Bufei Jianpi Granules Reduce Quadriceps Muscular Cell Apoptosis by Improving Mitochondrial Function in Rats with Chronic Obstructive Pulmonary Disease

Shenshuai Yingyang Jiaonang ameliorates chronic kidney disease-associated muscle atrophy in rats by inhibiting ferroptosis mediated by the HIF-1α/SLC7A11 pathway

Objective

Shenshuai Yingyang Jiaonang (SSYYJN), a traditional Chinese medicine formula, can ameliorate muscle atrophy associated with chronic kidney disease (CKD). However, its mechanisms of action remain unclear. This study is to investigate the molecular mechanisms involved in the effects of SSYYJN in ameliorating muscle atrophy associated with CKD in rats. Methods: The chemical compounds of SSYYJN were identified by UPLC-Q-Orbitrap HRMS. Considering the dose-response relationship of the identified compounds, male SD rats were randomly divided into Sham, Model, SSYYJN, and α-Keto Acid (KA) groups. Subsequently, we assessed the therapeutic and anti-ferroptotic effects of SSYYJN. Network pharmacology studies were used to predict the molecular mechanism of SSYYJN on ferroptosis and were further verified for accuracy.

Results

A total of 42 active compounds were identified from SSYYJN. SSYYJN alleviated muscle atrophy caused by CKD, as evidenced by changes in body weight, serum biochemical indices, mass and histopathology of the skeletal muscle, and the levels of MuRF1. SSYYJN reduced the levels of iron, MDA, and ROS, increased the levels of GSH, NAPDH, and Gpx4. Network pharmacology analysis indicated that SSYYJN exerted anti-ferroptotic effects that were closely related to the HIF-1α signaling pathway. Molecular protein and genetic test results showed that SSYYJN increased HIF-1α protein and increased SLC7A11.

Conclusions

SSYYJN attenuates muscle atrophy in CKD by inhibiting ferroptosis through the activation of the HIF-1α/SLC7A11 pathway and might be a promising traditional Chinese medicine for muscle atrophy in CKD.

Regulation of ARGs abundance by biofilm colonization on microplastics under selective pressure of antibiotics in river water environment

Interactions of microplastics (MPs) biofilm with antibiotic resistance genes (ARGs) and antibiotics in aquatic environments have made microplastic biofilm an issue of keen scholarly interest. The process of biofilm formation and the degree of ARGs enrichment in the presence of antibiotic-selective pressure and the impact on the microbial community need to be further investigated. In this paper, the selective pressure of ciprofloxacin (CIP) and illumination conditions were investigated to affect the physicochemical properties, biomass, and extracellular polymer secretion of polyvinyl chloride (PVC) microplastic biofilm. In addition, relative copy numbers of nine ARGs were analyzed by real-time quantitative polymerase chain reaction (qPCR). In the presence of CIP, microorganisms in the water and microplastic biofilm were more inclined to carry associated ARGs (2-3 times higher), which had a contributing effect on ARGs enrichment. The process of pre-microplastic biofilm formation might have an inhibitory effect on ARGs (total relative abundance up to 0.151) transfer and proliferation compared to the surrounding water (total relative abundance up to 0.488). However, in the presence of CIP stress, microplastic biofilm maintained the abundance of ARGs (from 0.151 to 0.149) better compared to the surrounding water (from 0.488 to 0.386). Therefore, microplastic biofilm act as abundance buffer island of ARGs stabilizing the concentration of ARGs. In addition, high-throughput analyses showed the presence of antibiotic-resistant (Pseudomonas) and pathogenic (Vibrio) microorganisms in biofilm under different conditions. The above research deepens our understanding of ARGs enrichment in biofilm and provides important insights into the ecological risks of interactions between ARGs, antibiotics, and microplastic biofilm.

Main Pathogenic Mechanisms and Recent Advances in COPD Peripheral Skeletal Muscle Wasting

Chronic obstructive pulmonary disease (COPD) is a worldwide prevalent respiratory disease mainly caused by tobacco smoke exposure. COPD is now considered as a systemic disease with several comorbidities. Among them, skeletal muscle dysfunction affects around 20% of COPD patients and is associated with higher morbidity and mortality. Although the histological alterations are well characterized, including myofiber atrophy, a decreased proportion of slow-twitch myofibers, and a decreased capillarization and oxidative phosphorylation capacity, the molecular basis for muscle atrophy is complex and remains partly unknown. Major difficulties lie in patient heterogeneity, accessing patients' samples, and complex multifactorial process including extrinsic mechanisms, such as tobacco smoke or disuse, and intrinsic mechanisms, such as oxidative stress, hypoxia, or systemic inflammation. Muscle wasting is also a highly dynamic process whose investigation is hampered by the differential protein regulation according to the stage of atrophy. In this review, we report and discuss recent data regarding the molecular alterations in COPD leading to impaired muscle mass, including inflammation, hypoxia and hypercapnia, mitochondrial dysfunction, diverse metabolic changes such as oxidative and nitrosative stress and genetic and epigenetic modifications, all leading to an impaired anabolic/catabolic balance in the myocyte. We recapitulate data concerning skeletal muscle dysfunction obtained in the different rodent models of COPD. Finally, we propose several pathways that should be investigated in COPD skeletal muscle dysfunction in the future.

Identification of Potential Key Genes in the Pathogenesis of Chronic Obstructive Pulmonary Disease Through Bioinformatics Analysis

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease with high morbidity and mortality. The etiology of COPD is complex, and the pathogenesis mechanisms remain unclear. In this study, we used rat and human COPD gene expression data from our laboratory and the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs) between individuals with COPD and healthy individuals. Then, protein–protein interaction (PPI) networks were constructed, and hub genes were identified. Cytoscape was used to construct the co-expressed network and competitive endogenous RNA (ceRNA) networks. A total of 198 DEGs were identified, and a PPI network with 144 nodes and 355 edges was constructed. Twelve hub genes were identified by the cytoHubba plugin in Cytoscape. Of these genes, CCR3, CCL2, COL4A2, VWF, IL1RN, IL2RA, and CCL13 were related to inflammation or immunity, or tissue-specific expression in lung tissue, and their messenger RNA (mRNA) levels were validated by qRT-PCR. COL4A2, VWF, and IL1RN were further verified by the GEO dataset GSE76925, and the ceRNA network was constructed with Cytoscape. These three genes were consistent with COPD rat model data compared with control data, and their dysregulation direction was reversed when the COPD rat model was treated with effective-component compatibility of Bufei Yishen formula III. This bioinformatics analysis strategy may be useful for elucidating novel mechanisms underlying COPD. We pinpointed three key genes that may play a role in COPD pathogenesis and therapy, which deserved to be further studied.

Mitochondrial Dysfunction in Chronic Respiratory Diseases: Implications for the Pathogenesis and Potential Therapeutics

Mitochondria are indispensable for energy metabolism and cell signaling. Mitochondrial homeostasis is sustained with stabilization of mitochondrial membrane potential, balance of mitochondrial calcium, integrity of mitochondrial DNA, and timely clearance of damaged mitochondria via mitophagy. Mitochondrial dysfunction is featured by increased generation of mitochondrial reactive oxygen species, reduced mitochondrial membrane potential, mitochondrial calcium imbalance, mitochondrial DNA damage, and abnormal mitophagy. Accumulating evidence indicates that mitochondrial dysregulation causes oxidative stress, inflammasome activation, apoptosis, senescence, and metabolic reprogramming. All these cellular processes participate in the pathogenesis and progression of chronic respiratory diseases, including chronic obstructive pulmonary disease, pulmonary fibrosis, and asthma. In this review, we provide a comprehensive and updated overview of the impact of mitochondrial dysfunction on cellular processes involved in the development of these respiratory diseases. This not only implicates mechanisms of mitochondrial dysfunction for the pathogenesis of chronic lung diseases but also provides potential therapeutic approaches for these diseases by targeting dysfunctional mitochondria.

Bufei Jianpi Formula Improves Mitochondrial Function and Suppresses Mitophagy in Skeletal Muscle via the Adenosine Monophosphate-Activated Protein Kinase Pathway in Chronic Obstructive Pulmonary Disease

Skeletal muscle dysfunction, a striking systemic comorbidity of chronic obstructive pulmonary disease (COPD), is associated with declines in activities of daily living, reductions in health status and prognosis, and increases in mortality. Bufei Jianpi formula (BJF), a traditional Chinese herbal formulation, has been shown to improve skeletal muscle tension and tolerance via inhibition of cellular apoptosis in COPD rat models. This study aimed to investigate the mechanisms by which BJF regulates the adenosine monophosphate-activated protein kinase (AMPK) pathway to improve mitochondrial function and to suppress mitophagy in skeletal muscle cells. Our study showed that BJF repaired lung function and ameliorated pathological impairment in rat lung and skeletal muscle tissues. BJF also improved mitochondrial function and reduced mitophagy via the AMPK signaling pathway in rat skeletal muscle tissue. In vitro, BJF significantly improved cigarette smoke extract-induced mitochondrial functional impairment in L6 skeletal muscle cells through effects on mitochondrial membrane potential, mitochondrial permeability transition pores, adenosine triphosphate production, and mitochondrial respiration. In addition, BJF led to upregulated expression of mitochondrial biogenesis markers, including AMPK-α, PGC-1α, and TFAM and downregulation of mitophagy markers, including LC3B, ULK1, PINK1, and Parkin, with increased expression of downstream markers of the AMPK pathway, including mTOR, PPARγ, and SIRT1. In conclusion, BJF significantly improved skeletal muscle and mitochondrial function in COPD rats and L6 cells by promoting mitochondrial biogenesis and suppressing mitophagy via the AMPK pathway. This study suggests that BJF may have therapeutic potential for prophylaxis and treatment of skeletal muscle dysfunction in patients with COPD.

Recent progress in the use of mitochondrial membrane permeability transition pore in mitochondrial dysfunction-related disease therapies

Mitochondria have various cellular functions, including ATP synthesis, calcium homeostasis, cell senescence, and death. Mitochondrial dysfunction has been identified in a variety of disorders correlated with human health. Among the many underlying mechanisms of mitochondrial dysfunction, the opening up of the mitochondrial permeability transition pore (mPTP) is one that has drawn increasing interest in recent years. It plays an important role in apoptosis and necrosis; however, the molecular structure and function of the mPTP have still not been fully elucidated. In recent years, the abnormal opening up of the mPTP has been implicated in the development and pathogenesis of diverse diseases including ischemia/reperfusion injury (IRI), neurodegenerative disorders, tumors, and chronic obstructive pulmonary disease (COPD). This review provides a systematic introduction to the possible molecular makeup of the mPTP and summarizes the mitochondrial dysfunction-correlated diseases and highlights possible underlying mechanisms. Since the mPTP is an important target in mitochondrial dysfunction, this review also summarizes potential treatments, which may be used to inhibit pore opening up via the molecules composing mPTP complexes, thus suppressing the progression of mitochondrial dysfunction-related diseases.

MiR-195-5p inhibits the development of chronic obstructive pulmonary disease via targeting siglec1

Chronic obstructive pulmonary disease (COPD), characterized by chronic inflammation, is a recognized global health crisis. Sialic acid-binding immunoglobulin-like lectin 1 (siglec1 or CD169), mainly expressed in macrophages and dendritic cells, is markedly upregulated after encountering pathogens or under acute/chronic inflammation conditions. However, it is rarely reported that whether siglec1 plays a role in the development of COPD. In this study, we found that siglec1 had higher expression in the lungs from COPD rats and in peripheral blood mononuclear cells (PBMCs) from COPD patients. Knockdown of siglec1 in vivo and in vitro dramatically decreased pro-inflammatory cytokines production in pulmonary macrophages and alleviated pulmonary inflammatory responses in COPD rats as well as inactivated nuclear factor kappa B (NF-κB) signaling. In addition, we identified a new microRNA, miR-195-5p, which has never explored in COPD, was lower expressed in COPD rats and PBMC of COPD patients, and could negatively modulate siglec1 expression in macrophages. Moreover, overexpression of miR-195-5p via miR-195-5p mimics in vitro and in vivo could significantly alleviate pro-inflammatory cytokines production in pulmonary macrophages and pulmonary inflammatory responses in COPD rats. Together, our findings suggested that miR-195-5p inhibited the development of COPD via targeting siglec1, which might become a therapeutic target to improve COPD.

Recent advances on animal models related to chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) has become an important public health problem in the world. According to reports, COPD ranks fourth in the global cause of death, causing a serious economic burden on society. The pathogenesis of COPD is complex, making it difficult to simulate the pathological changes and clinical features of COPD. Moreover, the COPD animal model has an irreplaceable role in the study of etiology, pathology and treatment. It is worth noting that the risk factors for chronic obstructive pulmonary disease persist, and the economic burden of global chronic obstructive pulmonary disease is expected to continue to increase in the coming decades. Establishing a standardized, a clinically realistic COPD animal model has always been a research direction that scholars are keen on. Therefore, it is essential to establish an economical animal model. The establishment of a suitable animal model can accurately simulate the pathological features of human chronic obstructive pulmonary disease and help to develop effective interventions and treatments in a short period of time. This review integrates the experimental animal species selected in the animal models used in COPD studies. Subsequently, different methods and mechanisms for establishing animal models were summarized according to different modeling factors. Finally, the criteria for evaluating existing animal models are discussed. It is hoped that the summary of this paper will guide the establishment of relevant animal models for future COPD research.

Muscle death participates in myofibrillar abnormalities in FHL1 knockout mice

BACKGROUND

Mutations in the four and-a-half LIM domain protein 1 (FHL1) gene or FHL1 protein deletion have been identified as the cause of rare hereditary myopathies or cardiomyopathies. In our previous study, autophagy activation was associated with myofibrillar abnormalities in FHL1 knockout (KO) mice. P2RX7 induces cell death, such as autophagy, pyroptosis or apoptosis via cell-specific downstream signaling; however, the roles of P2RX7 in pyroptosis or apoptosis in myofibrillar abnormalities in FHL1 KO mice have not been well elucidated.

METHODS

In this study, skeletal muscle and heart of 2.5 months old WT and FHL1 KO male mice histomorphology were examined by hematoxylin and eosin staining. The indicators for pyroptosis (NLRP3; ASC; cleaved-caspase1; IL-1β), apoptosis (Apaf-1; Bcl-2; caspase9; cleaved-caspase3), and P2RX7 were detected in the triceps (Tri), tibialis anterior muscles (TA), and heart by western blot and/or immunohistochemistry in WT and FHL1 KO male mice.

RESULTS

Indicators for pyroptosis (ASC; cleaved-caspase1; IL-1β) and apoptosis (Apaf-1 and cleaved-caspase3), as well as P2RX7 were upregulated in Tri, tibialis TA, and heart in FHL1 KO mice, indicating pyroptosis and apoptosis play important roles in myofibrillar abnormalities in FHL1 KO mice.

CONCLUSIONS

P2RX7 may participate in myofibrillar abnormalities by activating pyroptosis and apoptosis in FHL1 KO mice. These findings have basic implications for the understanding of myopathies induced by FHL1 deficiency and provide new avenues for the treatment of these hereditary myopathies by modulating P2RX7.

Trichostatin A inhibits skeletal muscle atrophy induced by cigarette smoke exposure in mice

AIMS

It is well known that cigarette smoke (CS) is the main risk factor for chronic obstructive pulmonary disease (COPD) accompanied by skeletal muscle atrophy. Histone deacetylases (HDACs) that remove acetyl groups from target proteins are necessary for the muscle atrophy associated with skeletal muscle disuse. However, the role of HDACs and trichostatin A (TSA), a HDAC inhibitor, in skeletal muscle atrophy caused by CS exposure remains poorly understood.

MAIN METHODS

Female mice were exposed to CS twice daily for 40 days and TSA injected intraperitoneally into CS-exposed mice on alternate days. Skeletal muscles were weighed and gastrocnemius (Gas) muscle histomorphology examined by hematoxylin and eosin staining. Histone deacetylases 1 and 2 (HDAC1/2), and markers of ubiquitin degradation, muscle differentiation, apoptosis, pyroptosis, and the cytoskeletal proteins were assessed by western blot and immunohistochemistry in Gas.

KEYFINDINGS

CS exposure decreased body and skeletal muscle weights and triggered an increase in the percentage of fiber with centralized nuclei in Gas. HDAC1/2 proteins were upregulated in the Gas of mice exposed to CS, while TSA effectively inhibited HDAC1/2 protein levels and attenuated the loss of body weight and skeletal muscle wet weight induced by CS exposure. Markers for ubiquitin degradation, muscle differentiation, cytoskeletal proteins, apoptosis and pyroptosis were all upregulated following CS exposure and effectively restored by TSA.

SIGNIFICANCE

TSA may inhibit skeletal muscle atrophy and histomorphological alterations induced by CS exposure by downregulating markers of ubiquitin degradation, muscle fiber differentiation, cytoskeletal proteins, apoptosis and pyroptosis via HDAC1/2 inhibition.