Cardiac fibrosis, a major pathological hallmark of aging that leads to heart failure, is characterized by excessive collagen deposition. Our knowledge of what sustains collagen synthesis in the aging heart is still very preliminary. Here, we uncover a central role for chaperone-mediated autophagy (CMA), a selective lysosomal degradation pathway, in this process. We demonstrate that CMA is suppressed in the aging heart, which promotes collagen overproduction in fibroblasts, whereas enhancing CMA activity ameliorates fibrosis and diastolic dysfunction. Mechanistically, we identify SHMT2 (serine hydroxymethyltransferase 2) as a CMA substrate whose accumulation with aging drives collagen synthesis by increasing glycine availability. Integrative omics revealed a systemic downregulation of the ketone body β-hydroxybutyrate (BHB) in aged mice. BHB supplementation - via a cyclic ketogenic diet - restored CMA, attenuated fibrosis, and improved cardiac function. This recovery was mediated through BHB-induced activation of the HCAR2 receptor and subsequent phosphorylation of HSPA8/HSC70, which systemically reactivates the CMA machinery. Furthermore, we show that Lycium barbarum polysaccharide (LBP) rejuvenates hepatic ketogenesis and mimics the benefits of BHB. Our findings establish a BHB-HCAR2-CMA-SHMT2 regulatory axis as a critical mechanism driving aging-related cardiac fibrosis and highlight nutritional strategies that target CMA as promising therapies against cardiac aging.Abbreviations AcAc: acetoacetic acid; BHB: β-hydroxybutyrate; CMA: chaperone-mediated autophagy; COL1: collagen type I; COL3: collagen type III; ECM: extracellular matrix; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HCAR2: hydroxycarboxylic acid receptor 2; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; HF: heart failure; HK2: hexokinase 2; IVRT: isovolumic relaxation time; KD: ketogenic diet; LAMP2A: lysosome associated membrane protein 2A; LBP:Lycium barbarumpolysaccharide; PKM/PKM2: pyruvate kinase M1/2; SHMT2: serine hydroxymethyltransferase 2; VIM: vimentin.

Objective To explore the role of succinate in age-related cardiac fibrosis and its mechanisms. Methods In this study, we established three experimental models: naturally aged mice, young mice administered succinate by drinking water, and cultured NIH/3T3 fibroblasts exposed to succinate. Determine the concentration of succinate in serum and myocardial tissue from these samples. Protein levels of GPR91, HIF-1α, and fibrosis-related markers were measured along with TGF-β1 secretion and Smad2/3 phosphorylation. Overexpression and inhibition experiments were conducted to verify the signal axis. Results Aged mice and those that received succinate in their drinking water both showed significantly higher levels of succinate in the serum and heart tissue, with increased expression of the succinate receptor GPR91. After oral administration of succinate to young mice, myocardial fibrosis occurred that was similar to the changes in old age. In cultured NIH/3T3 cells, succinate exposure promoted a fibrotic phenotype. Further investigation found that succinate first increased the expression of GPR91, then promoted HIF-1α expression, leading to an increase in TGF-β1 secretion and Smad2/3 phosphorylation. Blocking either GPR91 or HIF-1α can prevent these fibrotic changes; However, when TGF-β1 is added, the phenotype in cells that have been inhibited for GPR91 will return. Notably, a Smad pathway inhibitor completely abolished the succinate-induced fibrosis. Conclusion In conclusion, succinate induces cardiac fibrosis through the GPR91-HIF-1α-TGF-β1-Smad signaling pathway.”

Age-related cardiac fibrosis is a key driver of heart failure and hallmark of aging whose mechanisms remain incompletely understood. Here we show elevated succinate levels in aged mice and humans drive cardiac fibrosis by enhancing fibroblast activation and collagen production. This process is mediated through succinate-dependent succinylation of PKM2 at lysine 125, promoting its transition from tetrameric to dimeric states. Using SUCNR1–/– mice, we establish that succinate signaling through SUCNR1/GPR91 promotes PKM2 succinylation and dimerization, creating a profibrotic network associated with aging-related diastolic dysfunction. Nuclear translocation of dimeric PKM2 enables fibroblast activation through HIF-1α binding, enhancing DNA-binding affinity and upregulating fibrogenic genes. Metformin treatment suppresses fibroblast activation by reducing succinate accumulation, revealing therapeutic potential for mitigating age-related cardiac fibrosis and diastolic dysfunction. Our findings identify metabolic dysregulation as a critical target and characterize a succinate-PKM2 signaling axis whose interruption may attenuate cardiac aging. Elevated succinate in aging drives cardiac fibrosis by inducing PKM2 succinylation, dimerization, and nuclear translocation, activating fibroblasts. Targeting this axis may slow cardiac aging

Regular moderate physical exercise is beneficial for the cardiovascular system. Our prior study has demonstrated a long-term moderate exercise (4-week of 60-min 74.0% V̇O2max treadmill running) is optimal in protecting from exhaustive exercise-induced cardiac ischemic injury. This study is aimed to investigate the effect of long-term moderate exercise on myocardial metabolome in rats. Thirteen male Sprague-Dawley rats were randomly assigned into the control group (C) and the long-term moderate exercise group (E). The targeted metabolomics of the myocardium was analyzed by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) system. Results showed that the metabolites categories of bile acids (BAs), fatty acids (FAs), and phenylpropanoic acids were significantly decreased. The biosynthesis of unsaturated FAs pathway was significantly downregulated. The altered metabolites in the E Group included decreased FAs (pentadecanoic acid, 10Z-heptadecenoic acid, dihomo-gamma-linolenic acid, docosahexaenoic acid, docosapentaenoic acid, and 10Z-nonadecenoic acid), decreased BAs (chenodeoxycholic acid and beta-muricholic acid), decreased organic acids (glycolic acid and 2-hydroxyglutaric acid), decreased carbohydrate (N-acetylneuraminic acid, Neu5Ac), decreased amino acids (α-aminobutyric acid and norvaline), decreased phenylpropanoic acids (hydroxyphenyllactic acid), and benzoic acids (4-hydroxybenzoic acid and phthalic acid). The results indicated that long-term moderate exercise has promoted lipids utilization in myocardium while exerted little influence on carbohydrate metabolism and diminished many detrimental metabolites. Notably, decrease of myocardial carbohydrate Neu5Ac after long-term moderate exercise might predict a prospective metabolomics biomarker for cardioprotection. This research has displayed the effect of long-term moderate exercise on myocardial metabolomic profiling in rats and indicated some promising metabolites which can be applied for exercise benefits in future.

Idiopathic pulmonary fibrosis (IPF) is characterized by excessive deposition of extracellular matrix in the lung with fibroblast-to-myofibroblast transition, leading to chronically compromising lung function and death. However, very little is known about the metabolic alterations of fibroblasts in IPF, and there is still a lack of pharmaceutical agents to target the metabolic dysregulation. Here we show a glycolysis upregulation and fatty acid oxidation (FAO) downregulation in fibroblasts from fibrotic lung, and perturbation of glycolysis and FAO affects fibroblasts transdifferentiation. In addition, there is a significant accumulation of succinate both in fibrotic lung tissues and myofibroblasts, where succinate dehydrogenase (SDH) operates in reverse by reducing fumarate to succinate. Then succinate contributes to glycolysis upregulation and FAO downregulation by stabilizing HIF-1α, which promotes the development of lung fibrosis. In addition, we identify a near-infrared small molecule dye, IR-780, as a targeting agent which stimulates mild inhibition of succinate dehydrogenase subunit A (SDHA) in fibroblasts, and which inhibits TGF-β1 induced SDH and succinate elevation, then to prevent fibrosis formation and respiratory dysfunction. Further, enhanced cell retention of IR-780 is shown to promote severe inhibition of SDHA in myofibroblasts, which may contribute to excessive ROS generation and selectively induces myofibroblasts to apoptosis, and then therapeutically improves established lung fibrosis in vivo. These findings indicate that targeting metabolic dysregulation has significant implications for therapies aimed at lung fibrosis and succinate dehydrogenase is an exciting new therapeutic target to treat IPF.

ObjectivesIntestinal mucositis is the major side effect during abdominal or pelvic radiotherapy, but the underlying immunogen remains to be further characterised and few radioprotective agents are available. This study investigated the role of dsDNA-triggered inflammasomes in intestinal mucositis during radiotherapy. MethodsPro-inflammatory cytokines were detected by ELISA. Radiation-induced intestinal injury in mice was analyzed by means of survival curves, body weight, HE staining of intestines, and intestinal barrier integrity. Western blot, immunofluorescence staining, co-immunoprecipitation assay and flow cytometry were used to investigate the regulatory role of dsDNA on inflammasomes. ResultsHere, we show that a high level of IL-1 beta and IL-18 is associated with diarrhoea in colorectal cancer (CRC) patients during radiotherapy, which accounts for intestinal radiotoxicity. Subsequently, we found that the dose-dependently released dsDNA from the intestinal epithelial cells (IECs) serves as the potential immunogenic molecule for radiation-induced intestinal mucositis. Our results further indicate that the released dsDNA transfers into the macrophages in an HMGB1/RAGE-dependent manner and then triggers absent in melanoma 2 (AIM2) inflammasome activation and the IL-1 beta and IL-18 secretion. Finally, we show that the FDA-approved disulfiram (DSF), a newly identified inflammasome inhibitor, could mitigate intestinal radiotoxicity by controlling inflammasome. ConclusionThese findings indicate that the extracellular self-dsDNA released from the irradiated IECs is a potential immunogen to stimulate immune cells and trigger the subsequent intestinal mucositis, while blunting the dsDNA-triggered inflammasome in macrophages may represent an exciting therapeutic strategy for side effects control during abdominal radiotherapy.

The effect of different duration of exercise preconditioning (EP) on protecting from exhaustive exercise-induced cardiac injury (EECI) has been optimized in rats. Male Sprague-Dawley rats were divided into six groups: the control group, exhaustive exercise (EE) group, EP 20-min + EE group, EP 40-min + EE group, EP 60-min + EE group and EP 80-min + EE group. The EP groups were subjected to treadmill running at the intensity of 74.0% V̇O2 max. Changes of exercise capacity, cardiac pathology, myocardial enzymology, electrocardiogram (ECG), cardiac function, and mitochondrial respiratory function were compared. Compared to the C group, the EE group has shown significant decrease of exercise capacity, elevation of serum N-terminal pro B-type natriuretic peptide (NT-proBNP) and cardiac troponin-I (cTn-I) levels, cardiac morphology change, ECG disturbance, cardiac dysfunction and reduction of myocardial mitochondrial respiration function. Compared to the EE group, the EP groups have shown significant elevation of exercise capacity, decrease of serum NT-proBNP and cTn-I, improvement of cardiac function and myocardial mitochondrial electron transfer pathway complex I, II and IV activity. The correlation analyses showed protection of EP was proportional to EP duration from 20-min to 60-min. EE caused cardiac injury. EP could protect from EECI by alleviating myocardial damage, improving cardiac function and mitochondrial ETP complex I, II and IV activity. EP protection was positively correlated to EP duration from 20-min to 60-min with EP intensity fixed at 74.0% V̇O2 max.

目的 探究碎裂QRS波在新战士复检中的发生率、 分布特点及在训练中的预警意义.方法 回顾性分析某部3954例(男性3631例,女性323例)入伍新战士复检心电图,收集静息状态下的常规12导联心电图,筛选出fQRS波,统计fQRS波的发生率及发生部位.依据年龄18～25岁划分为八个组,男兵按兵种分为六组:空军1部、陆军1部、武警、通讯、空军2部、陆军2部,再按fQRS波出现导联分为肢导组、胸导组、胸导+肢导组.结果 fQRS波的整体发生率在性别和年龄上无统计学差异(P>0.05).fQRS发生率在入伍战士各年龄段无统计学差异(P>0.05).六个兵种男兵fQRS波发生率之间存在统计学差异(P<0.05).fQRS波同时发生于胸导和肢导的比例明显大于单纯发生于胸导/肢导的比例,具有显著差异(P<0.05).结论 fQRS波的发生率与运动强度之间具有一定联系,这种不同运动强度造成的fQRS波发生率之间差异可能与心肌损伤有一定关系.

OBJECTIVE:To investigate the effects of mitochondrion-targeted cyanine fluorescent small molecule IR-61 on cardiac injury induced by exhaustive exercise in rats.METHODS:Thirty-six adult male SD rats were randomly divided into 3 groups(n=12),control group (Ctrl), exhaustive exercise group (EE) and IR-61+ exhaustive exercise group (IR-61+EE). IR-61+EE group were intraperitoneally injected with 2 mg/kg IR-61 at the same time on day 1, 4 and 7. One hour after the end of the last drug administration, the two exhaustive exercise groups were subjected to exhaustive exercise modeling. The rats were placed on an animal treadmill with a slope of 0° at a speed of 10~15 m/min to coordinate their limbs running posture, and then ran at a speed of 25~30 m/min until exhaustion about 15 minutes later. After the animal models established, ECG was recorded by physiological recorder, myocardial injury was observed by light microscope, mitochondrial injury was observed by transmission electron microscope, myocardial cell apoptosis was detected by TUNEL method, markers of myocardial injury were detected by ELISA, and myocardial mitochondrial respiration rate was measured by high-resolution Oxygraph-2K mitochondrial instrument.RESULTS:① Compared with Ctrl group, heart rate was increased, PR interval was shortened, QRS interval was prolonged, QTc was prolonged and ST segment was depressed significantly in EE group (P＜0.05). In EE group, myocardial fiber fracture and mitochondrial inner chamber swelling were obvious, mitochondrial crest was fuzzy, mitochondrial outer membrane was incomplete, and a large number of mitochondrial rupture and fusion were visible. In EE group, TUNEL staining cells were abundant, chromatin concentration and marginalization, nuclear membrane lysis, chromatin fragmentation into massive apoptotic bodies, apoptosis score increased (P＜0.05). The levels of creatine kinase isoenzyme-MB (CK-MB), cardiac troponin I(cTn-I) and N-terminal B-type natriuretic peptide (NT-proBNP) were increased in EE group (P＜0.05). Basal respiration rate, oxidative respiration rate of fatty acids and respiration rate of complex Ⅰ, Ⅱ and Ⅳ were all decreased (P＜ 0.05). ② Compared with EE group, the heart rate in IR-61+EE group was increased, PR interval was prolonged, QRS interval was shortened, QTc was shortened, ST segment was not significantly depressed (P＜0.05). In IR-61+EE group, myocardial fiber arrangement was loose, no obvious fracture was observed, mitochondrial inner ventricle was swelling, mitochondrial outer membrane was intact, TUNEL stained cells and unstained cells were observed, the overall morphology was more similar to Ctrl group. Apoptosis index was decreased (P＜0.05), the levels of CK-MB and cTn-I were decreased in IR-61+EE group (P＜0.05). The oxidative respiration rate of fatty acids and the respiration rate of complex Ⅱ and Ⅳ were increased (P＜0.05).CONCLUSION:Mitochondrion-targeted cyanine fluorescent small molecule IR-61 can improve cardiac electrical activity, reduce myocardial cell injury and mitochondrial injury, reduce myocardial cell apoptosis, and improve the myocardial mitochondrial energy metabolism condition in exhausted rats.

Oxidative stress injury and subsequent inflammatory response are considered to play critical roles in radiation-induced lung injury (RILI). Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that regulates oxidative stress response and represses inflammation, but its therapeutic value in RILI remains elusive. Our previous studies have shown that the near-infrared (NIR) IR-61 dye evokes intracellular antioxidant defense by enhancing Nrf2 signaling and promoting anti-inflammatory effects. We established a model of RILI in mice exposed to whole-thoracic irradiation. The results showed that IR-61 treatment notably improved pulmonary functions by decreasing lung density and diminishing airway resistance. In addition, IR-61 significantly ameliorated radiation-induced inflammatory cell infiltration and proinflammatory cytokine (IL-1 beta, IL-6, and TNF-alpha) release, thereby mitigating inflammatory response. Furthermore, IR-61 mitigated radiation-induced lung fibrosis by decreasing the collagen deposition and the levels of fibrogenesis-related factors (collagen I, collagen III, alpha-SMA, and fibronectin). More importantly, IR-61 was found to accumulate in the mitochondria of macrophages in irradiated lung tissues. Therefore, the functions of IR-61 in macrophages were further studied in irradiated macrophage cell lines, MH-s and RAW 264.7 in vitro. The results indicated that IR-61 upregulated the expression of Nrf2 and heme oxygenase-1 (HO-1) and decreased the levels of reactive oxygen species (ROS) and pro-inflammatory cytokines (IL-1 beta and IL-6) in macrophages after radiation. In summary, our study suggests that IR-61 effectively mitigates RILI by activating Nrf2 signaling in irradiated lung tissues. In particular, Nrf2-mediated anti-inflammatory and antioxidant effects in irradiated lung tissue macrophages play critical roles in protecting against RILI.

Radiation-induced pulmonary fibrosis (RIPF) is a common complication during thoracic radiotherapy, but there are few effective treatments. Here, we identify IR-780, a mitochondria-targeted near-infrared (NIR) dye, can selectively accumulate in the irradiated lung tissues. Besides, IR-780 significantly alleviates radiation-induced acute lung injury and fibrosis. Furthermore, our results show that IR-780 prevents the differentiation of fibroblasts and the release of pro-fibrotic factors from alveolar macrophages induced by radiation. Besides, IR-780 downregulates the expression of glycolysis-associated genes, and 2-Deoxy-D-glucose (2-DG) also prevents the development of fibrosis in vitro, suggesting radioprotective effects of IR-780 on RIPF might be related to glycolysis regulation. Finally, IR-780 induces tumour cell apoptosis and enhances radiosensitivity in representative H460 and A549 cell lines. These findings indicate that IR-780 is a potential therapeutic small-molecule dye during thoracic radiotherapy.

Research on ageing-associated genes is important for investigating ageing and anti-ageing strategies. Here, we firstly reported that the human positive cofactor 4 (PC4), a multifunctional and highly conserved nucleoprotein, is accumulated and activated during ageing and causes global accelerated ageing process by disrupting proteostasis. Mechanistically, PC4 interacts with Sin3-HDAC complex and inhibits its deacetylated activity, leads to hyper-acetylation of the histones at the promoters of mTOR-related genes and causes mTOR signalling activation. Accordingly, mTOR activation causes excessive protein synthesis, resulting in impaired proteostasis and accelerated senescence. These results reveal a new biological function of PC4 in vivo, recognizes PC4 as a new ageing-associated gene and provides a genetically engineered mouse model to simulate natural ageing. More importantly, our findings also indicate that PC4 is involved in histone acetylation and serves as a potential target to improve proteostasis and delay ageing.

This study was to optimize the exercise preconditioning (EP) intensity in protecting from exhaustive exercise-induced cardiac injury (EECI). A total of 98 male Sprague-Dawley rats were divided into 7 groups (n ​= ​14): the control group (C), the exhaustive exercise group (EE) and the EP ​+ ​EE groups, which include the V10 (53.0%̇O2max), V15 (58.4%̇O2max), V20 (67.0%̇O2max), V26 (74.0%̇O2max) and V30 (80.0%̇O2max) groups. Except the C group, the other groups were subjected to treadmill running. The serum contents of N terminal pro B type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTn-I) were detected by the enzyme-linked immunosorbent assay method, ECG was recorded, heart function was detected by pressure volume catheter and the activities of mitochondrial electron transfer pathway (ET pathway) complexes I, Ⅱ and IV were measured by high-resolution respiration instrument. Compared to the EE group, the EP groups have shown decrease of NT-proBNP and cTn-I, improvement of mitochondrial respiratory function and cardiac function. Compared to other EP groups, the V26 group has shown significant decrease of myocardial enzymes and improvement of mitochondrial function. The correlation analysis showed the EP effect was proportional to EP intensity in the range of 53.0%̇O2max-74.0%̇O2max. High intensity and long duration of exhaustive exercise caused cardiac injury and EP could decrease serum level of NT-proBNP and cTn-I, improve electrical derangement and the left ventricular function, and raise the activities of ET pathway complexes I, Ⅱ and IV. The protection of EP on EECI was improved as the EP intensity was increased from 53.0%̇O2max to 74.0%̇O2max and when EP intensity was 74.0%̇O2max, the effect was the most obvious among all the setting EP groups.

Pro-inflammatory activation of adipose tissue macrophages (ATMs) is causally linked to obesity and obesity-associated disorders. A number of studies have demonstrated the crucial role of mitochondrial metabolism in macrophage activation. However, there is a lack of pharmaceutical agents to target the mitochondrial metabolism of ATMs for the treatment of obesity-related diseases. Here, we characterize a near-infrared fluorophore (IR-61) that preferentially accumulates in the mitochondria of ATMs and has a therapeutic effect on diet-induced obesity as well as obesity-associated insulin resistance and fatty liver. IR-61 inhibits the classical activation of ATMs by increasing mitochondrial complex levels and oxidative phosphorylation via the ROS/Akt/Acly pathway. Taken together, our findings indicate that specific enhancement of ATMs oxidative phosphorylation improves chronic inflammation and obesity-related disorders. IR-61 might be an anti-inflammatory agent useful for the treatment of obesity-related diseases by targeting the mitochondria of ATMs.

Aberrant iron homeostasis is a typical characteristic of Hepatocellular carcinoma (HCC), and perturbation of iron metabolism is an effective strategy for HCC therapy. However, there are few safe and effective targeting agents available in clinical practices. The artemisinin and its derivatives have shown potential anti-cancer activity by disturbing cellular iron homeostasis, but the specific mechanism is still unclear. In this study, we demonstrate that Artesunate (ART), a water-soluble anti-malaria agent in clinical use, can regulate the labile iron pool (LIP) and effectively induce ROS-dependent cell death in multiple HCC cells. Mechanistically, ART increases the LIP by promoting lysosomal degradation of iron-storage protein ferritin through acidizing lysosomes. Then the accumulation of labile iron in the endoplasmic reticulum (ER) promotes excessive reactive oxygen species (ROS) production and severe ER disruption, which leads to cell death. Our results provide a new understanding of how ART modulates iron metabolism in HCC cells at the subcellular level, demonstrate the significance of endoplasmic reticulum as iron-vulnerability of HCC cells. More importantly, our findings suggest ART is a safe and potential anti-HCC agent via disturbing iron homeostasis.

Chronic wounds include, but are not limited to, radiation ulcers, pressure ulcers, vascular ulcers and diabetic foot ulcers. These chronic wounds can persist for years without healing and severe ulcers may lead to amputation. Unfortunately, the underlying pathologies of refractory chronic wounds are not fully characterized, and new treatments are urgently needed. Recently, increasing evidence has indicated that cell senescence plays an important role in the development of chronic wounds, and preventing cell senescence or removing senescent cells holds promise as a new therapeutic strategy. In this review, we aim to probe these latest findings to promote the understanding of cellular senescence in the pathological process and potential management of chronic wounds.

Abstract Chronic wounds include, but are not limited to, radiation ulcers, pressure ulcers, vascular ulcers and diabetic foot ulcers. These chronic wounds can persist for years without healing and severe ulcers may lead to amputation. Unfortunately, the underlying pathologies of refractory chronic wounds are not fully characterized, and new treatments are urgently needed. Recently, increasing evidence has indicated that cell senescence plays an important role in the development of chronic wounds, and preventing cell senescence or removing senescent cells holds promise as a new therapeutic strategy. In this review, we aim to probe these latest findings to promote the understanding of cellular senescence in the pathological process and potential management of chronic wounds.

Metformin has effective therapeutic effects in anti-tumor and anti-fibrotic diseases. However, how the antifibrotic effect of metformin in the eye and how it is transferred are still unclear. Here, the eye drop of metformin treatment was studied in Sprague-Dawley (SD) rats of glaucoma filtrating surgery (GFS). Rats were administered randomly bilateral drops: control group (without surgery), GFS group, metformin group or mitomycin C (MMC) group (sponge application intraoperatively, 0.02%). Bleb features and intraocular pressure (IOP) were assessed for postoperative week 4. Metformin effectively inhibited fibrosis and improved the surgical outcomes of GFS.In vitro, we found that the degree of oxidative stress and fibrosis in metformin pretreated-Human Conjunctival Fibroblasts (HConFs) were reduced; the pro-fibrotic response of HConFs were decreased by inducing macrophagic polarity changes. Besides, the inhibition of nuclear factor erythroid 2-related factor 2 (Nrf2)/AMP-activated protein kinase (AMPK) and the competition of organic cation transporters (OCTs) effectively reduced the anti-fibrotic capability of metformin. Together, this experiment indicates that metformin enters into HConFs cell with OCTs, which can protect against filtrating blebs scar formation in SD rats of GFSviaactivating AMPK/Nrf2 axis and the downregulation of profibrogenic and inflammatory biomarkers.

Objective To evaluate the effects of IR-61 on the development of pulmonary fibrosis and on the proliferation and migration of lung fibroblasts in rats. Methods Forty male SD rats (6 to 8 weeks old) were randomized equally into normal control group, IR-61 group, bleomycin group and bleomycin+IR-61 group. In the latter 2 groups, rat models of pulmonary fibrosis were established by intratracheal infusion of bleomycin (2.5 mg/kg). In the 2 groups with IR-61 treatment, IR-61 was intraperitoneally injected at the dose of 2.0 mg/kg 30 min following intratracheal bleomycin infusion and was then administered twice a week. At 10 d after bleomycin treatment, 3 rats from each group were selected for IR-61 injection (2 mg/kg) via the tail vein to observe the accumulation of IR-61 in each organ at 24 h using near infrared fluorescence imaging (NIR). After 28 d of treatment, the rats were euthanized and the lung tissue was collected for HE and Masson staining. RT-PCR and Western blotting were performed to detect the changes of the expression of the genes related with lung fibroblast transdifferentiation and proliferation (including Collagen-1, Collagen-3, α-SMA, fibronectin, FOXM1, CCNB1, CDC25b and AURKB) in human lung fibroblasts (HFL1) and primary rat lung fibroblasts in response to IR-61 and transforming growth factor-β1 (TGF-β1) treatments; the migration of the cells was assessed using cell scratch test. Results NIR imaging showed that IR-61 could target the injured lung tissue induced by bleomycin. Morphological observation showed that compared with bleomycin-treated rats, the rats with IR-61 treatment presented with better structural integrity of the lungs with less obvious lung collapse, fewer fibrotic nodules and a significantly milder of pulmonary fibrosis (0.103 3±0.014 53 vs 0.460 0±0.037 86, P < 0.05). In HFL1 cells and primary rat lung fibroblasts, IR-61 pretreatment prior to TGF-β1 stimulation resulted in significantly lowered mRNA and protein expression of collagen-1, collagen-3, α-SMA, and fibronectin as well as the proliferation-specific genes FOXM1, CCNB1, CDC25b and AURKB (P < 0.05). Cell scratch test showed that TGF-β1 treatment significantly increased the cell migration activity, which was effectively suppressed by IR-61 treatment. Conclusion IR-61 ameliorates bleomycin-induced pulmonary fibrosis in rats by targeting the injured lung tissue and inhibiting the transdifferentiation, proliferation and migration of lung fibroblasts