Multifunctions of CRIF1 in cancers and mitochondrial dysfunction

GADD45A: With or without you

The growth arrest and DNA damage inducible (GADD)45 family includes three small and ubiquitously distributed proteins (GADD45A, GADD45B, and GADD45G) that regulate numerous cellular processes associated with stress signaling and injury response. Here, we provide a comprehensive review of the current literature investigating GADD45A, the first discovered member of the family. We first depict how its levels are regulated by a myriad of genotoxic and non-genotoxic stressors, and through the combined action of intricate transcriptional, posttranscriptional, and even, posttranslational mechanisms. GADD45A is a recognized tumor suppressor and, for this reason, we next summarize its role in cancer, as well as the different mechanisms by which it regulates cell cycle, DNA repair, and apoptosis. Beyond these most well-known actions, GADD45A may also influence catabolic and anabolic pathways in the liver, adipose tissue and skeletal muscle, among others. Not surprisingly, GADD45A may trigger AMP-activated protein kinase activity, a master regulator of metabolism, and is known to act as a transcriptional coregulator of numerous nuclear receptors. GADD45A has also been reported to display a cytoprotective role by regulating inflammation, fibrosis and oxidative stress in several organs and tissues, and is regarded an important contributor for the development of heart failure. Overall data point to that GADD45A may play an important role in metabolic, neurodegenerative and cardiovascular diseases, and also autoimmune-related disorders. Thus, the potential mechanisms by which dysregulation of GADD45A activity may contribute to the progression of these diseases are also reviewed below.

Human and Murine Toll-like Receptor-Driven Disease in Systemic Lupus Erythematosus

The pathogenesis of systemic lupus erythematosus (SLE) is linked to the differential roles of toll-like receptors (TLRs), particularly TLR7, TLR8, and TLR9. TLR7 overexpression or gene duplication, as seen with the Y-linked autoimmune accelerator (Yaa) locus or TLR7 agonist imiquimod, correlates with increased SLE severity, and specific TLR7 polymorphisms and gain-of-function variants are associated with enhanced SLE susceptibility and severity. In addition, the X-chromosome location of TLR7 and its escape from X-chromosome inactivation provide a genetic basis for female predominance in SLE. The absence of TLR8 and TLR9 have been shown to exacerbate the detrimental effects of TLR7, leading to upregulated TLR7 activity and increased disease severity in mouse models of SLE. The regulatory functions of TLR8 and TLR9 have been proposed to involve competition for the endosomal trafficking chaperone UNC93B1. However, recent evidence implies more direct, regulatory functions of TLR9 on TLR7 activity. The association between age-associated B cells (ABCs) and autoantibody production positions these cells as potential targets for treatment in SLE, but the lack of specific markers necessitates further research for precise therapeutic intervention. Therapeutically, targeting TLRs is a promising strategy for SLE treatment, with drugs like hydroxychloroquine already in clinical use.

CRIF1 attenuates doxorubicin-mediated mitochondrial dysfunction and myocardial senescence via regulating PXDN

BACKGROUND

CR6-interacting factor 1 (CRIF1), a multifunctional protein that affects mitochondrial function and cell senescence, plays a regulatory role in heart-related diseases. However, whether CRIF1 participates in myocardial senescence by regulating mitochondrial function remains unclear.

METHODS

Doxorubicin (DOX)-induced C57BL/6 mice to construct mouse myocardial senescence model, and the myocardial function indicators including lactate dehydrogenase (LDH) and Creatine kinase isoform MB (CK-MB) were assessed. The expression of CRIF1 was detected by western blot. Myocardial pathological changes were examined by transthoracic echocardiography and haematoxylin and eosin (H&E) staining. Cell senescence was detected by SA-β-gal staining. JC-1 staining was used to detect mitochondrial membrane potential. Biochemical kits were used to examine oxidative stress-related factors. Additionally, AC16 cardiomyocytes were treated with DOX to mimic the cellular senescence model in vitro. Cell activity was detected by cell counting kit-8 (CCK-8) assay. Co-immunoprecipitation (CO-IP) was used to verify the relationship between CRIF1 and peroxidasin (PXDN).

RESULTS

The CRIF1 expression was significantly decreased in DOX-induced senescent mice and AC16 cells. Overexpression of CRIF1 significantly ameliorated DOX-induced myocardial dysfunction and myocardial senescence. Additionally, CRIF1 overexpression attenuated DOX-induced oxidative stress and myocardial mitochondrial dysfunction. Consistently, CRIF1 overexpression also inhibited DOX-induced oxidative stress and senescence in AC16 cells. Moreover, CRIF1 was verified to bind to PXDN and inhibited PXDN expression. The inhibitory effects of CRIF1 overexpression on DOX-induced oxidative stress and senescence in AC16 cells were partly abolished by PXDN expression.

CONCLUSIONS

CRIF1 plays a protective role against DOX-caused mitochondrial dysfunction and myocardial senescence partly through downregulating PXDN.

Unlocking the potential of T-cell metabolism reprogramming: Advancing single-cell approaches for precision immunotherapy in tumour immunity

As single-cell RNA sequencing enables the detailed clustering of T-cell subpopulations and facilitates the analysis of T-cell metabolic states and metabolite dynamics, it has gained prominence as the preferred tool for understanding heterogeneous cellular metabolism. Furthermore, the synergistic or inhibitory effects of various metabolic pathways within T cells in the tumour microenvironment are coordinated, and increased activity of specific metabolic pathways generally corresponds to increased functional activity, leading to diverse T-cell behaviours related to the effects of tumour immune cells, which shows the potential of tumour-specific T cells to induce persistent immune responses. A holistic understanding of how metabolic heterogeneity governs the immune function of specific T-cell subsets is key to obtaining field-level insights into immunometabolism. Therefore, exploring the mechanisms underlying the interplay between T-cell metabolism and immune functions will pave the way for precise immunotherapy approaches in the future, which will empower us to explore new methods for combating tumours with enhanced efficacy.