npbb, Ctgf, and Ngal) portrayed the same trend. To elucidate the interplay between the microbiome and the immune system underlying these observed effects, we provide a comprehensive atlas of the immune landscape in different organs (blood, spleen, heart, intestine), along with a catalogue of gut-derived metabolites, shedding light on the systemic alterations induced by microbiome-dependent mechanisms in CKD. Conclusion Our findings suggest that microbiome-dependent mechanisms drive kidney function decline and cardiac remodeling in experimental CKD. These results underscore the interplay between microbial alterations, metabolite dynamics, immune response, and cardiovascular complications in the context of CKD.

Effect of antibody-mediated connective tissue growth factor neutralization on lung edema in ventilator-induced lung injury in rats.

Acute respiratory distress syndrome (ARDS) is characterized by alveolar edema that can progress to septal fibrosis. Mechanical ventilation can augment lung injury, termed ventilator-induced lung injury (VILI). Connective tissue growth factor (CTGF), a mediator of fibrosis, is increased in ARDS patients. Blocking CTGF inhibits fibrosis and possibly vascular leakage. This study investigated whether neutralizing CTGF reduces pulmonary edema in VILI. Following LPS administration, rats were mechanically ventilated for 6h with low (6mL/kg; low VT) or moderate (10mL/kg; mod VT) tidal volume and treated with a neutralizing CTGF antibody (FG-3154) or placebo lgG (vehicle). Control rats without LPS were ventilated for 6h with low VT. Lung wet-to-dry weight ratio, FITC-labeled dextran permeability, histopathology, and soluble RAGE were determined. VILI was characterized by reduced PaO2/FiO2 ratio (low VT: 540 [381-661] vs. control: 693 [620-754], p < 0.05), increased wet-to-dry weight ratio (low VT: 4.8 [4.6-4.9] vs. control: 4.5 [4.4-4.6], p < 0.05), pneumonia (low VT: 30 [0-58] vs. control: 0 [0-0]%, p < 0.05) and interstitial inflammation (low VT: 2 [1-3] vs. control: 1 [0-1], p < 0.05). FG-3154 did not affect wet-to-dry weight ratio (mod VT + FG-3154: 4.8 [4.7-5.0] vs. mod VT + vehicle: 4.8 [4.8-5.0], p > 0.99), extravasated dextrans (mod VT + FG-3154: 0.06 [0.04-0.09] vs. mod VT + vehicle: 0.04 [0.03-0.09] µg/mg tissue, p > 0.99), sRAGE (mod VT + FG-3154: 1865 [1628-2252] vs. mod VT + vehicle: 1885 [1695-2159] pg/mL, p > 0.99) or histopathology. 'Double hit' VILI was characterized by inflammation, impaired oxygenation, pulmonary edema and histopathological lung injury. Blocking CTGF does not improve oxygenation nor reduce pulmonary edema in rats with VILI.

Exposure to microcystin-LR promotes astrocyte proliferation both in vitro and in vivo via Hippo signaling pathway

Microcystins (MCs) are toxic to the central nervous system of mammals. However, the direct toxicity of MCs on mammalian brain cells and the involved molecular mechanisms are not fully elucidated. Here, we incubated primary astrocytes, the major glial cell-type in the brain, with 0–12.5 μM concentrations of MC-LR for 48 h, and the impairment was evaluated. We found that MC-LR caused significant increases in the cell viability at the range of 0.05–1 μM concentrations with the highest density at 0.1 μM concentration. Treatment with 0.1 μM MC-LR induced YAP nuclear translocation and decreased the ratio of p-YAP to YAP. It also decreased mRNA levels of the upstream regulator (AMOT), and enhanced expressions of YAP interacted genes (Egfr, Tead1, and Ctgf) in primary astrocytes. Overexpression of AMOT significantly attenuated the increase of MC-LR-induced astrocyte proliferation and the expression of YAP downstream genes. These results indicate that Hippo signaling contributed to MC-LR-caused astrocyte proliferation. Further, reactive astrogliosis was observed in the mice brain after MC-LR exposure to environmentally relevant concentrations (20 or 100 μg/L) through drinking water for 16 weeks. Pathological observations revealed that 100 μg/L MC-LR exposure caused neuronal damages with characteristics of shrunken or vacuolation in the region of the cerebral cortex, striatum and cerebellum. These results were accompanied with increased oxidative stress and inflammatory response. Our data reveal the potential astrocytic mechanisms in MC-induced neurotoxicity and raise an alarm for neurodegenerative disease risk following daily exposure to MC-LR.

Pamrevlumab for Idiopathic Pulmonary Fibrosis

Current treatments for idiopathic pulmonary fibrosis slow the rate of lung function decline, but may be associated with adverse events that affect medication adherence. In phase 2 trials, pamrevlumab (a fully human monoclonal antibody that binds to and inhibits connective tissue growth factor activity) attenuated the progression of idiopathic pulmonary fibrosis without substantial adverse events. To assess the efficacy and safety of pamrevlumab for patients with idiopathic pulmonary fibrosis. Phase 3 randomized clinical trial including 356 patients aged 40 to 85 years with idiopathic pulmonary fibrosis who were not receiving antifibrotic treatment with nintedanib or pirfenidone at enrollment. Patients were recruited from 117 sites in 9 countries between July 18, 2019, and July 29, 2022; the last follow-up encounter occurred on August 28, 2023. Pamrevlumab (30 mg/kg administered intravenously every 3 weeks; n = 181) or placebo (n = 175) for 48 weeks. The primary outcome was absolute change in forced vital capacity (FVC) from baseline to week 48. There were 5 secondary outcomes (including time to disease progression, which was defined as a decline of ≥10% in predicted FVC or death). The exploratory outcomes included patient-reported symptoms. Adverse events were reported. Among 356 patients (mean age, 70.5 years; 258 [72.5%] were men; 221 [62.1%] were White), 277 (77.8%) completed the trial. There was no significant between-group difference for absolute change in FVC from baseline to week 48 (least-squares mean, -260 mL [95% CI, -350 to -170 mL] in the pamrevlumab group vs -330 mL [95% CI, -430 to -230 mL] in the placebo group; mean between-group difference, 70 mL [95% CI, -60 to 190 mL], P = .29). There were no significant between-group differences in any of the secondary outcomes or in the patient-reported outcomes. In the pamrevlumab group, there were 160 patients (88.4%) with treatment-related adverse events and 51 patients (28.2%) with serious adverse events vs 151 (86.3%) and 60 (34.3%), respectively, in the placebo group. During the study, 23 patients died in each group (12.7% in the pamrevlumab group vs 13.1% in the placebo group). Among patients with idiopathic pulmonary fibrosis treated with pamrevlumab or placebo, there was no statistically significant between-group difference for the primary outcome of absolute change in FVC from baseline to week 48. ClinicalTrials.gov Identifier: NCT03955146.

Development of alginate and alginate sulfate/polycaprolactone nanoparticles for growth factor delivery in wound healing therapy

Connective tissue growth factor (CTGF) holds great promise for enhancing the wound healing process; however, its clinical application is hindered by its low stability and the challenge of maintaining its effective concentration at the wound site. Herein, we developed novel double-emulsion alginate (Alg) and heparin-mimetic alginate sulfate (AlgSulf)/polycaprolactone (PCL) nanoparticles (NPs) for controlled CTGF delivery to promote accelerated wound healing. The NPs’ physicochemical properties, cytocompatibility, and wound healing activity were assessed on immortalized human keratinocytes (HaCaT), primary human dermal fibroblasts (HDF), and a murine cutaneous wound model. The synthesized NPs had a minimum hydrodynamic size of 200.25 nm. Treatment of HaCaT and HDF cells with Alg and AlgSulf2.0/PCL NPs did not show any toxicity when used at concentrations <50 µg/mL for up to 72 h. Moreover, the NPs’ size was not affected by elevated temperatures, acidic pH, or the presence of a protein-rich medium. The NPs have slow lysozyme-mediated degradation implying that they have an extended tissue retention time. Furthermore, we found that treatment of HaCaT and HDF cells with CTGF-loaded Alg and AlgSulf2.0/PCL NPs, respectively, induced rapid cell migration (76.12% and 79.49%, P<0.05). Finally, in vivo studies showed that CTGF-loaded Alg and AlgSulf2.0/PCL NPs result in the fastest and highest wound closure at the early and late stages of wound healing, respectively (36.49%, P<0.001 on day 1; 90.45%, P<0.05 on day 10), outperforming free CTGF. Double-emulsion NPs based on Alg or AlgSulf represent a viable strategy for delivering heparin-binding GF and other therapeutics, potentially aiding various disease treatments.

The natural history of CVB3 myocarditis in C57BL/6J mice: an extended in-depth characterization

Background and aimsViral infections are the leading cause of myocarditis. Besides acute cardiac complications, late-stage sequelae such as myocardial fibrosis may develop, importantly impacting the prognosis. Coxsackievirus B3 (CVB)-induced myocarditis in mice is the most commonly used translational model to study viral myocarditis and has provided the majority of our current understanding of the disease pathophysiology. Nevertheless, the late stages of disease, encompassing fibrogenesis and arrhythmogenesis, have been underappreciated in viral myocarditis research to date. The present study investigated the natural history of CVB-induced myocarditis in C57BL/6J mice, expanding the focus beyond the acute phase of disease. In addition, we studied the impact of sex and inoculation dose on the disease course. Methods and resultsC57BL/6J mice (12 weeks old; n=154) received a single intraperitoneal injection with CVB to induce viral myocarditis, or vehicle (PBS) as control. Male mice (n=92) were injected with 5 × 105 (regular dose) (RD) or 5 × 106 (high dose) (HD) plaque-forming units of CVB, whereas female mice received the RD only. Animals were sacrificed 1, 2, 4, 8, and 11 weeks after CVB or PBS injection. Virally inoculated mice developed viral disease with a temporary decline in general condition and weight loss, which was less pronounced in female animals (P<.001). In male CVB mice, premature mortality occurred between days 8 and 23 after inoculation (RD: 21%, HD: 20%), whereas all female animals survived. Over the course of disease, cardiac inflammation progressively subsided, with faster resolution in female mice. There were no substantial group differences in the composition of the inflammatory cell infiltrates: predominance of cytotoxic T cells at day 7 and 14, and a switch from arginase1-reactive macrophages to iNOS-reactive macrophages from day 7 to 14 were the main findings. There was concomitant development and maturation of different patterns of myocardial fibrosis, with enhanced fibrogenesis in male mice. Virus was almost completely cleared from the heart by day 14. Serum biomarkers of cardiac damage and cardiac expression of remodeling genes were temporarily elevated during the acute phase of disease. Cardiac CTGF gene upregulation was less prolonged in female CVB animals. In vivo electrophysiology studies at weeks 8 and 11 demonstrated that under baseline conditions (i.e. in the absence of proarrhythmogenic drugs), ventricular arrhythmias could only be induced in CVB animals. The cumulative arrhythmia burden throughout the entire stimulation protocol was not significantly different between CVB and control groups. ConclusionCVB inoculation in C57BL/6J mice represents a model of acute self-limiting viral myocarditis, with progression to different patterns of myocardial fibrosis. Sex, but not inoculation dose, seems to modulate the course of disease.

Blocking the MIR155HG/miR-155 axis reduces CTGF-induced inflammatory cytokine production and α-SMA expression via upregulating AZGP1 in hypertrophic scar fibroblasts

Hypertrophic scarring (HS) is a pathological condition characterized by excessive fibrosis and inflammation, resulting in excessive extracellular matrix formation in the skin. MIR155HG, a long non-coding RNA, is abnormally upregulated in fibrotic tissues; however, its underlying mechanism is poorly understood. Using single-cell sequencing data, we analyzed connective tissue growth factor (CTGF) expression in various cell types in HS and normal skin tissues and MIR155HG expression in clinical samples. To investigate the mechanism of fibrosis, an in vitro model using CTGF-treated hypertrophic scar fibroblasts (HSFBs) was established and qRT-PCR, western blotting and ELISA assays were performed to investigate the expression of interleukin (IL)-1β, IL-6, and mesenchymal markers α-smooth muscle actin (α-SMA). CTGF stimulates MIR155HG level through phosphorylated STAT3 binding to the MIR155HG promoter. We analyzed the methylation of MIR155HG, assessed the levels of miR-155-5p/−3p in CTGF-treated HSFBs and identified differentially expressed genes among HS and NS samples using the Gene Expression Omnibus RNA sequencing data. The binding between miR-155-5p/−3p and AZGP1 was confirmed using a dual-luciferase assay and inflammatory cytokine production and α-SMA expression were investigated in rescue experiments. The findings revealed that CTGF elevated inflammatory cytokine production, α-SMA and MIR155HG expression in HSFBs. MIR155HG is upregulated in HS tissues due to low DNA methylation. Mechanistically, miR-155-5p/−3p was directly bound to MIR155HG 3’UTR. MIR155HG silencing inhibited cytokine production and α-SMA expression by repressing the generation of miR-155-5p/−3p in CTGF-treated HSFBs. Bioinformatics analysis and luciferase reporter assays revealed that miR-155-5p/−3p targets AZGP1. In addition, transfection with plasmids carrying AZGP1 cDNA significantly inhibited the signaling activity of miR-155-5p/−3 p-overexpressing HSFBs. Our findings highlight the importance of the MIR155HG/miR-155/AZGP1 axis in regulating cytokine production and α-SMA in HS.

Linagliptin ameliorates tacrolimus-induced renal injury: role of Nrf2/HO-1 and HIF-1α/CTGF/PAI-1

BackgroundTacrolimus (TAC) is a frequently used immunosuppressive medication in organ transplantation. However, its nephrotoxic impact limits its long-term usage. This study aims to investigate the effect of linagliptin (Lina) on TAC-induced renal injury and its underlying mechanisms.Methods and resultsThirty-two Sprague Dawley rats were treated with TAC (1.5 mg/kg/day, subcutaneously) and/or Lina (5 mg/kg/day, orally) for 4 weeks. Histological examination was conducted, and serum and urinary biomarkers were measured to assess kidney function and integrity. Furthermore, ELISA, Western blot analysis and immunohistochemical assay were employed to determine signaling molecules of oxidative stress, profibrogenic, hypoxic, and apoptotic proteins. Tacrolimus caused renal dysfunction and histological deterioration evidenced by increased serum creatinine, blood urea nitrogen (BUN), urinary cystatin C, and decreased serum albumin as well as elevated tubular injury and interstitial fibrosis scores. Additionally, TAC significantly increased the expression of collagen type-1, alpha-smooth muscle actin (α-SMA), plasminogen activator inhibitor-1 (PAI-1), and transforming growth factor-beta1 (TGF-β1) renal content. Moreover, TAC decreased the expression of nuclear factor erythroid-2-related factor2 (Nrf2), heme oxygenase 1 (HO-1), and mitochondrial superoxide dismutase (SOD2). In addition, TAC increased protein expression of hypoxia-inducible factor1-alpha (HIF-1α), connective tissue growth factor (CTGF), inducible nitric oxide synthase (iNOS), 8-hydroxy-2-deoxyguanosine (8-OHdG), as well as nitric oxide (NO), 4-hydroxynonenal, caspase-3 and Bax renal contents. Furthermore, TAC decreased Bcl-2 renal contents. The Lina administration markedly attenuated these alterations.ConclusionLina ameliorated TAC-induced kidney injury through modulation of oxidative stress, hypoxia, and apoptosis related proteins.

Lipid nephrotoxicity mediated by HIF-1α activation accelerates tubular injury in diabetic nephropathy

This study is intended to explore the effect of hypoxia-inducible factor-1α (HIF-1α) activation on lipid accumulation in the diabetic kidney. A type 1 diabetic rat model was established by STZ intraperitoneal injection. Cobalt chloride (CoCl2) and YC-1 were used as the HIF-1α activator and antagonist, respectively. CoCl2 treatment significantly increased HIF-1α expression, accelerated lipid deposition, and accelerated tubular injury in diabetic kidneys. In vitro, CoCl2 effectively stabilized HIF-1α and increased its transportation from the cytoplasm to the nucleus, which was accompanied by significantly increased lipid accumulation in HK-2 cells. Furthermore, results obtained in vivo showed that HIF-1α protein expression in the renal tubules of diabetic rats was significantly downregulated by YC-1 treatment. Meanwhile, lipid accumulation in the tubules of the DM + YC-1 group was markedly decreased in comparison to the DM + DMSO group. Accordingly, PAS staining revealed that the pathological injury caused to the tubular epithelial cells was alleviated by YC-1 treatment. Furthermore, the blood glucose level, urine albumin creatinine ratio, and NAG creatinine ratio in the DM + YC-1 group were significantly decreased compared to the DM + DMSO group. Moreover, the protein expression levels of transforming growth factor β1 (TGF-β1) and connective tissue growth factor (CTGF) in diabetic kidneys were decreased by YC-1 treatment. Our findings demonstrate that the activation of HIF-1α contributed to interstitial injury in a rat model of diabetic nephropathy and that the underlying mechanism involved the induction of lipid accumulation.

التنبؤ المبكر بالاعتلال الكلوي لمرضى عراقين مصابين بالسكري النوع الثاني بدلالة تقييم بعض العوامل البيوكيمائية ذات الصلة

داء السكري من النوع 2 (T2DM) هو مرض معقد يصيب العديد من الأعضاء إلى جانب البنكرياس مثل الكلى والكبد والدماغ والعين. بسبب ارتفاع السكر في الدم لفترات طويلة وعدم السيطرة على مرض السكري مع وجود عوامل خطر أخرى ، يمكن أن تحدث مضاعفات مرض السكري. تشمل مضاعفات مرض السكري مضاعفات الأوعية الدموية الدقيقة والأوعية الدموية الكبيرة التي تستهدف الكلى. تهدف الدراسة الحالية إلى التحقق من مستوى الانجوتينسن المحول للانزيم ACE-2)) ، عامل نمو النسيج الضام (CTGF) جنبًا إلى جنب مع بعض العوامل البيوكيميائية ذات الصلة في النساء المصابات بداء السكري واعتلال الكلية السكري مقارنة بالضوابط الصحية. اشتملت الدراسة على 90 مريض تتراوح أعمارهم بين 30-65 سنة. يعانون من مرض السكري من النوع 2 مقسمون إلى ثلاث مجاميع على أساس معايير ACR تشمل البيلة الألبومينية الطبيعية ، البيلة الألبومينية الدقيقة ، البيلة الألبومينية الكبيرة 30 مريضًا لكل مجموعة و 30 شخصًا يتمتعون بصحة جيدة كانوا بمثابة المجموعة الضابطة ، منمن زاروا مستشفى بغداد التعليمي / المدينة الطبية و مستشفى اليرموك التعليمي ، في الفترة ما بين ديسمبر 2021 ومايو 2022. تم تحديد مستوياتACE-2 و CTGF باستخدام تقنية ELISA. أظهرت النتائج وجود فروق ذات دلالة إحصائية بين مجموعات المرضى والمجموعة الضابطة لعامل CTGF ، ووجد أن مستويات ACE-2 تزيد بشكل كبير في مجموعات المرضى عن مجموعة التحكم الصحية. كما أظهرت النتائج أن كلا من سكر الدم الصائم FBS و هيموكلوبينA1C (HbA1C)قد زاد بشكل ملحوظ في مجموعات المرضى مقارنة بالمجموعة الصحية. علاوة على ذلك ، كشفت قيم معدل الترشيح الكبيبي المقدر( ( eGFR عن فروق ذات دلالة إحصائية بين جميع المجموعات المدروسة ، وكذلك اظهرت نتائج ACR وجود فروقات ذات دلالة إحصائية بين مجموعات المرضى الثلاثة ، والتي تمثل المعايير الأساسية لتصنيف مجموعات المرضى. على أساس النتائج التي تم الحصول عليها في هذه الدراسة ، يمكن استنتاج ان عاملي ACE-2 و CTGF يمكن تطبيقهما كواسمات تنبؤية مبكرة موثوقة للكشف عن المرض.

Drugs targeting CTGF in the treatment of pulmonary fibrosis.

Pulmonary fibrosis represents the final alteration seen in a wide variety of lung disorders characterized by increased fibroblast activity and the accumulation of substantial amounts of extracellular matrix, along with inflammatory damage and the breakdown of tissue architecture. This condition is marked by a significant mortality rate and a lack of effective treatments. The depositing of an excessive quantity of extracellular matrix protein follows the damage to lung capillaries and alveolar epithelial cells, leading to pulmonary fibrosis and irreversible damage to lung function. It has been proposed that the connective tissue growth factor (CTGF) plays a critical role in the advancement of pulmonary fibrosis by enhancing the accumulation of the extracellular matrix and exacerbating fibrosis. In this context, the significance of CTGF in pulmonary fibrosis is examined, and a summary of the development of drugs targeting CTGF for the treatment of pulmonary fibrosis is provided.

Neuromuscular Junction Remodeling: the Role of Sub-Synaptic Nuclei, Terminal Schwann Cells, and Trophic Signaling Following Neuromusculoskeletal Injuries

Peripheral nerve crush injury is a well-established model of neuromuscular junction (NMJ) denervation and subsequent re-innervation. Functionally, the muscle tissue follows a similar pattern as neural recovery, with immediate loss of force production that steadily improves in parallel with rates of re-innervation. On the other hand, traumatic injury to the muscle tissue itself, specifically volumetric muscle loss (VML), results in an irrecoverable loss of muscle function. Recent work has indicated significant impairments to the NMJ following VML that appear chronic in nature, alongside functional recovery. Thus, the goal of this study was to compare the effects of nerve and muscle injury on NMJ remodeling, with the hypothesis that VML will result in chronic alterations to the NMJ, including a higher degree of cellular localization to the NMJ. Even numbers of adult male and female mice were used with three experimental groups: injury naive, nerve crush, and VML-injury; and three terminal timepoints: 3-, 48-, and 112-days post injury. Data were analyzed by three-way ANOVA with Tukey’s HSD post-hoc. Confirming the assumed recoverability of the two injury models, we found in vivo maximal torque was fully restored following nerve crush injury (Tukey’s HSD post hoc p=0.730), but remained at a significant deficit following VML (~41% lower than injury naïve; Tukey’s HSD post hoc p&lt;0.001). Compared to nerve crush and injury naïve, we found VML results in aberrantly high trophic signaling and numbers of supporting cells. Protein expression of neuregulin-1 and connective tissue growth factor were both highest in the VML group (~1.2-fold and 12-fold increase compared to injury naïve, respectively; Main effect of group, p&lt;0.001). While nerve crush injury elicited a transient increase in terminal Schwann cell numbers (~38% higher than injury naïve at 48dpi; Tukey’s HSD post hoc p&lt;0.001), VML resulted in a chronic increase (~53% and 27% higher than injury naïve at 48 and 112dpi, respectively; Tukey’s HSD post hoc p&lt;0.001). Moreover, nerve crush injury did not alter the number of sub-synaptic nuclei per NMJ, while VML resulted in significant increases at both 48- and 112-days post injury (~27% and 24% higher than injury naïve, respectively; Tukey’s HSD post hoc p=0.002). In some cases, sex differences were detected, including higher rates of innervation in females than males (Main effect of sex p=0.003), particularly following VML-injury (Tukey’s HSD post hoc p=0.004). The findings herein bear a striking resemblance to NMJs found in dystrophic muscle, which are thought to be the result of continuous cycles of muscle fiber degeneration and regeneration. Thus, the NMJ changes observed following VML may be indicative of a larger issue, such as chronic muscle fiber remodeling and pervasive fibrotic accumulation. R01-AR078903 (JAC &amp; SMG); K02-AG081488 (SMG). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Cardiomyocyte Specific MLK3 Deletion Opposes LV Dysfunction and Cardiac Fetal Gene Re-Expression

Study Objective: To determine the cardiac myocyte (CM) and blood pressure-independent effects of Mixed lineage kinase 3 (MLK3) in the regulation of left ventricular (LV) function at baseline and in response to pathological stress. Background: MLK3 functions as a direct substrate effector of cGMP-dependent protein kinase 1α (PKG1α). Whole-body MLK3 deletion in mice increases cardiac dysfunction and remodeling after pressure overload and prevents the therapeutic effect of cGMP augmentation on LV function. However, MLK3 deletion also causes hypertension, which may confound these findings. Hypothesis: MLK3 opposes LV dysfunction through a blood pressure-independent function in the cardiac myocyte (CM). Methods: We generated mice harboring LoxP sites flanking the MAP3K11 gene encoding MLK3 (MLK3fl/fl) and crossed them with αMHC-Cre transgenic mice, enabling constitutive postnatal cardiac myocyte-specific MLK3 deletion (CMKO). Male and female 3- and 6-month-old MLK3 CMKO and control MLK3 intact (MLK3fl/fl Cre-) littermates were studied in the basal state. We also performed transaortic constriction (TAC) or sham surgery for 4 weeks on 3-month-old male mice. We assessed LV structure and function by organ mass, echocardiography, pressure volume loop analysis, qPCR, and immunoblot. In basal and TAC studies, we used age-matched αMHC-Cre x MLK3+/+ (non-floxed) mice as additional controls. Results: MLK3 gene excision in CMs was confirmed by PCR. By 6 months of age, MLK3 CMKO mice displayed: progressive reduction in LV ejection fraction; increase in LV internal diameter; and LV hypertrophy, indicating LV dysfunction and pathological remodeling, compared with littermate controls or with αMHC-Cre x MLK3+/+ non-floxed mice. This effect was more prominent in females than in males. LV fetal gene expression did not differ between genotypes at 3 months. At 6 months of age, however, the fetal genes nppa, RCAN, and CTGF were significantly upregulated in both male and female MLK3 CMKO mice, compared with MLK3 intact, indicating pathological remodeling. After 4-week TAC, MLK3 CMKO LVs developed more severe reduction in LV systolic function compared with MLK3 intact littermates as assayed by echocardiographic measures of LV ejection fraction; and invasive hemodynamic indices of preload recruitable stroke work, maximum LV pressure and LV developed pressure. The MLK3 CMKO LVs also demonstrated a more eccentric remodeling phenotype in which LV mass/tibia length, LV end diastolic and end systolic diameters increased more severely in CMKO mice, with corresponding reduced LV wall thicknesses. Finally, lung mass/tibia length was elevated in the MLK3 CMKO TAC mice compared to MLK3 intact TAC littermates, indicating overt heart failure. Conclusion: (1) MLK3 functions as a tonic inhibitor of LV dysfunction and pathological remodeling through a role in the CM, possibly through sex-specific mechanisms. (2) Intact MLK3 is required for normal LV compensation and concentric remodeling in response to pressure overload. These findings have important clinical implications, as drugs which activate PKG1 in heart failure improve outcomes but are limited by excess hypotension. As a myocardial PKG1 substrate which opposes pathological LV remodeling through blood pressure-independent mechanisms, MLK3 may represent a candidate therapeutic target for heart failure. NIH 1R01HL162919. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Establishment of Anoxia/cytokine-induced Injury and Regeneration in Colonoids

Intestinal epithelial cells (IECs) play key roles in nutrient absorption and fluid secretion, providing a barrier to protect cells. IECs, derived from intestinal stem cells (ISCs), are crucial in maintaining intestinal homeostasis and regeneration, which is crucial in gastrointestinal diseases such as inflammatory bowel disease (IBD). To study epithelial injury/regeneration, primary cultured colonoids were utilized as a model system to mimic injury. They retain the composition and differentiation of the tissue, making it a suitable model for studying homeostasis and regeneration of ISCs in vitro. Anoxia and proinflammatory cytokines frequently coexist and exacerbate one another during intestinal injury. However, anoxic conditions have been mainly ignored in previous research. Thus, we developed a regeneration model using cytokines/anoxia injury to better recapitulate intestinal inflammation. Colonoids were treated with cytokines TNF-α and IFN-γ (5 ng/μL) in anoxic conditions for 24 hours to provoke an injury. After 24 hours of injury, the colonoids were exposed to normal oxygen and media conditions for regeneration. Regeneration was observed for 24, 48, and 72 hours and documented using photomicrographs. Morphological analysis detailed that injury was most severe 24 hours post-injury with the combined induction of cytokines and anoxia resulting in decreased colonoid area and number of buds compared to control groups. RT-PCR analysis detailed mRNA expression of stem cell markers ( Lgr5, Bmi1, and Hopx), Wnt ( Axin2, Myc2, and Ascl2), and YAP target genes ( Sca1 and Ctgf) were increased at peak injury and returned to pre-injury levels at 72 hours of recovery. Regeneration of the colonoids is consistent with in vivo observations, thus confirming the validity of the model. This versatile model can be used to study responses to injury and regeneration of intestinal epithelium and the function of ISCs with applications in intestinal disease therapeutics. University of Maryland College of Agriculture and Natural Resources and the Maryland Agricultural Experiment Station Undergraduate Research Grant Grant #4307572 from the Maryland Stem Cell Research Fund. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Neutralization of CX3CL1 Attenuates TGF-β-Induced Fibroblast Differentiation Through NF-κB Activation and Mitochondrial Dysfunction in Airway Fibrosis.

Severe asthma, characterized by inflammation and airway remodeling, involves fibroblast differentiation into myofibroblasts expressing α-SMA. This process leads to the production of fibronectin and connective tissue growth factor (CTGF), driven by factors such as transforming growth factor (TGF)-β. Furthermore, the persistent presence of myofibroblasts is associated with resistance to apoptosis and mitochondrial dysfunction. The chemokine (C-X3-C motif) ligand 1 (CX3CL1) plays a role in tissue fibrosis. However, it is currently unknown whether neutralization of CX3CL1 decreases TGF-β-induced fibroblast differentiation and mitochondrial dysfunction in normal human lung fibroblasts (NHLFs). CX3CL1/C-X3-C motif chemokine receptor 1 (CX3CR1), CX3CL1 was analyzed by immunofluorescence (IF) or immunohistochemical (IHC) staining of ovalbumin-challenged mice. CX3CL1 release was detected by ELISA. TGF-β-induced CTGF, fibronectin, and α-SMA expression were evaluated in NHLFs following neutralization of CX3CL1 (TP213) treatment for the indicated times by Western blotting or IF staining. Mitochondrion function was detected by a JC-1 assay and seahorse assay. Cell apoptosis was observed by a terminal uridine nick-end labeling (TUNEL) assay. An increase in CX3CL1 expression was observed in lung tissues from mice with ovalbumin-induced asthma by IF staining. CX3CR1 was increased in the subepithelial layer of the airway by IHC staining. Moreover, CX3CR1 small interfering (si)RNA downregulated TGF-β-induced CTGF and fibronectin expression in NHLFs. CX3CL1 induced CTGF and fibronectin expression in NHLFs. TGF-β-induced CX3CL1 secretion from NHLFs. Furthermore, TP213 decreased TGF-β-induced CTGF, fibronectin, and α-SMA expression in NHLFs. Mitochondrion-related differentially expressed genes (DEGs) were examined after CX3CL1 neutralization in TGF-β-treated NHLFs. TP213 alleviated TGF-β-induced mitochondrial dysfunction and apoptosis resistance in NHLFs. CX3CL1 induced p65, IκBα, and IKKα phosphorylation in a time-dependent manner. Furthermore, CX3CL1-induced fibronectin expression and JC-1 monomer were decreased by p65 siRNA. TP213 reduced TGF-β-induced p65 and α-SMA expression in NHLFs. These findings suggest that neutralizing CX3CL1 attenuates lung fibroblast activation and mitochondrial dysfunction. Understanding the impacts of CX3CL1 neutralization on fibroblast mitochondrial function could contribute to the development of therapeutic strategies for managing airway remodeling in severe asthma.

The Role of Collagen VIII in the Aging Mouse Kidney.

The gradual loss of kidney function due to increasing age is accompanied by structural changes such as fibrosis of the tissue. The underlying molecular mechanisms are complex, but not yet fully understood. Non-fibrillar collagen type VIII (COL8) could be a potential factor in the fibrosis processes of the aging kidney. A pathophysiological significance of COL8 has already been demonstrated in the context of diabetic kidney disease, with studies showing that it directly influences both the development and progression of renal fibrosis occurring. The aim of this study was to investigate whether COL8 impacts age-related micro-anatomical and functional changes in a mouse model. The kidneys of wild-type (Col8-wt) and COL8-knockout (Col8-ko) mice of different age and sex were characterized with regard to the expression of molecular fibrosis markers, the development of nephrosclerosis and renal function. The age-dependent regulation of COL8 mRNA expression in the wild-type revealed sex-dependent effects that were not observed with collagen IV (COL4). Histochemical staining and protein analysis of profibrotic cytokines TGF-β1 (transforming growth factor) and CTGF (connective tissue growth factor) in mouse kidneys showed significant age effects as well as interactions of the factors age, sex and Col8 genotype. There were also significant age and Col8 genotype effects in the renal function data analyzed by urinary cystatin C. In summary, the present study shows, for the first time, that COL8 is regulated in an age- and sex-dependent manner in the mouse kidney and that the expression of COL8 influences the severity of age-induced renal fibrosis and function.