Extracellular Prdx1 mediates bacterial infection and inflammatory bone diseases

Panoptosis Targets the Mechanism of PRDX1 Involvement in Acute Myocardial Infarction via ZBP1

PANoptosis is involved in various pathological processes, but its role in acute myocardial infarction (AMI) remains unclear. This study aimed to explore the mechanism by which PANoptosis is involved in AMI. GSE172270 was used as an internal test set, and GSE159657 served as an external validation set to identify disease targets for AMI. WGCNA was performed to identify potential hub genes associated with AMI. Then, genes related to PANoptosis among the disease targets of AMI were screened. Additionally, human cardiomyocytes AC16 and mouse cardiomyocytes HL-1 were cultured in sugar-free and serum-free medium for 4 h and 12 h, and the expression of key genes regulating PANoptosis was detected by qRT-PCR. Finally, mRNA interference and overexpression experiments were conducted to verify the expression of key mRNAs. A total of 45 upregulated and 125 downregulated differentially expressed genes (DEGs) were identified in the GSE172270 data set. WGCNA identified 891 potential hub genes associated with AMI. In the GSE159657 data set, 695 upregulated and 552 downregulated DEGs were identified. Four genes related to AMI-PANoptosis (PRDX1, MMACHC, BLVRB, and TXNL1) were screened. Through qRT-PCR verification, PRDX1 was identified as the most specific and significant gene. The expression of the PANoptosis positive regulator ZPB1 was upregulated, while the PANoptosis negative regulator TAK1 was downregulated. Additionally, key cell death genes (MLKL, p-MLKL, Caspase-3, Caspase-7, and GSDMD) were upregulated in sugar-free and serum-free culture. However, PRDX1 interference reversed these effects. Our study demonstrated that PRDX1 is a key regulator of PANoptosis in AMI.

The intricate interactions between inflammasomes and bacterial pathogens: Roles, mechanisms, and therapeutic potentials

Inflammasomes are intracellular multiprotein complexes that consist of a sensor, an adaptor, and a caspase enzyme to cleave interleukin (IL)-1β and IL-18 into their mature forms. In addition, caspase-1 and -11 activation results in the cleavage of gasdermin D to form pores, thereby inducing pyroptosis. Activation of the inflammasome and pyroptosis promotes host defense against pathogens, whereas dysregulation of the inflammasome can result in various pathologies. Inflammasomes exhibit versatile microbial signal detection, directly or indirectly, through cellular processes, such as ion fluctuations, reactive oxygen species generation, and the disruption of intracellular organelle function; however, bacteria have adaptive strategies to manipulate the inflammasome by altering microbe-associated molecular patterns, intercepting innate pathways with secreted effectors, and attenuating inflammatory and cell death responses. In this review, we summarize recent advances in the diverse roles of the inflammasome during bacterial infections and discuss how bacteria exploit inflammasome pathways to establish infections or persistence. In addition, we highlight the therapeutic potential of harnessing bacterial immune subversion strategies against acute and chronic bacterial infections. A more comprehensive understanding of the significance of inflammasomes in immunity and their intricate roles in the battle between bacterial pathogens and hosts will lead to the development of innovative strategies to address emerging threats posed by the expansion of drug-resistant bacterial infections.

Therapeutic effect of bloodletting on bone deterioration induced by hypobaric hypoxia in young rats

OBJECTIVES

High-altitude regions, comprising hypoxic condition, are associated with different altitude-induced pathologies, including a reduction in bone density. Elucidating the mechanisms underlying bone degradation in such environments and developing targeted interventions and therapeutics is important. Bloodletting therapy has promising clinical applications, but its effects on the skeletal system and bone homeostasis are not well understood. The aim of this study was to investigate the effects of a hypobaric hypoxia environment on specific femoral morphological and structural properties, including the bone volume, cortical thickness, and trabecular microarchitecture, in juvenile Sprague-Dawley (SD) rats, and to explore the potential modulating effects of a bloodletting intervention on these parameters.

METHODS

Male SD rats, 6 weeks of age, were subjected to a simulated hypobaric hypoxia environment, replicating a 5000-m altitude, for 12 weeks. For the bloodletting intervention group, rats were subjected to a weekly 500 μL tail vein blood withdrawal. Micro-CT technology, hematoxylin and eosin staining, and tartrate-resistant acid phosphatase staining were employed to comprehensively assess the femoral microstructure, tissue architecture, and cellular morphology. Additionally, immunofluorescence analysis was conducted to quantify the expression of key proteins, and transcriptome analysis was performed to identify differentially expressed genes.

RESULTS

Exposing rats to hypobaric hypoxia led to a significant reduction in the bone mineral content, trabecular bone number, and cortical bone thickness, suggesting a deterioration of bone microstructure. Additionally, the hypoxic environment upregulated the expression of RANKL and HIF-1α, while downregulating RUNX2 expression. Notably, although bloodletting intervention did not significantly reverse these bone structural changes, transcriptome analysis revealed its regulatory influence on the expression of key genes, particularly Mmp2, Fosl2, and URS0000B2A65A, which are implicated in pathways governing the hypoxic response, osteoclast differentiation, and PI3K-Akt signaling.

CONCLUSION

This study highlights the detrimental effect of hypobaric hypoxia on the bone microstructure of juvenile rats and underscores the therapeutic potential of bloodletting to ameliorate this condition. Additionally, our study on the regulatory mechanisms mediating the effects of bloodletting on gene expression offers new perspectives on bone alterations. It suggests promising avenues for the development of novel preventative measures and targeted therapies to address the challenges posed by related bone disorders.

Roles of the Caspase-11 Non-Canonical Inflammasome in Rheumatic Diseases

Inflammasomes are intracellular multiprotein complexes that activate inflammatory signaling pathways. Inflammasomes comprise two major classes: canonical inflammasomes, which were discovered first and are activated in response to a variety of pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), and non-canonical inflammasomes, which were discovered recently and are only activated in response to intracellular lipopolysaccharide (LPS). Although a larger number of studies have successfully demonstrated that canonical inflammasomes, particularly the NLRP3 inflammasome, play roles in various rheumatic diseases, including rheumatoid arthritis (RA), infectious arthritis (IR), gouty arthritis (GA), osteoarthritis (OA), systemic lupus erythematosus (SLE), psoriatic arthritis (PA), ankylosing spondylitis (AS), and Sjögren's syndrome (SjS), the regulatory roles of non-canonical inflammasomes, such as mouse caspase-11 and human caspase-4 non-canonical inflammasomes, in these diseases are still largely unknown. Interestingly, an increasing number of studies have reported possible roles for non-canonical inflammasomes in the pathogenesis of various mouse models of rheumatic disease. This review comprehensively summarizes and discusses recent emerging studies demonstrating the regulatory roles of non-canonical inflammasomes, particularly focusing on the caspase-11 non-canonical inflammasome, in the pathogenesis and progression of various types of rheumatic diseases and provides new insights into strategies for developing potential therapeutics to prevent and treat rheumatic diseases as well as associated diseases by targeting non-canonical inflammasomes.