Canonical Inflammasomes

Vitexin mitigates AIM2 inflammasome-mediated mitochondrial dysfunction and neuroinflammation in chronic constriction injury induced neuropathy model

The chronic constriction injury (CCI) replicates trauma-induced peripheral neuropathy by increasing oxidative-nitrosative stress, inflammation and mitochondrial dysfunction through compression of the peripheral nerves. Vitexin, a natural flavonoid was investigated for its effect on mitochondrial dysfunction -induced AIM2 inflammasome activation in CCI induced neuropathic pain in rats. The study was conducted through in vitro and in-vivo methods through vitexin treatment to LPS (1.5 μg/mL) exposed SHSY5Y cells as well as over CCI induced SD rats (3 mg/kg/day and 6 mg/kg/day, i.p.,14 days) Neuropathic pain was assessed through several behavioral evaluations. For understating the molecular mechanism, we investigated the impact of vitexin on oxidative stress, mitochondrial dysfunction, and molecular protein expressions. Our studies showed altered behaviour and functional parameters, including hyperalgesia, allodynia, damaged sciatic functions as well as increased oxidative stress, and activation of inflammasomes such as ASC, NF-κB, AIM2, and caspase 1. Furthermore, the expression of SIRT1, SIRT3, PGC-1α, and TFAM was reduced, indicating mitochondrial dysfunction. Treatment with vitexin prevented behavioral hypersensitivity, improved sciatic functions, decreased oxidative stress and inhibited AIM2 associated other inflammasome activation and mitochondrial dysfunction both in-vitro and in-vivo. Vitexin, showed neuroprotective potential by ameliorating mitochondrial dysfunction, and associated AIM2 inflammasome activation in experimental trauma induced neuropathic pain. This research offers a detailed understanding of the mechanisms involved in pathophysiology of CCI induced neuropathic pain and suggest that targeting mitochondrial dysfunction and AIM2 inflammasome may be beneficial in the management of neuropathic pain.

Mechanism of secondary renal injury in traumatic hemorrhagic shock model under a dry and heat desert environment

We established a swine model of traumatic hemorrhagic shock to assess secondary renal injury under dry-heat conditions to clarify the roles of cell pyroptosis and inflammatory response in traumatic hemorrhagic shock development. Sixty-eight domestic Landrace piglets were divided into normothermic environment, dry-heat sham surgery, and dry-heat environment traumatic hemorrhagic shock groups (four subgroups: 3 h of environmental exposure and 60, 120, and 180 min after inducing traumatic hemorrhagic shock). The kidneys and blood were sampled at various time points. Univariate analysis of variance or non-parametric test was used for intergroup and intragroup comparisons, and the least significant difference test was used for multiple comparisons. The serum lipopolysaccharide, neutrophil gelatinase-associated lipocalin, kidney injury molecule 1, blood urea nitrogen, and creatinine levels, as well as various inflammatory factors, oxidative stress indicators, and Paller score, were significantly higher under dry-heat environment traumatic hemorrhagic shock than under normothermic environment and dry-heat sham surgery at 180 min. The histopathological damage in the dry-heat environment traumatic hemorrhagic shock group increased significantly at 180 min. Immunohistochemistry, western blotting, and terminal deoxynucleotidyl transferase dUTP nick end labeling assays showed that protein expression and apoptosis index values in the renal tissues of all three groups increased but were significantly higher under dry-heat environment traumatic hemorrhagic shock than under normothermic environment and dry-heat sham surgery at 180 min. The combination of dry-heat environment and traumatic hemorrhagic shock induces an aggravation of secondary renal injury, which may be related to cell pyroptosis, inflammatory response, apoptosis, and oxidative stress. Our findings may assist in the development of treatments for acute kidney injury.

Mitochondrial DAMPs: Key mediators in neuroinflammation and neurodegenerative disease pathogenesis

Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS) are increasingly linked to mitochondrial dysfunction and neuroinflammation. Central to this link are mitochondrial damage-associated molecular patterns (mtDAMPs), including mitochondrial DNA, ATP, and reactive oxygen species, released during mitochondrial stress or damage. These mtDAMPs activate inflammatory pathways, such as the NLRP3 inflammasome and cGAS-STING, contributing to the progression of neurodegenerative diseases. This review delves into the mechanisms by which mtDAMPs drive neuroinflammation and discusses potential therapeutic strategies targeting these pathways to mitigate neurodegeneration. Additionally, it explores the cross-talk between mitochondria and the immune system, highlighting the complex interplay that exacerbates neuronal damage. Understanding the role of mtDAMPs could pave the way for novel treatments aimed at modulating neuroinflammation and slowing disease progression, ultimately improving patient outcome.

Inflammation unleashed: The role of pyroptosis in chronic liver diseases

Pyroptosis, a newly identified form of programmed cell death intertwined with inflammatory responses, is facilitated by the Gasdermin family's pore-forming activity, leading to cell lysis and the release of pro-inflammatory cytokines. This process is a double-edged sword in innate immunity, offering protection against pathogens while risking excessive inflammation and tissue damage when dysregulated. Specifically, pyroptosis operates through two distinct signaling pathways, namely the Caspase-1 pathway and the Caspase-4/5/11 pathway. In the context of chronic liver diseases like fibrosis and cirrhosis, inflammation emerges as a central contributing factor to their pathogenesis. The identification of inflammation is characterized by the activation of innate immune cells and the secretion of pro-inflammatory cytokines such as IL-1α, IL-1β, and TNF-α. This review explores the interrelationship between pyroptosis and the inflammasome, a protein complex located in liver cells that recognizes danger signals and initiates Caspase-1 activation, resulting in the secretion of IL-1β and IL-18. The article delves into the influence of the inflammasome and pyroptosis on various liver disorders, with a specific focus on their molecular and pathophysiological mechanisms. Additionally, the potential therapeutic implications of targeting pyroptosis for liver diseases are highlighted for future consideration.

Vaginal microbes alter epithelial transcriptome and induce epigenomic modifications providing insight into mechanisms for susceptibility to adverse reproductive outcomes

The cervicovaginal microbiome is highly associated with women's health, with microbial communities dominated by Lactobacillus species considered optimal. Conversely, a lack of lactobacilli and a high abundance of strict and facultative anaerobes, including Gardnerella vaginalis, have been associated with adverse reproductive outcomes. However, how host-microbial interactions alter specific molecular pathways and impact cervical and vaginal epithelial function remains unclear. Using RNA-sequencing, we characterized the in vitro cervicovaginal epithelial transcriptional response to different vaginal bacteria and their culture supernatants. We showed that G. vaginalis upregulates genes associated with an activated innate immune response. Unexpectedly, G. vaginalis specifically induced inflammasome pathways through activation of NLRP3-mediated increases in caspase-1, IL-1β and cell death, while live L. crispatus had minimal transcriptomic changes on epithelial cells. L. crispatus culture supernatants resulted in a shift in the epigenomic landscape of cervical epithelial cells that was confirmed by ATAC-sequencing showing reduced chromatin accessibility. This study reveals new insights into host-microbe interactions in the lower reproductive tract and suggests potential therapeutic strategies leveraging the vaginal microbiome to improve reproductive health.

NLRP inflammasomes in health and disease

NLRP inflammasomes are a group of cytosolic multiprotein oligomer pattern recognition receptors (PRRs) involved in the recognition of pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) produced by infected cells. They regulate innate immunity by triggering a protective inflammatory response. However, despite their protective role, aberrant NLPR inflammasome activation and gain-of-function mutations in NLRP sensor proteins are involved in occurrence and enhancement of non-communicating autoimmune, auto-inflammatory, and neurodegenerative diseases. In the last few years, significant advances have been achieved in the understanding of the NLRP inflammasome physiological functions and their molecular mechanisms of activation, as well as therapeutics that target NLRP inflammasome activity in inflammatory diseases. Here, we provide the latest research progress on NLRP inflammasomes, including NLRP1, CARD8, NLRP3, NLRP6, NLRP7, NLRP2, NLRP9, NLRP10, and NLRP12 regarding their structural and assembling features, signaling transduction and molecular activation mechanisms. Importantly, we highlight the mechanisms associated with NLRP inflammasome dysregulation involved in numerous human auto-inflammatory, autoimmune, and neurodegenerative diseases. Overall, we summarize the latest discoveries in NLRP biology, their forming inflammasomes, and their role in health and diseases, and provide therapeutic strategies and perspectives for future studies about NLRP inflammasomes.