Apoptosis-associated speck-like protein containing a CARD regulates the growth of pancreatic ductal adenocarcinoma

A highly fluorescent and readily accessible all-organic photosensitizer model for advancing image-guided cancer PDT

The potential of using image-guided photodynamic therapy (ig-PDT) for cancer, especially with highly biocompatible fluorescent agents free of heavy atoms, is well recognized. This is due to key advantages related to minimizing adverse side effects associated with standard cancer chemotherapy. However, this theragnostic approach is strongly limited by the lack of synthetically-accessible and easily-modulable chemical scaffolds, enabling the rapid design and construction of advanced agents for clinical ig-PDT. In fact, there are still very few ig-PDT agents clinically approved. Herein we report a readily accessible, easy-tunable and highly fluorescent all-organic small photosensitizer, as a model design for accelerating the development and translation of advanced ig-PDT agents for cancer. This scaffold is based on BODIPY, which assures high fluorescence, accessibility, and ease of performance adaptation by workable chemistry. The optimal PDT performance of this BODIPY dye, tested in highly resistant pancreatic cancer cells, despite its high fluorescent behavior, maintained even after fixation and cancer cell death, is based on its selective accumulation in mitochondria. This induces apoptosis upon illumination, as evidenced by proteomic studies and flow cytometry. All these characteristics make the reported BODIPY-based fluorescent photosensitizer a valuable model for the rapid development of ig-PDT agents for clinical use.

PYCARD gene polymorphisms and susceptibility to periodontal and coronary heart diseases

Numerous studies have established a link between gene variants within the inflammasome complex and the incidence of periodontitis and cardiovascular illness across various ethnic groups. This study investigated the association between PYCARD gene polymorphism and susceptibility to periodontal disease and coronary heart disease (CHD) and their correlation with clinical periodontal indices. A total of 120 participants were enrolled, categorized into four groups: 30 healthy controls (C), 30 patients with generalized periodontitis (P), 30 patients with atherosclerotic CHD but clinically healthy periodontium (AS-C), and 30 patients with both atherosclerotic CHD and generalized periodontitis (AS-P). We recorded demographic data, collected blood samples, and measured periodontal indices, including plaque index, clinical attachment loss, bleeding on probing, and pocket depth. The genomic variant of the PYCARD gene was analyzed using a conventional polymerase reaction. A significant prevalence of T and G allele mutations and a higher distribution of CT and TT genotypes in PYCARD C/T (rs8056505) and the AG genotype in PYCARD A/G (rs372507365) were observed in groups P, AS-P, and AS-C. These single nucleotide polymorphisms (SNPs) were also positively correlated with the severity of clinical periodontitis indices. Our findings suggest that the increased frequency of T and G alleles and the distribution of CT, TT, and AG genotypes in PYCARD SNPs are significantly associated with an elevated risk for periodontal disease and CHD. These SNPs may participate in the pathogenesis of these conditions. The study reinforces the potential role of these genetic markers as risk factors for both diseases in the Iraqi population.

Reframing the link between metabolism and NLRP3 inflammasome: therapeutic opportunities

Inflammasomes are multiprotein signaling platforms in the cytosol that senses exogenous and endogenous danger signals and respond with the maturation and secretion of IL-1β and IL-18 and pyroptosis to induce inflammation and protect the host. The inflammasome best studied is the Nucleotide-binding oligomerization domain, leucine-rich repeat-containing family pyrin domain containing 3 (NLRP3) inflammasome. It is activated in a two-step process: the priming and the activation, leading to sensor NLRP3 oligomerization and recruitment of both adaptor ASC and executioner pro-caspase 1, which is activated by cleavage. Moreover, NLRP3 inflammasome activation is regulated by posttranslational modifications, including ubiquitination/deubiquitination, phosphorylation/dephosphorylation, acetylation/deacetylation, SUMOylation and nitrosylation, and interaction with NLPR3 protein binding partners. Moreover, the connection between it and metabolism is receiving increasing attention in this field. In this review, we present the structure, functions, activation, and regulation of NLRP3, with special emphasis on regulation by mitochondrial dysfunction-mtROS production and metabolic signals, i.e., metabolites as well as enzymes. By understanding the regulation of NLRP3 inflammasome activation, specific inhibitors can be rationally designed for the treatment and prevention of various immune- or metabolic-based diseases. Lastly, we review current NLRP3 inflammasome inhibitors and their mechanism of action.

Identification of a pyroptosis-based model for predicting clinical outcomes from immunotherapy in patients with metastatic melanoma

Immunotherapy has greatly improved outcomes for patients with advanced melanoma, but good predictive biomarkers remain lacking in clinical practice. Although increasing evidence has revealed a vital role of pyroptosis in the tumor microenvironment (TME), it remains unclear for pyroptosis as a predictive biomarker for immunotherapy in melanoma. RNA sequencing data and annotated clinical information of melanoma patients were obtained from four published immunotherapy datasets. LASSO regression analysis was conducted to develop a pyroptosis-based model for quantifying a pyroptosis score in each tumor. Based on four clinical cohorts, we evaluated the predictive capability of the model using multiple immunotherapeutic outcomes, including clinical benefits, overall survival (OS), and progression-free survival (PFS). Furthermore, we depicted the distinctive TME features associated with pyroptosis. Compared with the group with low pyroptosis scores, the group with high pyroptosis scores consistently achieved better durable clinical benefits in four independent cohorts and the meta-cohort. ROC analysis validated that the pyroptosis-based model was a reliable biomarker for predicting clinical benefits from immunotherapy in melanoma. Survival analyses showed that the group with high pyroptosis scores harbored more favorable OS and PFS than those with low pyroptosis scores. Molecular analysis revealed that tumors with high pyroptosis scores displayed a typical immune-inflamed phenotype in TME, including enrichment of immunostimulatory pathways, increased level of tumor-infiltrating lymphocytes, upregulation of immune effectors, and activation of the antitumor immune response. Our findings suggested that the pyroptosis-related model associated with multiple immune-inflamed characteristics might be a reliable tool for predicting clinical benefit and survival outcomes from immunotherapy in melanoma.

Uncoupled pyroptosis and IL-1β secretion downstream of inflammasome signaling

Inflammasomes are supramolecular platforms that organize in response to various damage-associated molecular patterns and pathogen-associated molecular patterns. Upon activation, inflammasome sensors (with or without the help of ASC) activate caspase-1 and other inflammatory caspases that cleave gasdermin D and pro-IL-1β/pro-IL-18, leading to pyroptosis and mature cytokine secretion. Pyroptosis enables intracellular pathogen niche disruption and intracellular content release at the cost of cell death, inducing pro-inflammatory responses in the neighboring cells. IL-1β is a potent pro-inflammatory regulator for neutrophil recruitment, macrophage activation, and T-cell expansion. Thus, pyroptosis and cytokine secretion are the two main mechanisms that occur downstream of inflammasome signaling; they maintain homeostasis, drive the innate immune response, and shape adaptive immunity. This review aims to discuss the possible mechanisms, timing, consequences, and significance of the two uncoupling preferences downstream of inflammasome signaling. While pyroptosis and cytokine secretion may be usually coupled, pyroptosis-predominant and cytokine-predominant uncoupling are also observed in a stimulus-, cell type-, or context-dependent manner, contributing to the pathogenesis and development of numerous pathological conditions such as cryopyrin-associated periodic syndromes, LPS-induced sepsis, and Salmonella enterica serovar Typhimurium infection. Hyperactive cells consistently release IL-1β without LDH leakage and pyroptotic death, thereby leading to prolonged inflammation, expanding the lifespans of pyroptosis-resistant neutrophils, and hyperactivating stimuli-challenged macrophages, dendritic cells, monocytes, and specific nonimmune cells. Death inflammasome activation also induces GSDMD-mediated pyroptosis with no IL-1β secretion, which may increase lethality in vivo. The sublytic GSDMD pore formation associated with lower expressions of pyroptotic components, GSDMD-mediated extracellular vesicles, or other GSDMD-independent pathways that involve unconventional secretion could contribute to the cytokine-predominant uncoupling; the regulation of caspase-1 dynamics, which may generate various active species with different activities in terms of GSDMD or pro-IL-1β, could lead to pyroptosis-predominant uncoupling. These uncoupling preferences enable precise reactions to different stimuli of different intensities under specific conditions at the single-cell level, promoting cooperative cell and host fate decisions and participating in the pathogen "game". Appropriate decisions in terms of coupling and uncoupling are required to heal tissues and eliminate threats, and further studies exploring the inflammasome tilt toward pyroptosis or cytokine secretion may be helpful.

The Inflammasomes Adaptor Protein PYCARD Is a Potential Pyroptosis Biomarker Related to Immune Response and Prognosis in Clear Cell Renal Cell Carcinoma

Simple Summary

Inflammation has been recognized as one of the hallmarks of cancers. PYCARD, the adaptor protein of inflammasomes, plays an important role in pyroptosis and apoptosis. However, the function of PYCARD remains unclear in human cancers. Here, we systematically performed a comprehensive analysis of PYCARD expression and its relationship with immunotherapy response and prognosis. We found significant differences in PYCARD expression between tumor and normal tissue, particularly in clear cell renal cell carcinoma. We also found that PYCARD was an unfavorable prognostic factor and was confirmed by external validation cohorts. Exploration of the profound mechanisms of PYCARD might help to identify new therapeutic targets and improve the efficacy of immunotherapy.

Abstract

PYCARD is a protein engaged in inflammation, pyroptosis, and apoptosis. However, the function of PYCARD in human cancers remains unclear. The objective of our study was to explore PYCARD expression and prognostic value in human cancers. Public databases were used to assess PYCARD expression and prognostic value. The TISIDB database was used to explore the associations between PYCARD expression and different immune subtypes. The correlations between PYCARD expression and ICP genes, MMR genes, MSI, and TMB were also investigated. The immunotherapy response was assessed using the TIDE database. Single-cell RNA databases evaluated the PYCARD expression of immune cells. External datasets and immunohistochemical staining were conducted to validate PYCARD expression and prognostic value. The results showed that PYCARD expression varied in several cancers and was associated with prognosis, immune-related genes, published biomarkers, and immunotherapy response. Of note, PYCARD expression was upregulated in renal cancers with high diagnostic ability. Upregulation of PYCARD was correlated with worse prognosis in KIRC and external validation cohorts. In conclusion, PYCARD demonstrated strong correlations with prognosis, immune response, and disease progression in pan-cancer analysis. In ccRCC, PYCARD might serve as a biomarker for diagnosis and therapeutic target-boosting immunotherapy response.

Downstream Signaling of Inflammasome Pathway Affects Patients' Outcome in the Context of Distinct Molecular Breast Cancer Subtypes

Inflammasomes are protein complexes involved in the regulation of different biological conditions. Over the past few years, the role of NLRP3 in different tumor types has gained interest. In breast cancer (BC), NLRP3 has been associated with multiple processes including epithelia mesenchymal transition, invasion and metastization. Little is known about molecular modifications of NLRP3 up-regulation. In this study, in a cohort of BCs, the expression levels of NLRP3 and PYCARD were analyzed in combination with CyclinD1 and MYC ones and their gene alterations. We described a correlation between the NLRP3/PYCARD axis and CyclinD1 (p < 0.0001). NLRP3, PYCARD and CyclinD1’s positive expression was observed in estrogen receptor (ER) and progesterone receptor (PgR) positive cases (p < 0.0001). Furthermore, a reduction of NLRP3 and PYCARD expression has been observed in triple negative breast cancers (TNBCs) with respect to the Luminal phenotypes (p = 0.017 and p = 0.0015, respectively). The association NLRP3+/CCND1+ or PYCARD+/CCND1+ was related to more aggressive clinicopathological characteristics and a worse clinical outcome, both for progression free survival (PFS) and overall survival (OS) with respect to NLRP3+/CCND1− or PYCARD+/CCND1− patients, both in the whole cohort and also in the subset of Luminal tumors. In conclusion, our study shows that the NLRP3 inflammasome complex is down-regulated in TNBC compared to the Luminal subgroup. Moreover, the expression levels of NLRP3 and PYCARD together with the alterations of CCND1 results in Luminal subtype BC’ss poor prognosis.