Role of inflammasomes/pyroptosis and PANoptosis during fungal infection

Combination of bulk RNA and single-cell sequencing unveils PANoptosis-related immunological ecology hallmarks and classification for clinical decision-making in hepatocellular carcinoma

PANoptosis is engaged in the program of immune response and carcinogenicity. Nonetheless, the actual impacts of PANoptosis on clinical management and oncology immunity in hepatocellular carcinoma (HCC) are not fully grasped. RNA-seq-derived computations were conducted to sort out the molecular subtypes and elucidate the disparities based on PANoptosis molecules. Single-cell sequencing (scRNA-seq) tools including Cytotrace and Addmodulescore were extracted to characterize diversification potency and quantify the PANoptosis motion. Transcriptional factors were inferred by the pySCENIC package and Cellchat program scrutinized the intercellular exchange across cell compartments. The PANoptosis score system originated by incorporating 10 machine learning algorithms and 101 compositions to project clinical results and deteriorate tendencies. Circulatory PANoptosis-associated protein HSP90AA1 was determined by enzyme-linked immunosorbent assay (ELISA). HCC individuals could be categorized into low- and high-PANoptosis groups with diverse biogenic and pharmacotherapy heterogeneity. Individuals in the elevated PANoptosis subtype were characterized as "hot tumor" conveying the increased presence of immunogenicity while reiterating an explicit negative connection with tumor stemness. Compared to immune and stromal cells, cancerous cells showcased decreased PANoptosis and heightened PANoptosis malignant cell subgroups might be tied to a substantial level of genomic expression of SREBF2, JUND, GATAD1, ZBTB20, SMAD5 and implied a more aggressive potential. The PANoptosis index, derived from machine learning, has been established to provide succinct frameworks for predicting outcomes and clarified the noteworthy utility of conventional regimens, as the differentiated power of HCC occurred together with vascular invasion and hepatocellular adenoma (HCA). The experiment confirmed that the circulating HSP90AA1 was aberrantly augmented in HCC patients, thus demonstrating its potential as a discriminatory biomarker. We systematically deciphered the molecular and immune ecosystem traits of PANoptosis in bulk and scRNA-seq degrees, which may deliver advantageous insights for customized treatment, awareness of the pathological process and prognosis scrutiny for HCC patients.

Zinc oxide nanoparticles disrupt the mammary epithelial barrier via Z-DNA binding protein 1-triggered PANoptosis

Lactation women, a highly concerned demographic in society, face health risks that deserve attention. Zinc oxide nanoparticles (ZnO NPs) are widely utilized in food and daily products due to their excellent physicochemical properties, leading to the potential exposure of lactating women to ZnO NPs. Hence, assessing the potential risks associated with ZnO NP exposure during lactation is critical. While studies have confirmed that exposure to ZnO NPs during lactation can induce toxic responses in multiple organs through blood circulation, the effects of lactational exposure on mammary tissue remain unclear. This research investigated the impairment of mammary tissue induced by ZnO NPs and its potential mechanisms. Through administering multiple injections of ZnO NPs into the tail vein of lactating ICR mice, our study revealed that ZnO NPs can deposit in the mammary tissues, downregulating key components of mammary epithelial barrier such as ZO-1, occludin, and claudin-3. In vivo, we also found that ZnO NPs can simultaneously induce apoptosis, necroptosis, and pyroptosis, called PANoptosis. Additionally, using EpH4-Ev cells to simulate an in vitro mammary epithelial barrier model, we observed that ZnO NPs effectively disrupted the integrity of mammary epithelial barrier and induced PANoptosis. Furthermore, we confirmed that PANoptosis was responsible for the mammary epithelial barrier disruption induced by ZnO NPs. Moreover, we identified that ZBP1 was the primary mechanism of ZnO NPs inducing PANoptosis. These discoveries are designed to enhance our comprehension of the mechanisms underlying mammary epithelial barrier disruption caused by ZnO NPs, and we aim to highlight the potential hazards associated with daily usage and therapeutic exposure to ZnO NPs during lactation.

PANoptosis: a new insight for oral diseases

PANoptosis, a burgeoning area of research, is a unique type of programmed cell death typified by pyroptosis, apoptosis, and necroptosis, yet it defies singular classification by any one mode of death. The assembly and activation of PANoptosomes are pivotal processes in PANoptosis, with several PANoptosomes already identified. Linkages between PANoptosis and the pathophysiology of various systemic illnesses are established, with increasing recognition of its association with oral ailments. This paper aims to deepen understanding by conducting a comprehensive analysis of the molecular pathways driving PANoptosis and exploring its potential implications in oral diseases.

PANoptosis: Novel insight into regulated cell death and its potential role in cardiovascular diseases (Review)

PANoptosis, a complex form of proinflammatory programmed cell death, including apoptosis, pyroptosis and necroptosis, has been an emerging concept in recent years that has been widely reported in cancer, infectious diseases and neurological disorders. Cardiovascular diseases (CVDs) are an important global health problem, posing a serious threat to individuals' lives. An increasing body of research shows that inflammation has a pivotal role in CVDs, which provides an important theoretical basis for PANoptosis to promote the progression of CVDs. To date, only sporadic studies on PANoptosis in CVDs have been reported and its role in the field of CVDs has not been fully explored. Elucidating the various modes of cardiomyocyte death, the specific molecular mechanisms and the links among the various modes of death under various stressful stimuli is of notable clinical significance for a deeper understanding of the pathophysiology of CVDs. The present review summarizes the molecular mechanisms of apoptosis, pyroptosis, necroptosis and PANoptosis and their prospects in the field of CVDs.

Identification of PANoptosis-relevant subgroups and predicting signature to evaluate the prognosis and immune landscape of patients with biliary tract cancer

BACKGROUND

This study conducted molecular subtyping of biliary tract cancer patients based on 19 PANoptosis-related gene signatures.

METHODS

Through consensus clustering, patients were categorized into two subtypes, A and B. By integrating multi-omics data and clinical information from different cohorts, we elucidated the association between different subtypes of biliary tract cancer and patient prognosis, which correlated with the immune infiltration characteristics of patients.

RESULTS

LASSO regression analysis was performed on the 19 gene signatures, and we constructed and validated a 9-gene risk score prognostic model that accurately predicts the overall survival rate of different biliary tract cancer patients. Additionally, we developed a predictive nomogram demonstrating the clinical utility and robustness of our model. Further analysis of the risk score-based immune landscape highlighted potential associations with immune cell infiltration, chemotherapy, and immune therapy response.

CONCLUSION

Our study provides valuable insights into personalized treatment strategies for biliary tract cancer, which are crucial for improving patient prognosis and guiding treatment decisions in clinical practice.

Concurrent genotyping and expression of NLRP3 inflammasome in pityriasis versicolor patient's skin lesions

The goal of this study is to investigate the impact of the rs35829419 SNP on the serum level of NLRP3, and to assess the relationship between NLRP3 and its SNP and vulnerability to Pityriasis versicolor. Pityriasis versicolor (PV) is one of the most frequent skin conditions linked to skin pigmentation changes. Malassezia plays a key role in the pathogenesis of PV. A case-control study, 50 patients with pityriasis versicolor and 44 healthy controls. Real-time PCR was used to genotype NLRP3 (rs35829419) and ELISA assay of NLRP3 levels in tissue samples. There was a significantly higher median NLPR3 levels in PV patients than controls. A significant predominance of A allele of Q 705 K was in patients than controls. The risk of having the disease in the presence of A allele is nearly 10 times than having C allele. In PV patients, there was a significant relationship between NLPR3 levels and Q 705 K genotypes with higher NLPR3 levels in AA genotype. A potential correlation between PV and the Q705K polymorphism, pointing to evidence of NLRP3 alteration in PV patients. The NLRP3 inflammasome may be an appropriate therapeutic target for Malassezia-associated skin disorders.

Adaptive fungal invasion of bat cells

A fungus uses different cell entry strategies, depending on its host's hibernation status.

Mechanism of Vaginal Epithelial Cell Pyroptosis Induced by the NLRP3 Inflammasome in Vulvovaginal Candidiasis

PROBLEM

Vulvovaginal candidiasis (VVC) is a common mucosal fungal infection, and Candida albicans is the main causative agent. The NLRP3 inflammasome plays an important role in VVC, but the underlying mechanism is unknown.

METHOD OF STUDY

Vaginal epithelial cells were divided into three groups: control, C. albicans strain SC5314 (wild-type, WT), and WT+ Matt Cooper Compound 950 (MCC950, a specific NLRP3 inhibitor). After human vaginal epithelial cells were pretreated with 1 µmol/L MCC950 for 2 h, C. albicans (MOI = 1) was cocultured with the human vaginal epithelial cells for 12 h. The cell supernatants were collected, LDH was detected, and the IL-1β and IL-18 levels were determined by ELISA. The expression of the pyroptosis-related proteins NLRP3, Caspase-1 p20 and GSDMD was measured by Western blotting analysis. The protein expression of the pyroptosis-related N-terminus of GSDMD (GSDMD-N) was detected by immunofluorescence.

RESULTS

In this study, we showed that the WT C. albicans strain induced pyroptosis in vaginal epithelial cells, as indicated by the LDH and proinflammatory cytokine levels and the upregulated levels of the pyroptosis-related proteins NLRP3, Caspase-1 p20, and GSDMD-N. MCC950 reversed the changes in the expression of these proteins and proinflammatory cytokines in vaginal epithelial cells.

CONCLUSION

C. albicans activated the NLRP3 inflammasome to induce vaginal epithelial cell pyroptosis. MCC950 inhibited the NLRP3 inflammasome, reduced vaginal epithelial cell pyroptosis, and decreased the release of inflammatory cytokines.

PANoptosis, an indicator of COVID-19 severity and outcomes

Coronavirus disease 2019 (COVID-19) has been wreaking havoc for 3 years. PANoptosis, a distinct and physiologically relevant inflammatory programmed cell death, perpetuates cytokine storm and multi-organ injuries in COVID-19. Although PANoptosis performs indispensable roles in host defense, further investigation is needed to elucidate the exact processes through which PANoptosis modulates immunological responses and prognosis in COVID-19. This study conducted a bioinformatics analysis of online single-cell RNA sequence (scRNA-seq) and bulk RNA-seq datasets to explore the potential of PANoptosis as an indicator of COVID-19 severity. The degree of PANoptosis in bronchoalveolar lavage fluid (BALF) and peripheral blood mononuclear cells (PBMC) indicated the severity of COVID-19. Single-cell transcriptomics identified pro-inflammatory monocytes as one of the primary sites of PANoptosis in COVID-19. The study subsequently demonstrated the immune and metabolic characteristics of this group of pro-inflammatory monocytes. In addition, the analysis illustrated that dexamethasone was likely to alleviate inflammation in COVID-19 by mitigating PANoptosis. Finally, the study showed that the PANoptosis-related genes could predict the intensive care unit admission (ICU) and outcomes of COVID-19 patients who are hospitalized.

Kongensin a attenuates intervertebral disc degeneration by inhibiting TAK1-mediated PANoptosis of nucleus pulposus cells

Low back pain (LBP) is most commonly caused by intervertebral disc degeneration (IVDD). Pyroptosis, apoptosis, and necroptosis are crucial in IVDD pathogenesis; however, possible simultaneous occurrence in IVDD and co-regulation between the pathways and the regulatory mechanisms have not been investigated. PANoptosis is a regulated cell death (RCD) pathway with the key characteristics of pyroptosis, apoptosis, and necroptosis. This study revealed that tert-butyl hydroperoxide (TBHP) altered the expression of key proteins involved in PANoptosis in nucleus pulposus cells (NPCs). Furthermore, the natural product Kongensin A (KA), which has potential anti-necrotic and anti-inflammatory properties, inhibited PANoptosis. TAK1, often referred to as mitogen-activated protein kinase kinase kinase 7 (Map3k7), is a key regulator of innate immunity, cell death, inflammation, and cellular homeostasis; however, the physiological roles and regulatory mechanisms underlying IVDD remain unclear. In this study, we discovered that KA can upregulate TAK1 expression in NPCs, -which inhibits PANoptosis by suppressing oxidative stress. In conclusion, our results suggest that KA inhibits PANoptosis and delays IVDD progression in NPCs by upregulating TAK1 expression to maintain mitochondrial redox balance. Consequently, targeting TAK1 may be a promising therapeutic approach for IVDD therapy.

Four-Arm δ-Ornithine-Based Polypeptoids Resensitize Voriconazole against Azole-Resistant C. albicans

Worldwide Candida albicans infections cause a huge burden in healthcare and the efficacy of traditional antifungals is diminished because of the rapid development of antifungal resistance. It is necessary to develop new antifungals or new strategies to make multidrug-resistant (MDR) C. albicans to resensitize to existing antifungal drugs. In this work, a series of 4-arm polypeptoids (FAPs) were synthesized through grafting linear ε-l-lysine or δ-ornithine-based oligopeptides to a trimeric lysine core. The most potent 4R-O7 exhibited excellent activities toward three sensitive and two MDR C. albicans strains with MIC values as low as 24-48 μg/mL (vs 375 μg/mL for ε-polylysine, ε-PL). The mechanism studies revealed that 4R-O7 penetrated the cell membrane and generated ROS to kill cells. 4R-O7 exhibited a synergistic effect (FICI < 0.5) with voriconazole (VOR) and also assisted VOR to restore its efficacy to MDR C. albicans. In addition, the combined use of 4R-O7 and VOR significantly improved the elimination efficacy of mature C. albicans biofilms and enhanced the potency in a mouse subcutaneous C. albicans infection model.

Anastrozole Protects against Human Coronavirus Infection by Ameliorating the Reactive Oxygen Species-Mediated Inflammatory Response

The common human coronavirus (HCoV) exhibits mild disease with upper respiratory infection and common cold symptoms. HCoV-OC43, one of the HCoVs, can be used to screen drug candidates against SARS-CoV-2. We determined the antiviral effects of FDA/EMA-approved drug anastrozole (AZ) on two human coronaviruses, HCoV-OC43 and HCoV-229E, using MRC-5 cells in vitro. The AZ exhibited antiviral effects against HCoV-OC43 and HCoV-229E infection. Subsequent studies focused on HCoV-OC43, which is related to the SARS-CoV-2 family. AZ exhibited anti-viral effects and reduced the secretion of inflammatory cytokines, TNF-α, IL-6, and IL-1β. It also inhibited NF-κB translocation to effectively suppress the inflammatory response. AZ reduced intracellular calcium and reactive oxygen species (ROS) levels, including mitochondrial ROS and Ca2+, induced by the virus. AZ inhibited the expression of NLRP3 inflammasome components and cleaved IL-1β, suggesting that it blocks NLRP3 inflammasome activation in HCoV-OC43-infected cells. Moreover, AZ enhanced cell viability and reduced the expression of cleaved gasdermin D (GSDMD), a marker of pyroptosis. Overall, we demonstrated that AZ exhibits antiviral activity against HCoV-OC43 and HCoV-229E. We specifically focused on its efficacy against HCoV-OC43 and showed its potential to reduce inflammation, inhibit NLRP3 inflammasome activation, mitigate mitochondrial dysfunction, and suppress pyroptosis in infected cells.

Fuzheng Huayu recipe alleviates liver fibrosis via inhibiting NLRP3 inflammasome activation in macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Fuzheng Huayu recipe (FZHY) is a commonly used Traditional Chinese Medicine formula for treating liver fibrosis in clinical settings. Despite its widespread use, the specific curative effects and underlying pharmacological mechanisms of FZHY in treating liver fibrosis are not yet fully understood.

AIM AND STUDY

This study aims to investigate the antifibrotic mechanism of FZHY treatment by exploring its effects on the activation of NOD-like receptor protein 3 (NLRP3) inflammasome in macrophages.

MATERIALS AND METHODS

In order to investigate the impact of FZHY on the activation and priming of NLRP3 inflammasome in clinical trials and animal experiments using immunohistochemistry and Western blotting. Twenty-four C57BL/6 mice were used to induce liver fibrosis by feeding a diet that contained 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). To study inflammasome function, Lipopolysaccharide (LPS)/adenine triphosphate (ATP) induced NLRP3 inflammasome activation was induced in bone marrow-derived macrophages (BMDMs) isolated from wild mice. The effects of macrophage NLRP3 inflammasome activation on the function of hepatic stellate cells (HSCs) were explored by treating primary HSCs with preconditioned media from BMDMs culture.

RESULTS

FZHY treatment resulted in the downregulation of NLRP3 protein expression and inhibition of its priming and activation in both human fibrotic livers and DDC-induced liver fibrosis. Furthermore, FZHY was observed to block the activation of the NLRP3 inflammasome pathway, which can lead to excessive inflammatory cytokine release in supernatants and cell lysates in response to LPS and ATP. Lastly, treatment with FZHY was able to inhibit the activation of HSCs induced by supernatants from macrophages.

CONCLUSIONS

FZHY has been shown to potentially prevent NLRP3 inflammasome activation in macrophages which can result in the suppression of HSCs activation. Ultimately, these effects may lead to the improvement of liver fibrosis. The ability of FZHY to act on this novel mechanism represents an important aspect of its therapeutic potential for liver fibrosis.

PANoptosis: Emerging mechanisms and disease implications

PANoptosis, a unique new form of programmed cell death (PCD), is characterized by pyroptosis, apoptosis, and necroptosis, but it cannot be explained by pyroptosis, apoptosis or necroptosis alone. Assembly of the PANoptosome complex is a key feature of PANoptosis. To date, four kinds of PANoptosomes with distinct sensors and regulators have been defined, namely Z-DNA binding protein 1 (ZBP1) PANoptosome, absent in melanoma 2 (AIM2) PANoptosome, receptor-interacting protein kinase 1 (RIPK1) PANoptosome, and nucleotide-binding leucine-rich repeat-containing receptor 12 (NLRP12). Each PANoptosome contains three components: sensors for pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs), adaptors as connected bridges, and catalytic effectors or executioners. Mechanistically, different PAMPs or DAMPs are recognized by the sensors in a context-dependent manner, which initiates PANoptosome assembly through adaptors, and ultimately engages synchronous activation of pyroptosis, apoptosis, and necroptosis via different catalytic effectors. Resultantly, PANoptosis is emerged as a prospective and promising therapeutic target for various diseases. This review covers the accumulating evidence about the roles and mechanisms of PANoptosis in innate immunity and discusses the attractive prospect of manipulating PANoptosis as a new treatment for diseases.

Th2-dependent disappearance and phenotypic conversion of mouse alveolar macrophages

Alveolar macrophages (alvMs) play an important role for maintenance of lung function by constant removal of cellular debris in the alveolar space. They further contribute to defense against microbial or viral infections and limit tissue damage during acute lung injury. alvMs arise from embryonic progenitor cells, seed the alveoli before birth, and have life-long self-renewing capacity. However, recruited monocytes may also help to restore the alvM population after depletion caused by toxins or influenza virus infection. At present, the population dynamics and cellular plasticity of alvMs during allergic lung inflammation is poorly defined. To address this point, we used a mouse model of Aspergillus fumigatus-induced allergic lung inflammation and observed that Th2-derived IL-4 and IL-13 caused almost complete disappearance of alvMs. This effect required STAT6 expression in alvMs and also occurred in various other settings of type 2 immunity-mediated lung inflammation or administration of IL-4 complexes to the lung. In addition, Th2 cells promoted conversion of alvMs to alternatively activated macrophages and multinucleated giant cells. Given the well-established role of alvMs for maintenance of lung function, this process may have implications for resolution of inflammation and tissue homeostasis in allergic asthma.

The Redox Protein High-Mobility Group Box 1 in Cell Death and Cancer

Significance: As a redox-sensitive protein, high-mobility group box 1 (HMGB1) is implicated in regulating stress responses to oxidative damage and cell death, which are closely related to the pathology of inflammatory diseases, including cancer. Recent Advances: HMGB1 is a nonhistone nuclear protein that acts as a deoxyribonucleic acid chaperone to control chromosomal structure and function. HMGB1 can also be released into the extracellular space and function as a damage-associated molecular pattern protein during cell death, including during apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis, alkaliptosis, and cuproptosis. Once released, HMGB1 binds to membrane receptors to shape immune and metabolic responses. In addition to subcellular localization, the function and activity of HMGB1 also depend on its redox state and protein posttranslational modifications. Abnormal HMGB1 plays a dual role in tumorigenesis and anticancer therapy (e.g., chemotherapy, radiation therapy, and immunotherapy) depending on the tumor types and stages. Critical Issues: A comprehensive understanding of the role of HMGB1 in cellular redox homeostasis is important for deciphering normal cellular functions and pathological manifestations. In this review, we discuss compartmental-defined roles of HMGB1 in regulating cell death and cancer. Understanding these advances may help us develop potential HMGB1-targeting drugs or approaches to treat oxidative stress-related diseases or pathological conditions. Future Directions: Further studies are required to dissect the mechanism by which HMGB1 maintains redox homeostasis under different stress conditions. A multidisciplinary effort is also required to evaluate the potential applications of precisely targeting the HMGB1 pathway in human health and disease. Antioxid. Redox Signal. 39, 569-590.

A role for fibroblast-derived SASP factors in the activation of pyroptotic cell death in mammary epithelial cells

In normal tissue homeostasis, bidirectional communication between different cell types can shape numerous biological outcomes. Many studies have documented instances of reciprocal communication between fibroblasts and cancer cells that functionally change cancer cell behavior. However, less is known about how these heterotypic interactions shape epithelial cell function in the absence of oncogenic transformation. Furthermore, fibroblasts are prone to undergo senescence, which is typified by an irreversible cell cycle arrest. Senescent fibroblasts are also known to secrete various cytokines into the extracellular space; a phenomenon that is termed the senescence-associated secretory phenotype (SASP). While the role of fibroblast-derived SASP factors on cancer cells has been well studied, the impact of these factors on normal epithelial cells remains poorly understood. We discovered that treatment of normal mammary epithelial cells with conditioned media from senescent fibroblasts (SASP CM) results in a caspase-dependent cell death. This capacity of SASP CM to cause cell death is maintained across multiple senescence-inducing stimuli. However, the activation of oncogenic signaling in mammary epithelial cells mitigates the ability of SASP CM to induce cell death. Despite the reliance of this cell death on caspase activation, we discovered that SASP CM does not cause cell death by the extrinsic or intrinsic apoptotic pathway. Instead, these cells die by an NLRP3, caspase-1, and gasdermin D-dependent induction of pyroptosis. Taken together, our findings reveal that senescent fibroblasts can cause pyroptosis in neighboring mammary epithelial cells, which has implications for therapeutic strategies that perturb the behavior of senescent cells.

The gasdermin protein family: emerging roles in gastrointestinal health and disease

Since the identification and characterization of gasdermin (GSDM) D as the main effector of inflammatory regulated cell death (or pyroptosis), literature on the GSDM family of pore-forming proteins is rapidly expanding, revealing novel mechanisms regulating their expression and functions that go beyond pyroptosis. Indeed, a growing body of evidence corroborates the importance of GSDMs within the gastrointestinal system, underscoring their critical contributions to the pathophysiology of gastrointestinal cancers, enteric infections and gut mucosal inflammation, such as inflammatory bowel disease. However, with this increase in knowledge, several important and controversial issues have arisen regarding basic GSDM biology and its role(s) during health and disease states. These include critical questions centred around GSDM-dependent lytic versus non-lytic functions, the biological activities of cleaved versus full-length proteins, the differential roles of GSDM-expressing mucosal immune versus epithelial cells, and whether GSDMs promote pathogenic or protective effects during specific disease settings. This Review provides a comprehensive summary and interpretation of the current literature on GSDM biology, specifically focusing on the gastrointestinal tract, highlighting the main controversial issues and their clinical implications, and addressing future areas of research to unravel the specific role(s) of this intriguing, yet enigmatic, family of proteins.

Identification of PANoptosis-relevant subgroups to evaluate the prognosis and immune landscape of patients with liver hepatocellular carcinoma

Liver hepatocellular carcinoma (LIHC) is one of the most common malignant tumors, which is difficult to be diagnosed at an early stage due to its poor prognosis. Despite the fact that PANoptosis is important in the occurrence and development of tumors, no bioinformatic explanation related to PANoptosis in LIHC can be found. A bioinformatics analysis on the data of LIHC patients in TCGA database was carried out on the basis of previously identified PANoptosis-related genes (PRGs). LIHC patients were divided into two PRG clusters whose gene characteristics of differentially expressed genes (DEGs) were discussed. According to DEGs, the patients were further divided into two DEG clusters, and prognostic-related DEGs (PRDEGs) were applied to risk score calculation, the latter of which turned out to be practical in identifying the relationship among risk score, patient prognosis, and immune landscape. The results suggested that PRGs and relevant clusters were bound up with the survival and immunity of patients. Moreover, the prognostic value based on two PRDEGs was evaluated, the risk scoring model was constructed, and the nomogram model for predicting the survival rate of patients was further developed. Therefore, it was found that the prognosis of the high-risk subgroup was poor. Additionally, three factors, namely, the abundance of immune cells, the expression of immune checkpoints, and immunotherapy and chemotherapy were considered to be associated with the risk score. RT-qPCR results indicated higher positive expression of CD8A and CXCL6 in both LIHC tissues and most human liver cancer cell lines. In summary, the results suggested that PANoptosis was bound up with LIHC-related survival and immunity. Two PRDEGs were identified as potential markers. Thus, the understanding of PANoptosis in LIHC was enriched, with some strategies provided for the clinical therapy of LIHC.

A 360° view of the inflammasome: Mechanisms of activation, cell death, and diseases

Inflammasomes are critical sentinels of the innate immune system that respond to threats to the host through recognition of distinct molecules, known as pathogen- or damage-associated molecular patterns (PAMPs/DAMPs), or disruptions of cellular homeostasis, referred to as homeostasis-altering molecular processes (HAMPs) or effector-triggered immunity (ETI). Several distinct proteins nucleate inflammasomes, including NLRP1, CARD8, NLRP3, NLRP6, NLRC4/NAIP, AIM2, pyrin, and caspases-4/-5/-11. This diverse array of sensors strengthens the inflammasome response through redundancy and plasticity. Here, we present an overview of these pathways, outlining the mechanisms of inflammasome formation, subcellular regulation, and pyroptosis, and discuss the wide-reaching effects of inflammasomes in human disease.

Mitochondrial dysfunctions induce PANoptosis and ferroptosis in cerebral ischemia/reperfusion injury: from pathology to therapeutic potential

Ischemic stroke (IS) accounts for more than 80% of the total stroke, which represents the leading cause of mortality and disability worldwide. Cerebral ischemia/reperfusion injury (CI/RI) is a cascade of pathophysiological events following the restoration of blood flow and reoxygenation, which not only directly damages brain tissue, but also enhances a series of pathological signaling cascades, contributing to inflammation, further aggravate the damage of brain tissue. Paradoxically, there are still no effective methods to prevent CI/RI, since the detailed underlying mechanisms remain vague. Mitochondrial dysfunctions, which are characterized by mitochondrial oxidative stress, Ca²⁺ overload, iron dyshomeostasis, mitochondrial DNA (mtDNA) defects and mitochondrial quality control (MQC) disruption, are closely relevant to the pathological process of CI/RI. There is increasing evidence that mitochondrial dysfunctions play vital roles in the regulation of programmed cell deaths (PCDs) such as ferroptosis and PANoptosis, a newly proposed conception of cell deaths characterized by a unique form of innate immune inflammatory cell death that regulated by multifaceted PANoptosome complexes. In the present review, we highlight the mechanisms underlying mitochondrial dysfunctions and how this key event contributes to inflammatory response as well as cell death modes during CI/RI. Neuroprotective agents targeting mitochondrial dysfunctions may serve as a promising treatment strategy to alleviate serious secondary brain injuries. A comprehensive insight into mitochondrial dysfunctions-mediated PCDs can help provide more effective strategies to guide therapies of CI/RI in IS.

Time-Course Transcriptomic Analysis Reveals the Crucial Roles of PANoptosis in Fungal Keratitis

Purpose

Fungal keratitis (FK) is a serious corneal infection with high morbidity. Host immune responses function as a double-edged sword by eradicating fungal pathogens while also causing corneal damage, dictating the severity, progression, and outcome of FK. However, the underlying immunopathogenesis remains elusive.

Methods

Time-course transcriptome was performed to illustrate the dynamic immune landscape in a mouse model of FK. Integrated bioinformatic analyses included identification of differentially expressed genes, time series clustering, Gene Ontology enrichment, and inference of infiltrating immune cells. Gene expression was verified by quantitative polymerase chain reaction (qPCR), Western blot, or immunohistochemistry.

Results

FK mice exhibited dynamic immune responses with concerted trends with clinical score, transcriptional alteration, and immune cell infiltration score peaking at 3 days post infection (dpi). Disrupted substrate metabolism, broad immune activation, and corneal wound healing occurred sequentially in early, middle, and late stages of FK. Meanwhile, dynamics of infiltrating innate and adaptive immune cells displayed distinct characteristics. Proportions of dendritic cells showed overall decreasing trend with fungal infection, whereas that of macrophages, monocytes, and neutrophils rose sharply in early stage and then gradually decreased as inflammation resolved. Activation of adaptive immune cells was also observed in late stage of infection. Furthermore, shared immune responses and activation of AIM2-, pyrin-, and ZBP1-mediated PANoptosis were revealed across different time points.

Conclusions

Our study profiles the dynamic immune landscape and highlights the crucial roles of PANoptosis in FK pathogenesis. These findings provide novel insights into host responses to fungi and contribute to the development of PANoptosis-targeted therapeutics for patients with FK.

A role for fibroblast-derived SASP factors in the activation of pyroptotic cell death in mammary epithelial cells

In normal tissue homeostasis, bidirectional communication between different cell types can shape numerous biological outcomes. Many studies have documented instances of reciprocal communication between fibroblasts and cancer cells that functionally change cancer cell behavior. However, less is known about how these heterotypic interactions shape epithelial cell function in the absence of oncogenic transformation. Furthermore, fibroblasts are prone to undergo senescence, which is typified by an irreversible cell cycle arrest. Senescent fibroblasts are also known to secrete various cytokines into the extracellular space; a phenomenon that is termed the senescence-associated secretory phenotype (SASP). While the role of fibroblast derived SASP factors on cancer cells has been well studied, the impact of these factors on normal epithelial cells remains poorly understood. We discovered that treatment of normal mammary epithelial cells with conditioned media (CM) from senescent fibroblasts (SASP CM) results in a caspase-dependent cell death. This capacity of SASP CM to cause cell death is maintained across multiple senescence-inducing stimuli. However, the activation of oncogenic signaling in mammary epithelial cells mitigates the ability of SASP CM to induce cell death. Despite the reliance of this cell death on caspase activation, we discovered that SASP CM does not cause cell death by the extrinsic or intrinsic apoptotic pathway. Instead, these cells die by an NLRP3, caspase-1, and gasdermin D (GSDMD)-dependent induction of pyroptosis. Taken together, our findings reveal that senescent fibroblasts can cause pyroptosis in neighboring mammary epithelial cells, which has implications for therapeutic strategies that perturb the behavior of senescent cells.

Significance of Pulmonary Endothelial Injury and the Role of Cyclooxygenase-2 and Prostanoid Signaling

The endothelium plays a key role in the dynamic balance of hemodynamic, humoral and inflammatory processes in the human body. Its central importance and the resulting therapeutic concepts are the subject of ongoing research efforts and form the basis for the treatment of numerous diseases. The pulmonary endothelium is an essential component for the gas exchange in humans. Pulmonary endothelial dysfunction has serious consequences for the oxygenation and the gas exchange in humans with the potential of consecutive multiple organ failure. Therefore, in this review, the dysfunction of the pulmonary endothel due to viral, bacterial, and fungal infections, ventilator-related injury, and aspiration is presented in a medical context. Selected aspects of the interaction of endothelial cells with primarily alveolar macrophages are reviewed in more detail. Elucidation of underlying causes and mechanisms of damage and repair may lead to new therapeutic approaches. Specific emphasis is placed on the processes leading to the induction of cyclooxygenase-2 and downstream prostanoid-based signaling pathways associated with this enzyme.

PANoptosis: A Cell Death Characterized by Pyroptosis, Apoptosis, and Necroptosis

PANoptosis is a new cell death proposed by Malireddi et al in 2019, which is characterized by pyroptosis, apoptosis and necroptosis, but cannot be explained by any of them alone. The interaction between pyroptosis, apoptosis and necroptosis is involved in PANoptosis. In this review, from the perspective of PANoptosis, we focus on the relationship between pyroptosis, apoptosis and necroptosis, the key molecules in the process of PANoptosis and the formation of PANoptosome, as well as the role of PANoptosis in diseases. We aim to understand the mechanism of PANoptosis and provide a basis for targeted intervention of PANoptosis-related molecules to treat human diseases.

Paradoxical roles for programmed cell death signaling during viral infection of the central nervous system

Programmed cell death (PCD) is an essential mechanism of antimicrobial defense. Recent work has revealed an unexpected diversity in the types of PCD elicited during infection, as well as defined unique roles for different PCD modalities in shaping the immune response. Here, we review recent work describing unique ways in which PCD signaling operates within the infected central nervous system (CNS). These studies reveal striking complexity in the regulation of PCD signaling by CNS cells, including both protective and pathological outcomes in the control of infection. Studies defining the specialized molecular mechanisms shaping PCD responses in the CNS promise to yield much needed new insights into the pathogenesis of neuroinvasive viral infection, informing future therapeutic development.

Different modalities of host cell death and their impact on Mycobacterium tuberculosis infection

Mycobacterium tuberculosis (Mtb) is the pathogen that causes tuberculosis (TB), a leading infectious disease of humans worldwide. One of the main histopathological hallmarks of TB is the formation of granulomas comprised of elaborately organized aggregates of immune cells containing the pathogen. Dissemination of Mtb from infected cells in the granulomas due to host and mycobacterial factors induces multiple cell death modalities in infected cells. Based on molecular mechanism, morphological characteristics, and signal dependency, there are two main categories of cell death: programmed and nonprogrammed. Programmed cell death (PCD), such as apoptosis and autophagy, is associated with a protective response to Mtb by keeping the bacteria encased within dead macrophages that can be readily phagocytosed by arriving in uninfected or neighboring cells. In contrast, non-PCD necrotic cell death favors the pathogen, resulting in bacterial release into the extracellular environment. Multiple types of cell death in the PCD category, including pyroptosis, necroptosis, ferroptosis, ETosis, parthanatos, and PANoptosis, may be involved in Mtb infection. Since PCD pathways are essential for host immunity to Mtb, therapeutic compounds targeting cell death signaling pathways have been experimentally tested for TB treatment. This review summarizes different modalities of Mtb-mediated host cell deaths, the molecular mechanisms underpinning host cell death during Mtb infection, and its potential implications for host immunity. In addition, targeting host cell death pathways as potential therapeutic and preventive approaches against Mtb infection is also discussed.

Inflammasome and Inflammatory Programmed Cell Death in Chromoblastomycosis

Chromoblastomycosis (CBM) is a chronic, progressive fungal disease of the skin and subcutaneous tissue caused by a group of dematiaceous fungi. Verrucous lesions present parasite-rich granulomas and predominance of a Th2 patterns of cytokines. The inflammasome constitutes a macromolecular protein complex that play a role in the activation of caspase 1 that cleaves pro-IL1β and pro-IL18, essential mediators of inflammation, and also activates pyroptosis. We intended to explore the presence and a possible role of inflammasome elements in cutaneous human lesions in CBM, considering the expression of IL1β, IL18, caspase 1, NLRP1, and also RIPK3, a key downstream component of necroptosis signaling. 35 skin biopsies of cutaneous lesions of verrucous form of CBM and 10 biopsies from normal skin were selected. The diagnosis was based on histological and clinical analysis. An immunohistochemical protocol was performed. The histopathological analysis evidenced epidermis with hyperkeratosis, irregular acanthosis, and micro abscesses. The dermis presented suppurative granulomas and inflammatory infiltrate composed by giant cells, macrophages, epithelioid cells, lymphocytes, and some eosinophils. Positive cells were distributed in the inflammatory infiltrate, with an increased number of cells expressing caspase 1, IL1β and IL18. Cells expressing RIPK3 and NLRP1 were less frequent. The intense presence of caspase 1, IL1β and IL18, allied to NLRP1 expression, suggest that inflammasome and pyroptosis could play a role in the immune response against fungal agents of CBM. Our results, allied to data from literature, could suggest that inflammasome-mediated response and pyroptosis could be a target to be explored to decrease CBM lesions.

Molecular mechanisms and roles of pyroptosis in acute lung injury

ABSTRACT

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), which are characterized by excessive inflammation and accompanied by diffuse injury of alveoli, can result in severe respiratory failures. The morbidity and mortality of patients remain high because the major treatments for ALI/ARDS are mainly supportive due to the lack of effective therapies. Numerous studies have demonstrated that the aggravation of coronavirus disease 2019 (COVID-19) leads to severe pneumonia and even ARDS. Pyroptosis, a biological process identified as a type of programed cell death, is mainly triggered by inflammatory caspase activation and is directly meditated by the gasdermin protein family, as well as being associated with the secretion and release of pro-inflammatory cytokines. Clinical and experimental evidence corroborates that pyroptosis of various cells in the lung, such as immune cells and structural cells, may play an important role in the pathogenesis of "cytokine storms" in ALI/ARDS, including those induced by COVID-19. Here, with a focus on ALI/ARDS and COVID-19, we summarized the recent advances in this field and proposed the theory of an inflammatory cascade in pyroptosis to identify new targets and pave the way for new approaches to treat these diseases.

PANoptosis-based molecular clustering and prognostic signature predicts patient survival and immune landscape in colon cancer

PANoptosis is a newly-discovered cell death pathway that involves crosstalk and co-ordination between pyroptosis, apoptosis, and necroptosis processes. However, the roles of PANoptosis-related genes (PRGs) in prognosis and immune landscape of colon cancer remain widely unknown. Here, we performed a bioinformatics analysis of expression data of nineteen PRGs identified from previous studies and clinical data of colon cancer patients obtained from TCGA and GEO databases. Colon cancer cases were divided into two PRG clusters, and prognosis-related differentially expressed genes (PRDEGs) were identified. The patient data were then separated into two corresponding distinct gene clusters, and the relationship between the risk score, patient prognosis, and immune landscape was analyzed. The identified PRGs and gene clusters correlated with patient survival and immune system and cancer-related biological processes and pathways. A prognosis signature based on seven genes was identified, and patients were divided into high-risk and low-risk groups based on the calculated risk score. A nomogram model for prediction of patient survival was also developed based on the risk score and other clinical features. Accordingly, the high-risk group showed worse prognosis, and the risk score was related to immune cell abundance, cancer stem cell (CSC) index, checkpoint expression, and response to immunotherapy and chemotherapeutic drugs. Results of quantitative real-time polymerase chain reaction (qRT-PCR) showed that LGR5 and VSIG4 were differentially expressed between normal and colon cancer samples. In conclusion, we demonstrated the potential of PANoptosis-based molecular clustering and prognostic signatures for prediction of patient survival and tumor microenvironment (TME) in colon cancer. Our findings may improve our understanding of the role of PANoptosis in colon cancer, and enable the development of more effective treatment strategies.

Host's Immunity and Candida Species Associated with Denture Stomatitis: A Narrative Review

Denture-related Candida stomatitis, which has been described clinically in the literature, is either localized or generalized inflammation of the oral mucosa in connection with a removable prosthesis. During this inflammatory process, the mycobacterial biofilm and the host’s immune response play an essential role. Among microorganisms of this mixed biofilm, the Candida species proliferates easily and changes from a commensal to an opportunistic pathogen. In this situation, the relationship between the Candida spp. and the host is influenced by the presence of the denture and conditioned both by the immune response and the oral microbiota. Specifically, this fungus is able to hijack the innate immune system of its host to cause infection. Additionally, older edentulous wearers of dentures may experience an imbalanced and decreased oral microbiome diversity. Under these conditions, the immune deficiency of these aging patients often promotes the spread of commensals and pathogens. The present narrative review aimed to analyze the innate and adaptive immune responses of patients with denture stomatitis and more particularly the involvement of Candida albicans sp. associated with this pathology.

Biological Effects and Mechanisms of Caspases in Early Brain Injury after Subarachnoid Hemorrhage

Caspases are an evolutionarily conserved family of proteases responsible for mediating and initiating cell death signals. In the past, the dysregulated activation of caspases was reported to play diverse but equally essential roles in neurodegenerative diseases, such as brain injury and neuroinflammatory diseases. A subarachnoid hemorrhage (SAH) is a traumatic event that is either immediately lethal or induces a high risk of stroke and neurological deficits. Currently, the prognosis of SAH after treatment is not ideal. Early brain injury (EBI) is considered one of the main factors contributing to the poor prognosis of SAH. The mechanisms of EBI are complex and associated with oxidative stress, neuroinflammation, blood-brain barrier disruption, and cell death. Based on mounting evidence, caspases are involved in neuronal apoptosis or death, endothelial cell apoptosis, and increased inflammatory cytokine-induced by apoptosis, pyroptosis, and necroptosis in the initial stages after SAH. Caspases can simultaneously mediate multiple death modes and regulate each other. Caspase inhibitors (including XIAP, VX-765, and Z-VAD-FMK) play an essential role in ameliorating EBI after SAH. In this review, we explore the related pathways mediated by caspases and their reciprocal regulation patterns after SAH. Furthermore, we focus on the extensive crosstalk of caspases as a potential area of research on therapeutic strategies for treating EBI after SAH.

Role of Pyroptosis in Gynecological Oncology and Its Therapeutic Regulation

With the continuous advances in molecular biotechnology, many new cell death methods have been discovered. Pyroptosis is a programmed cell death process that differs from apoptosis and autophagy in cell morphology and function. Compared with apoptosis and autophagy, pyroptosis is primarily mediated by intracellular inflammasome and gasdermin D of the gasdermin protein family and involves the release of numerous inflammatory factors. Pyroptosis has been found to be involved in the occurrence and development of infectious diseases and other diseases involving the nervous system and the cardiovascular system. Recent studies have also reported the occurrence of pyroptosis in tumor cells. Accordingly, exploring its effect on tumors has become one of the research hotspots. Herein, recent research progress on pyroptosis is reviewed, especially its role in the development of gynecological tumors. As the pathogenesis of gynecological tumor is better understood, new targets have been introduced for the prevention and clinical treatment of gynecological tumors.

Activation and Regulation of NLRP3 by Sterile and Infectious Insults

Nod-Like Receptor (NLR) is the largest family of Pathogen Recognition Receptors (PRRs) that patrols the cytosolic environment. NLR engagement drives caspase-1 activation that cleaves pro-IL-1B which then gets secreted. Released IL-1B recruits immune cells to the site of infection/injury. Caspase-1 also cleaves Gasdermin-D (GSDM-D) that forms pores within the plasma membrane driving inflammatory cell death called pyroptosis. NLRP3 is the most extensively studied NLR. The NLRP3 gene is encoded by 9 exons, where exon 1 codes for pyrin domain, exon 3 codes for NACHT domain, and Leucine Rich Repeat (LRR) domain is coded by exon 4-9. Exon 2 codes for a highly disorganized loop that connects the rest of the protein to the pyrin domain and may be involved in NLRP3 regulation. The NLRP3 inflammasome is activated by many structurally divergent agonists of microbial, environmental, and host origin. Activated NLRP3 interacts with an adaptor protein, ASC, that bridges it to pro-Caspase-1 forming a multi-protein complex called inflammasome. Dysregulation of NLRP3 inflammasome activity is a hallmark of pathogenesis in several human diseases, indicating its highly significant clinical relevance. In this review, we summarize the existing knowledge about the mechanism of activation of NLRP3 and its regulation during activation by infectious and sterile triggers.

PANoptosis in Viral Infection: The Missing Puzzle Piece in the Cell Death Field

In the past decade, emerging viral outbreaks like SARS-CoV-2, Zika and Ebola have presented major challenges to the global health system. Viruses are unique pathogens in that they fully rely on the host cell to complete their lifecycle and potentiate disease. Therefore, programmed cell death (PCD), a key component of the host innate immune response, is an effective strategy for the host cell to curb viral spread. The most well-established PCD pathways, pyroptosis, apoptosis and necroptosis, can be activated in response to viruses. Recently, extensive crosstalk between PCD pathways has been identified, and there is evidence that molecules from all three PCD pathways can be activated during virus infection. These findings have led to the emergence of the concept of PANoptosis, defined as an inflammatory PCD pathway regulated by the PANoptosome complex with key features of pyroptosis, apoptosis, and/or necroptosis that cannot be accounted for by any of these three PCD pathways alone. While PCD is important to eliminate infected cells, many viruses are equipped to hijack host PCD pathways to benefit their own propagation and subvert host defense, and PCD can also lead to the production of inflammatory cytokines and inflammation. Therefore, PANoptosis induced by viral infection contributes to either host defense or viral pathogenesis in context-specific ways. In this review, we will discuss the multi-faceted roles of PCD pathways in controlling viral infections.

Interaction of Mycobacteria With Host Cell Inflammasomes

The inflammasome complex is important for host defense against intracellular bacterial infections. Mycobacterium tuberculosis (Mtb) is a facultative intracellular bacterium which is able to survive in infected macrophages. Here we discuss how the host cell inflammasomes sense Mtb and other related mycobacterial species. Furthermore, we describe the molecular mechanisms of NLRP3 inflammasome sensing of Mtb which involve the type VII secretion system ESX-1, cell surface lipids (TDM/TDB), secreted effector proteins (LpqH, PPE13, EST12, EsxA) and double-stranded RNA acting on the priming and/or activation steps of inflammasome activation. In contrast, Mtb also mediates inhibition of the NLRP3 inflammasome by limiting exposure of cell surface ligands via its hydrolase, Hip1, by inhibiting the host cell cathepsin G protease via the secreted Mtb effector Rv3364c and finally, by limiting intracellular triggers (K+ and Cl- efflux and cytosolic reactive oxygen species production) via its serine/threonine kinase PknF. In addition, Mtb inhibits the AIM2 inflammasome activation via an unknown mechanism. Overall, there is good evidence for a tug-of-war between Mtb trying to limit inflammasome activation and the host cell trying to sense Mtb and activate the inflammasome. The detailed molecular mechanisms and the importance of inflammasome activation for virulence of Mtb or host susceptibility have not been fully investigated.

The mechanism of HMGB1 secretion and release

High mobility group box 1 (HMGB1) is a nonhistone nuclear protein that has multiple functions according to its subcellular location. In the nucleus, HMGB1 is a DNA chaperone that maintains the structure and function of chromosomes. In the cytoplasm, HMGB1 can promote autophagy by binding to BECN1 protein. After its active secretion or passive release, extracellular HMGB1 usually acts as a damage-associated molecular pattern (DAMP) molecule, regulating inflammation and immune responses through different receptors or direct uptake. The secretion and release of HMGB1 is fine-tuned by a variety of factors, including its posttranslational modification (e.g., acetylation, ADP-ribosylation, phosphorylation, and methylation) and the molecular machinery of cell death (e.g., apoptosis, pyroptosis, necroptosis, alkaliptosis, and ferroptosis). In this minireview, we introduce the basic structure and function of HMGB1 and focus on the regulatory mechanism of HMGB1 secretion and release. Understanding these topics may help us develop new HMGB1-targeted drugs for various conditions, especially inflammatory diseases and tissue damage.

A nuclear protein that gets released after cell death or is actively secreted by immune cells offers a promising therapeutic target for treating diseases linked to excessive inflammation. Daolin Tang from the University of Texas Southwestern Medical Center in Dallas, USA, and colleagues review how cellular stresses can trigger the accumulation of HMGB1, a type of alarm signal protein that promotes the recruitment and activation of inflammation-promoting immune cells. The researchers discuss various mechanisms that drive both passive and active release of HMGB1 into the space around cells. These processes, which include enzymatic modifications of the HMGB1 protein, cell–cell interactions and molecular pathways of cell death, could be targeted by drugs to lessen tissue damage and inflammatory disease caused by HMGB1-induced immune responses

Do pyroptosis, apoptosis, and necroptosis (PANoptosis) exist in cerebral ischemia? Evidence from cell and rodent studies

Some scholars have recently developed the concept of PANoptosis in the study of infectious diseases where pyroptosis, apoptosis and necroptosis act in consort in a multimeric protein complex, PANoptosome. This allows all the components of PANoptosis to be regulated simultaneously. PANoptosis provides a new way to study the regulation of cell death, in that different types of cell death may be regulated at the same time. To test whether PANoptosis exists in diseases other than infectious diseases, we chose cerebral ischemia/reperfusion injury as the research model, collected articles researching cerebral ischemia/reperfusion from three major databases, obtained the original research data from these articles by bibliometrics, data mining and other methods, then integrated and analyzed these data. We selected papers that investigated at least two of the components of PANoptosis to check its occurrence in ischemia/reperfusion. In the cell model simulating ischemic brain injury, pyroptosis, apoptosis and necroptosis occur together and this phenomenon exists widely in different passage cell lines or primary neurons. Pyroptosis, apoptosis and necroptosis also occurred in rat and mouse models of ischemia/reperfusion injury. This confirms that PANoptosis is observed in ischemic brain injury and indicates that PANoptosis can be a target in the regulation of various central nervous system diseases.

Nod-like Receptors: Critical Intracellular Sensors for Host Protection and Cell Death in Microbial and Parasitic Infections

Cell death is an essential immunological apparatus of host defense, but dysregulation of mutually inclusive cell deaths poses severe threats during microbial and parasitic infections leading to deleterious consequences in the pathological progression of infectious diseases. Nucleotide-binding oligomerization domain (NOD)-Leucine-rich repeats (LRR)-containing receptors (NLRs), also called nucleotide-binding oligomerization (NOD)-like receptors (NLRs), are major cytosolic pattern recognition receptors (PRRs), their involvement in the orchestration of innate immunity and host defense against bacteria, viruses, fungi and parasites, often results in the cleavage of gasdermin and the release of IL-1β and IL-18, should be tightly regulated. NLRs are functionally diverse and tissue-specific PRRs expressed by both immune and non-immune cells. Beyond the inflammasome activation, NLRs are also involved in NF-κB and MAPK activation signaling, the regulation of type I IFN (IFN-I) production and the inflammatory cell death during microbial infections. Recent advancements of NLRs biology revealed its possible interplay with pyroptotic cell death and inflammatory mediators, such as caspase 1, caspase 11, IFN-I and GSDMD. This review provides the most updated information that caspase 8 skews the NLRP3 inflammasome activation in PANoptosis during pathogen infection. We also update multidimensional roles of NLRP12 in regulating innate immunity in a content-dependent manner: novel interference of NLRP12 on TLRs and NOD derived-signaling cascade, and the recently unveiled regulatory property of NLRP12 in production of type I IFN. Future prospects of exploring NLRs in controlling cell death during parasitic and microbial infection were highlighted.

Genetic Susceptibility to Fungal Infections and Links to Human Ancestry

Over the ages, fungi have associated with different parts of the human body and established symbiotic associations with their host. They are mostly commensal unless there are certain not so well-defined factors that trigger the conversion to a pathogenic state. Some of the factors that induce such transition can be dependent on the fungal species, environment, immunological status of the individual, and most importantly host genetics. In this review, we discuss the different aspects of how host genetics play a role in fungal infection since mutations in several genes make hosts susceptible to such infections. We evaluate how mutations modulate the key recognition between the pathogen associated molecular patterns (PAMP) and the host pattern recognition receptor (PRR) molecules. We discuss the polymorphisms in the genes of the immune system, the way it contributes toward some common fungal infections, and highlight how the immunological status of the host determines fungal recognition and cross-reactivity of some fungal antigens against human proteins that mimic them. We highlight the importance of single nucleotide polymorphisms (SNPs) that are associated with several of the receptor coding genes and discuss how it affects the signaling cascade post-infection, immune evasion, and autoimmune disorders. As part of personalized medicine, we need the application of next-generation techniques as a feasible option to incorporate an individual’s susceptibility toward invasive fungal infections based on predisposing factors. Finally, we discuss the importance of studying genomic ancestry and reveal how genetic differences between the human race are linked to variation in fungal disease susceptibility.