Effects of exercise interventions on physical, psychological and social outcomes in frail older adults: An overview of systematic reviews.

AIMS: To comprehensively synthesise existing evidence from systematic reviews regarding the effects of exercise interventions on physical, psychological and social outcomes in frail older adults to provide reference for clinical practice. BACKGROUND: Frailty is highly prevalent in older adults and associated with increased adverse health outcomes. Some systematic reviews have assessed the effectiveness of exercise interventions in frail older adults with varied inclusion criteria, methodology quality, types of exercise and outcome measures. DESIGN: An overview of systematic reviews reported following the PRISMA checklist. METHODS: PubMed, Embase, CINAHL, Web of Science and Cochrane database were searched from inception until June 2023 to identify relevant systematic reviews with or without meta-analysis of randomised controlled trails. Two reviewers independently selected articles, extracted data, assessed quality and summarised findings. RESULTS: A total of 17 systematic reviews were included, with methodology quality varying from moderate to critically low. The most frequent types of exercise were multicomponent exercise and resistance-based exercise in community and long-term care facilities, respectively. Exercise interventions had positive effects on most physical outcomes and depression, but inconsistent effects on cognitive function and quality of life. The quality of the evidence for most outcomes was low and very low. CONCLUSIONS: This overview highlights the importance of exercise interventions to improve physical, psychological and social aspects in frail older adults and provides evidence on characteristics of exercise interventions for frailty in various settings. RELEVANCE TO CLINICAL PRACTICE: Multicomponent exercise and resistance-based exercise should be recommended for frail older adults. There is a need of more well-designed research with large sample size and validated definition of frailty. Long-term effects, adherence during and after exercise interventions, adverse events and cost-effectiveness should be emphasised in future studies. TRIAL AND PROTOCOL REGISTRATION: The overview protocol was registered on the International Prospective Register of Systematic reviews (CRD 42021281327). PATIENT OR PUBLIC CONTRIBUTION: No patient or public contribution. REPORTING METHOD: The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were applied to report the results.

HMGB1 promotes chemoresistance in small cell lung cancer by inducing PARP1-related nucleophagy.

INTRODUCTION: Small cell lung cancer (SCLC) is prone to chemoresistance, which is closely related to genome homeostasis-related processes, such as DNA damage and repair. Nucleophagy is the elimination of specific nuclear substances by cells themselves and is responsible for maintaining genome and chromosome stability. However, the roles of nucleophagy in tumour chemoresistance have not been investigated. OBJECTIVES: The aim of this work was to elucidate the mechanism of chemoresistance in SCLC and reverse this chemoresistance. METHODS: RNA-seq data from SCLC cohorts, chemosensitive SCLC cells and the corresponding chemoresistant cells were used to discover genes associated with chemoresistance and patient prognosis. In vitro and in vivo experiments were performed to verify the effect of high-mobility group box 1 (HMGB1) knockdown or overexpression on the chemotherapeutic response in SCLC. The regulatory effect of HMGB1 on nucleophagy was then investigated by coimmunoprecipitation (co-IP) and mass spectrometry (MS), and the underlying mechanism was explored using pharmacological inhibitors and mutant proteins. RESULTS: HMGB1 is a factor indicating poor prognosis and promotes chemoresistance in SCLC. Mechanistically, HMGB1 significantly increases PARP1-LC3 binding to promote nucleophagy via PARP1 PARylation, which leads to PARP1 turnover from DNA lesions and chemoresistance. Furthermore, chemoresistance in SCLC can be attenuated by blockade of the PARP1-LC3 interaction or PARP1 inhibitor (PARPi) treatment. CONCLUSIONS: HMGB1 can induce PARP1 self-modification, which promotes the interaction of PARP1 with LC3 to promote nucleophagy and thus chemoresistance in SCLC. HMGB1 could be a predictive biomarker for the PARPi response in patients with SCLC. Combining chemotherapy with PARPi treatment is an effective therapeutic strategy for overcoming SCLC chemoresistance.

METTL3 promotes chemoresistance in small cell lung cancer by inducing mitophagy.

BACKGROUND: Small cell lung cancer (SCLC) is the most aggressive subtype of lung cancer. Although most patients are initially sensitive to first-line combination chemotherapy with cisplatin and etoposide, chemotherapy drug resistance easily develops and quickly leads to tumour progression. Therefore, understanding the mechanisms of chemotherapy drug resistance and how to reverse it is key to improving the prognosis of patients with SCLC. Moreover, N6-methyladenosine (m6A) is the most abundant mRNA modification and is catalysed by the methyltransferase complex, in which methyltransferase-like 3 (METTL3) is the sole catalytic subunit. METHODS: The effects of METTL3 on chemoresistance in SCLC cells were determined using qRT-PCR, Western blotting, immunohistochemistry, cell counting kit (CCK-8) assays, flow cytometry, and tumorigenicity experiments. Methylated RNA immunoprecipitation sequencing (MeRIP-seq), MeRIP qPCR, immunofluorescence, and drug inhibitor experiments were performed to confirm the molecular mechanism of Decapping Protein 2 (DCP2), which is involved in the chemoresistance of SCLC. RESULTS: In the present study, we found that METTL3 is a marker for poor SCLC prognosis, and it is highly expressed in chemoresistant SCLC cells. METTL3 promotes SCLC chemoresistance by positively regulating mitophagy. METTL3 induces m6A methylation of DCP2 and causes the degradation of DCP2, which promotes mitochondrial autophagy through the Pink1-Parkin pathway, leading to chemotherapy resistance. We also found that STM2457, a novel METTL3 inhibitor, can reverse SCLC chemoresistance. CONCLUSIONS: The m6A methyltransferase METTL3 regulates Pink1-Parkin pathway-mediated mitophagy and mitochondrial damage in SCLC cells by targeting DCP2, thereby promoting chemotherapy resistance in patients with SCLC.

Effects of exercise interventions on physical and psychological outcomes in frail older adults: Protocol for an overview of systematic reviews.

AIMS: To systematically summarize the existing evidence regarding the effects of exercise interventions on physical and psychological outcomes in frail older adults and appraise the quality and strength of the evidence. DESIGN: An overview protocol. METHODS: A literature search of PubMed, Embase, Web of Science, CINAHL and Cochrane Database of Systematic Reviews will be conducted to identify relevant systematic reviews with or without meta-analysis on exercise interventions for frail older adults. Two independent reviewers will select articles, extract data and appraise the quality of included reviews. Physical and psychological outcomes will be synthesized using narrative summaries. The methodological quality of included reviews and the quality of evidence will also be assessed. RESULTS: This overview will present the evidence on the effects of exercise interventions on physical and psychological outcomes for frail older adults, contributing to the implementation of exercise interventions to improve health outcomes for this population.

Prevalence and risk factors of cognitive frailty in community-dwelling older adults with diabetes: A systematic review and meta-analysis.

AIMS: Cognitive frailty can increase the risk of adverse health outcomes in older adults. Estimates of the prevalence of cognitive frailty among older adults with diabetes varied widely in literature. This study aimed to conduct a systematic review and meta-analysis to assess the pooled prevalence of cognitive frailty and risk factors in community-dwelling older adults with diabetes, providing evidence for healthcare professionals to better understand the status of cognitive frailty and help develop effective interventions. METHODS: Databases of PubMed, Web of Science, Cochrane Library, Embase, Cumulative Index of Nursing and Allied Health, Proquest, China National Knowledge Infrastructure and China Biology Medicine were searched from inception to February 10th, 2022. The reviewers independently selected studies, extracted data and assessed the quality of studies. Pooled prevalence of cognitive frailty and risk factors were estimated. Subgroup analysis, meta-regression analysis, sensitivity analysis and publication bias were also conducted. RESULTS: A total of 15 studies with 6391 participants were included in this review. The pooled prevalence of cognitive frailty was 11% (95%CI = 7.9-14%) in community-dwelling older adults with diabetes. Pooled estimates showed that increasing age, higher level of HbA1c, shorter night sleep duration and depression were risk factors, and regular exercise was the protective factor of cognitive frailty in community-dwelling older adults with diabetes. CONCLUSION: Cognitive frailty was common in community-dwelling older adults with diabetes. Routine screening of cognitive frailty and effective interventions should be implemented for this population in community settings. REGISTRATION: PROSPERO ID CRD42021276973.

Relationship between ATOH1 and tumor microenvironment in colon adenocarcinoma patients with different microsatellite instability status.

BACKGROUND: Colon adenocarcinoma (COAD) is one of the major varieties of malignant tumors threatening human health today. Immune checkpoint inhibitors (ICIs) have recently begun to emerge as an effective option for the treatment of COAD patients, but not all patients can benefit from ICI treatment. Previous studies have suggested that ICIs boast significant clinical effects on patients with microsatellite instability-high (MSI-H), while conversely patients with microsatellite-stable/microsatellite instability-low (MSS/MSI-L) have shown limited response. METHODS: We used ATAC-seq, RNA-seq, and mutation data from The Cancer Genome Atlas Colon adenocarcinoma (TCGA-COAD) cohort to perform multi-omics differential analysis on COAD samples with different MSI statuses, then further screened genes by additionally combining these results with survival analysis. We analyzed the effects of the screened genes on the tumor microenvironment and immunogenicity of COAD patients, and subsequently determined their influence on the efficacy of ICIs in COAD patients using a series of predictive indexes. RESULTS: Twelve genes were screened in the TCGA-COAD cohort, and after the combined survival analysis, we identified ATOH1 as having significant effects. ATOH1 is characterized by high chromatin accessibility, high expression, and high mutation in COAD patients in the MSI-H group. COAD patients with high ATOH1 expression are associated with a better prognosis, unique immune microenvironment, and higher efficacy in ICI treatment. Enrichment analysis showed that COAD patients with high ATOH1 expression displayed significant upregulation in their humoral immunity and other related pathways. CONCLUSIONS: We speculate that ATOH1 may influence the efficacy of ICIs therapy in patients with COAD by affecting the immune microenvironment and immunogenicity of the tumor.

The ameliorating effects of metformin on disarrangement ongoing in gastrocnemius muscle of sarcopenic and obese sarcopenic mice.

Sarcopenia and obese sarcopenia are increasingly prevalent chronic diseases with multifactorial pathogenesis, and no approved therapeutic drug to date. In the established sarcopenic mice models, muscle weakness, ectopic lipid deposition, and inflammatory responses in both serum and gastrocnemius muscle were observed, which were even deteriorated in obese sarcopenic models. With metformin intervention for 5 months, metformin exhibited benefits and restoring effects on gastrocnemius muscle of sarcopenic mice, but less effective on that of obese sarcopenic mice, as reflected in the increased percentage of muscle mass and enlarged fiber cross-sectional area, enhanced grip strength and exercise capacities, as well as the ameliorated ectopic lipid deposition and partially restored level of TNF-α, IL-1ß, IL-6, MCP-1 and IL-1α, which may be via the activation of phospho-AMPKα (Thr172). The significant up-regulated mRNA and protein level of lipolysis related proteins like hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) may contribute to the ameliorated ectopic lipid deposition with metformin intervention. The uptake of free fatty acid may be also inhibited in obese sarcopenic mice with metformin administration, as reflected in down-regulated mRNA and protein level of fatty acid transporter CD36. Furthermore, NF-κB signaling pathway was involved in the anti-inflammatory effect of metformin. These findings suggest that metformin treatment may be conducive to the prevention of age-related sarcopenia by regulating lipid metabolism in skeletal muscle, i.e. enhanced lipolysis and attenuated hyper-inflammatory responses, which may be AMPK-dependent processes. Moreover, high-fat diet would aggravate the damage to ageing in skeletal muscles and reduced their reactivity to metformin.

CHRNA1 induces sarcopenia through neuromuscular synaptic elimination.

Sarcopenia seriously affects the quality of life of the elderly, but its molecular mechanism is still unclear. Degeneration in muscle innervation is related to age-related movement disorders and muscle atrophy. The expression of CHRNA1 is increased in the skeletal muscle of the elderly, and in aging rodents. Therefore, we investigated whether CHRNA1 induces the occurrence and development of sarcopenia. Compared with the control group, local injection of AAV9-CHRNA1 into the hindlimb muscles decreased the percentage of muscle innervation. At the same time, the skeletal muscle mass decreased, as manifested by a decrease in the gastrocnemius mass index and the cross-sectional area of the muscle fibers. The function of skeletal muscle also decreased, which was manifested by decreases of compound muscle action potential and muscle contractility. Therefore, we concluded that upregulation of CHRNA1 can induce and aggravate sarcopenia.

Applications of Machine Learning to Predict Cisplatin Resistance in Lung Cancer.

PURPOSE: Lung cancer, mainly lung adenocarcinoma, lung squamous cell carcinoma and small cell lung cancer, has the highest incidence and cancer-related mortality worldwide. Platinum-based chemotherapy plays an important role in the treatment of various lung cancer subtypes, but not all patients benefit from this treatment regimen; thus, it is worth identifying lung cancer patients who are resistant or sensitive to platinum-based therapy. METHODS: The drug response and sequencing data of 170 lung cancer cell lines were downloaded from the Genomics of Drug Sensitivity in Cancer (GDSC) database, and support vector machines (SVMs) and beam search were used to select an optimal gene panel that can predict the sensitivity of cell lines to cisplatin. Then, we used available cell line data to explore the potential mechanisms. RESULTS: In this work, the drug response and sequencing data of 170 lung cancer cell lines were downloaded from the GDSC database, and SVMs and beam search were used to screen a panel of genes related to lung cancer cell line resistance to cisplatin. A final panel of nine genes (PLXNC1, KIAA0649, SPTBN4, SLC14A2, F13A1, COL5A1, SCN2A, PLEC, and ALMS1) was identified, and achieved an area under the curve (AUC) of 0.873 ± 0.004. The natural logarithm of the half maximal inhibitory concentration (lnIC50) values of the mutant-type (panel-MT) group was significantly higher than that of the wild-type (panel-WT) group, regardless of the lung cancer subtype. The differentially expressed pathways between the two groups may explain this difference. CONCLUSION: In this study, we found that a panel of nine genes can accurately predict sensitivity to cisplatin, which may provide individualized treatment recommendations to improve the prognosis of patients with lung cancer.

High mutations in fatty acid metabolism contribute to a better prognosis of small-cell lung cancer patients treated with chemotherapy.

BACKGROUND: The majority of patients with small-cell lung cancer (SCLC) show a good response in the early stages of treatment, but more than 90% of patients will develop drug resistance. Therefore, biomarkers are urgently needed to identify patients who can benefit from systemic treatment. METHODS: We prospectively enrolled 52 extensive-stage SCLC patients before treatment from a local hospital to identify mutations related to patient prognosis, and verified them in the published Jiang's cohort and George's cohort. RESULTS: We found that patients with high mutations (mut-high) in the fatty acid (FA) metabolism pathway had a longer progression-free survival (PFS) in the local hospital cohort (HR = 0.446, 95% CI, 0.207-0.959, p = 0.0387) and a longer overall survival (OS) in Jiang's cohort (HR = 0.549, 95% CI, 0.314-0.960, p = 0.0351) than patients with low mutations (mut-low). Multivariate analysis suggested that mut-high status was an independent prognostic factor in both cohorts. George's cohort verified that mut-high status was associated with a longer OS than mut-low status (HR = 0.730, 95% CI 0.440-1.220, p = 0.2277). The possible mechanisms were as follows: the frequency of mutated FA synthase (FASN) in the mut-high group was greater than that in the mut-low group, and pathways related to the cell cycle, DNA repair, and oxidative phosphorylation were enriched in the mut-high group. CONCLUSIONS: The prognosis of SCLC patients treated with chemotherapy was better among patients with more mutations in the FA metabolism pathway, and the underlying mechanisms could be found at the genome and transcriptome levels.

Causal Effect of Blood Pressure on Bone Mineral Density and Fracture: A Mendelian Randomization Study.

Background: Hypertension may have some association with osteoporosis. This Mendelian randomization (MR) study aimed to explore the causal effect of blood pressure (BP) on bone mineral density (BMD), fall, and fracture. Methods: We used the genome-wide association study (GWAS) summary data among 330,956 European-descent individuals to identify 107 single-nucleotide polymorphisms (SNPs) as the instrumental variables of BP. MR analyses of these instruments were performed on 53,236 European individuals for the association with forearm BMD (FA-BMD), femoral neck BMD (FN-BMD), and lumbar spine BMD (LS-BMD); 451,179 European individuals for fall susceptibility; and up to 1.2 million individuals from European descent for fracture. Conventional inverse variance weighted (IVW) method was adopted to obtain the causal estimates of BP on different outcomes, while weighted median, MR-egger, and MR pleiotropy residual sum and outlier (MR-PRESSO) test were used for sensitivity analyses. Results: Genetically high pulse pressure (PP) could significantly improve FA-BMD (beta-estimate: 0.038, 95% confidence interval [CI]: 0.013 to 0.063, SE:0.013, P-value=0.003

Influence of Different Age Cutoff Points on the Prediction of Prognosis of Cancer Patients Receiving ICIs and Potential Mechanistic Exploration.

Age is a potential predictive marker for the prognosis of cancer patients treated with immune checkpoint inhibitors (ICIs), but the appropriate age cutoff point is still controversial. We aimed to explore the influence of different age cutoff points on the prediction of prognosis for patients receiving ICIs and explore the mechanism underlying the appropriate age cutoff point from the aspects of gene mutation and expression, immune cell infiltration and so on. We applied cutoff points of 50, 55, 60, 65, 70, and 75 years old to divide 1660 patients from the Memorial Sloan-Kettering Cancer Center (MSKCC) immunotherapy cohort into older and younger groups and performed survival analysis of the six subgroups. The results showed that older patients had better survival than younger patients in accordance with the cutoff point of 50 years old [median overall survival (OS) (95% CI): 13.0 (10.5-15.5) months vs. 20.0 (16.7-23.3) months; p=0.002; unadjusted hazard ratio (HR) (95% CI): 0.77 (0.65-0.91)], whereas no significant difference was observed with other cutoff points. Further analysis of The Cancer Genome Atlas (TCGA) database and the MSKCC immunotherapy cohort data showed that the tumor mutation burden (TMB), neoantigen load (NAL), DNA damage response and repair (DDR) pathway mutation status, mutation frequencies of most genes (except IDH1, BRAF and ATRX), the expression of most immune-related genes and the degree of infiltration of most immune cells (such as CD8+ T cells and M1 macrophages) were higher in the elderly group (aged ≥50 years).

Depression and Osteoporosis: A Mendelian Randomization Study.

Observational studies suggest a link between depression and osteoporosis, but these may be subject to confounding and reverse causality. In this two-sample Mendelian randomization analysis, we included the large meta-analysis of genome-wide association studies for depression among 807,553 individuals (246,363 cases and 561,190 controls) of European descent, the large meta-analysis to identify genetic variants associated with femoral neck bone mineral density (FN-BMD), forearm BMD (FA-BMD) and lumbar spine BMD (LS-BMD) among 53,236 individuals of European ancestry, and the GWAS summary data of heel BMD (HE-BMD) and fracture among 426,824 individuals of European ancestry. The results revealed that genetic predisposition towards depression showed no causal effect on FA-BMD (beta-estimate: 0.091, 95% confidence interval [CI] - 0.088 to 0.269, SE:0.091, P value = 0.320), FN-BMD (beta-estimate: 0.066, 95% CI - 0.016 to 0.148, SE:0.042, P value = 0.113), LS-BMD (beta-estimate: 0.074, 95% CI - 0.029 to 0.177, SE:0.052, P value = 0.159), HE-BMD (beta-estimate: 0.009, 95% CI - 0.043 to 0.061, SE:0.027, P value = 0.727), or fracture (beta-estimate: 0.008, 95% CI - 0.071 to 0.087, SE:0.041, P value = 0.844). These results were also confirmed by multiple sensitivity analyses. Contrary to the findings of observational studies, our results do not reveal a causal role of depression in osteoporosis or fracture.

The prevalence of frailty among community-dwelling older adults with diabetes: A meta-analysis.

BACKGROUND: Coexistence of frailty and chronic diseases including diabetes is related to a higher risk of adverse health outcomes. There is an increasing interest in the intersection of diabetes and frailty. Understanding the prevalence of frailty in older adults with diabetes is of great importance. However, estimates of the prevalence of frailty among this population varied widely in the relevant literature. OBJECTIVES: To conduct a systematic review and meta-analysis to estimate the overall prevalence of frailty and prefrailty among community-dwelling older adults with diabetes, and examine the risk factors associated with frailty in this population. METHODS: PubMed, Web of Science, Embase, Wiley Cochrane Library, and Cumulative Index of Nursing and Allied Health were searched from inception to May 30th, 2020. Investigators assessed eligibility, extracted data and evaluated methodological quality. The pooled prevalence of frailty and prefrailty was calculated using the random-effects model. Meta-regression analysis and subgroup analysis were conducted to explore sources of heterogeneity. RESULTS: A total of 32 studies met the inclusion criteria, involving 14,450 individuals. The pooled prevalence of frailty and prefrailty in older adults with diabetes was 20.1% (95% CI = 16.0-24.2%) and 49.1% (95%CI = 45.1-53.1%), respectively, with significant heterogeneity across the studies. Frailty was more prevalent in older adults with diabetes than those without diabetes (OR = 1.61, 95%CI = 1.47-1.77, p < 0.001). The pooled prevalence of frailty was lower in studies using Frailty Phenotype to define frailty (16.3%) and conducted in Asia (14.3%). Female gender and unmarried status were risk factors of frailty among this population. CONCLUSION: Frailty and prefrailty are common in community-dwelling older adults with diabetes. Early screening of frailty and interventions should be integrated into diabetes care for older adults to prevent and reduce the negative effects of frailty at the community level. Better quality longitudinal research is required to examine the temporal relationship between diabetes and frailty.

Multi-omics reveals age-related differences in the diaphragm response to mechanical ventilation: a pilot study.

BACKGROUND: Old age is associated with a significantly increased mortality in COVID-19 patients exposed to long-term controlled mechanical ventilation (CMV) and suggested to be due to the hyperinflammatory response associated with the viral infection. However, our understanding of age-related differences in the response to CMV in the absence of a viral infection remains insufficient. METHODS: Young (7-8 months) and old (28-32 months) F344 BN hybrid rats were exposed to the ICU condition for 5 days, i.e., complete immobilization, mechanical ventilation, and extensive monitoring. Transcriptomic (RNA-Seq) and proteomics (Proximity Extension Assay) analyses of the diaphragm and proteomics analysis of plasma were conducted to investigate the molecular differences between young and old rats exposed to the ICU condition. RESULTS: According to multi-omics analyses, significant differences were observed in the diaphragm between young and old rats in response to 5 days CMV and immobilization. In young rats, metabolic pathways were primarily downregulated in response to immobilization (post-synaptic blockade of neuromuscular transmission). In old rats, on the other hand, dramatic immune and inflammatory responses were observed, i.e., an upregulation of specific related pathways such as "IL-17 signaling pathway", along with a higher level of inflammatory factors and cytokine/chemokine in plasma. CONCLUSIONS: The dramatically increased mortality in old ICU patients with COVID-19-associated hyperinflammation and cytokine storm need not only reflect the viral infection but may also be associated with the ventilator induced diaphragm dysfunction (VIDD) and hyperinflammatory responses induced by long-term CMV per se. Although mechanical ventilation is a life-saving intervention in COVID-19 ICU patients, CMV should be cautiously used especially in old age and other means of respiratory support may be considered, such as negative pressure ventilation.

Alterations in TP53 Are a Potential Biomarker of Bladder Cancer Patients Who Benefit From Immune Checkpoint Inhibition.

In recent years, immune checkpoint inhibitors (ICIs) targeting CTLA-4 or PD1/PDL1 have achieved remarkable success in the treatment of bladder cancer (BLCA), but only a few patients have shown durable clinical benefits. The prognostic role of a mutant form of the tumor suppressor gene TP53 (TP53-MT) in predicting the efficacy of ICIs is highly controversial; therefore, in this study, we obtained data for 210 patients from an immunotherapy cohort, 412 patients from The Cancer Genome Atlas (TCGA)-BLCA cohort and 18 BLCA cell lines from Genomics of Drug Sensitivity in Cancer (GDSC), and we performed integrated bioinformatic analysis to explore the relationships between TP53-MT and clinical benefits derived from ICI treatment and the underlying mechanisms. We conclude that TP53-MT is a potential indicator of a relatively good response to ICIs and associated with prolonged overall survival (OS) (log-rank test, hazard ratio (HR) = 0.65 [95% confidence interval (CI), 0.44-0.99], p = 0.041). Through integrated analysis with several platforms, we found that TP53-MT patients were more likely to benefit from ICIs than wild-type P53 (TP53-WT) patients, which may be the result of 2 major mechanisms. First, the patients with TP53-MT showed stronger tumor antigenicity and tumor antigen presentation, as indicated by a higher tumor mutational load, a higher neoantigen load and increased expression of MHC; second, the antitumor immunity preexisting in tumors was stronger in samples with TP53-MT than in those with TP53-WT, including enrichment of interferon-gamma, positive regulation of TNF secretion pathways and increased expression of some immunostimulatory molecules, such as CXCL9 and CXCL10. This study provided some clues for identifying patients who would potentially benefit from ICIs at the somatic genomic level, developing new indications for targeted second-generation sequencing and promoting the development of precision medicine.

Type 2 diabetes-induced overactivation of P300 contributes to skeletal muscle atrophy by inhibiting autophagic flux.

AIMS: Although autophagy impairment is a well-established cause of muscle atrophy and P300 has recently been identified as an important regulator of autophagy, the effects of P300 on autophagy and muscle atrophy in type 2 diabetes (T2D) remain unexplored. We aimed at characterizing the role of P300 in diabetic muscle and its underlying mechanism. MAIN METHODS: Protein levels of phosphorylated P300, total P300, acetylated histone H3, LC3, p62 and myosin heavy chain, and mRNA levels of Atrogin-1 and MuRF1 were analyzed in palmitic acid (PA)-treated myotubes and db/db mice. Autophagic flux was assessed using transmission electron microscopy, immunofluorescence and mRFP-GFP-LC3 lentivirus transfection in cells. Muscle weight, blood glucose and grip strength were measured in mice. Hematoxylin and eosin (H&E) staining was performed to determine changes in muscle fiber size. To investigate the effects of P300 on autophagy and myofiber remodeling, a P300 specific inhibitor, c646, was utilized. 3-Methyladenine (3-MA) was utilized to inhibit autophagosomes formation, and chloroquine (CQ) was used to block autophagic flux. KEY FINDINGS: Phosphorylation of P300 in response to PA enhanced its activity and subsequently suppressed autophagic flux, leading to atrophy-related morphological and molecular changes in myotubes. Inhibition of P300 reestablished autophagic flux and ameliorated PA-induced myotubes atrophy. However, this effect was largely abolished by co-treatment with the autophagy inhibitor CQ. In vivo results demonstrated that inhibition of P300 partially rescued muscle wasting in db/db mice, accompanied with autophagy reactivation. SIGNIFICANCE: The findings revealed that T2D-induced overactivation of P300 contributes to muscle atrophy by blocking autophagic flux.

Inhibition of TLR9 attenuates skeletal muscle fibrosis in aged sarcopenic mice via the p53/SIRT1 pathway.

Sarcopenia is an age-related syndrome characterized by a gradual loss of muscle mass and function, but its pathophysiological mechanism remains unclear. Skeletal muscle extracellular matrix (ECM) remodeling is an important pathological change in sarcopenia, and fibrosis is the most obvious manifestation of this change. We found that the expression of the immunoreceptor Toll-like receptor 9 (TLR9) is significantly increased in skeletal muscle in aged mice and is positively related to muscle fibrosis. Moreover, in previous reports, the longevity gene Sirt1 was reported to attenuate ECM deposition and improve muscle function. In this study, we hypothesized that TLR9 modulated skeletal muscle fibrosis via Sirt1. We used TLR9 knockout (TLR9 KO) mice and C57 mice, and grip strength and body composition were compared at different ages. We found that TLR9 knockout significantly attenuated skeletal muscle fibrosis and improved muscle function in aged mice. Furthermore, silent information regulator 1 (Sirt1) activity in mice was inhibited by Ex527, which is a specific inhibitor of Sirt1. Negative Sirt1 regulation via the activation of TLR9-related signaling pathways participated in skeletal muscle fibrosis in the sarcopenic mice, and this process might mediated by the Sirt1/Smad signaling pathway. Our findings revealed that fibrosis changes in the gastrocnemius muscle in sarcopenic mice are closely related to TLR9 activation, and TLR9 modulation could be a therapeutic strategy for combating sarcopenia during aging.