Talaromyces marneffei activates the AIM2-caspase-1/-4-GSDMD axis to induce pyroptosis in hepatocytes

The role and mechanisms of PD-L1 in immune evasion during Talaromyces marneffei infection

Talaromycosis, caused by Talaromyces marneffei (T. marneffei), is a systemic fungal disease that involves dissemination throughout the body. The ability of T. marneffei to evade the immune system is considered a crucial factor in its persistent infection, although the specific mechanisms are not yet fully understood. This study aims to investigate the molecular mechanisms underlying the occurrence of latent T. marneffei infection and immune evasion. The gene expression profile analysis in T. marneffei-infected mouse revealed that Pd-l1 exhibited the highest correlation strength with other hub genes, with a median of 0.60 (IQR: 0.50-0.69). T. marneffei infection upregulated the expression of PD-1 and PD-L1 in PBMCs from HIV patients, which was also observed in the T. marneffei-infected mouse and macrophage models. Treatment with a PD-L1 inhibitor significantly reduced fungal burden in the liver and spleen tissues of infected mice and in the kupffer-CTLL-2 co-culture system. PD-L1 inhibitor treatment increased CTLL-2 cell proliferation and downregulated the expression of PD-1, SHP-2, and p-SHP-2, indicating the activation of T cell viability and T cell receptor signaling pathway. Additionally, treatment with a PI3K inhibitor downregulated PD-L1 in T. marneffei-infected kupffer cells. Similar results were observed with treatment using the T. marneffei cell wall virulence factor β-glucan. Overall, T. marneffei infection upregulated PD-L1 expression in HIV / T. marneffei patients, mice, and kupffer cells. Treatment with a PD-L1 inhibitor significantly reduced fungal burden, while activating T cell activity and proliferation, thereby promoting fungal clearance. Furthermore, the PI3K signaling pathway may be involved in the regulation of PD-L1 by T. marneffei.

Aspartate Aminotransferase/Platelet Ratio Index Upon Admission Predicts 24-Week Mortality in Patients With HIV-Associated Talaromyces marneffei

Background

A high aspartate aminotransferase/platelet ratio index (APRI) predicts mortality in patients with severe infection. This study aims to assess the potential of APRI as a predictor for mortality in patients with HIV-associated Talaromyces marneffei (HTM).

Methods

Associations between APRI and CD4 count, white blood cell count, C-reactive protein (CRP) level, procalcitonin (PCT) level, and cytokines were assessed in 119 patients. Univariate and multivariate Cox regression models were used to predict APRI on 24-week mortality.

Results

APRI was positively associated with CRP (r = 0.190, P = .039), PCT (r = 0.220, P = .018), interleukin 6 (r = 0.723, P < .001), interleukin 10 (r = 0.416, P = .006), and tumor necrosis factor α (r = 0.575, P < .001) and negatively associated with CD4 count (r = -0.234, P = .011). In total, 20.2% (24/119) of patients died within the 24-week follow-up. The 24-week survival rate was 88.0% for patients with APRI <5.6% and 61.1% for those with APRI ≥5.6 (log-rank P < .001). After adjustment for sex, age, body mass index, and CD4 count, as well as serum levels of hemoglobin, APRI ≥5.6 (adjusted hazard ratio [95% CI]; 3.0 [1.2-7.1], P = .015), PCT ≥1.7 ng/mL (3.7 [1.5-9.6], P = .006), and non-amphotericin B deoxycholate treatment (2.8 [1.2-6.6], P = .018) were independent risk factors for 24-week mortality.

Conclusions

For patients with HTM, APRI is associated with severity and is an independent risk factor for 24-week mortality.

Recent advances in pyroptosis, liver disease, and traditional Chinese medicine: A review

In recent years, the incidence of liver disease has increased, becoming a major cause of death. Various liver diseases are intricately linked to pyroptosis, which is one of the most common forms of programmed cell death. As a powerful weapon in the fight against liver diseases, traditional Chinese medicine (TCM) can affect pyroptosis via a number of routes, including the classical, nucleotide oligomerization domain-like receptors protein 3/caspase-1/gasdermin D (GSDMD) pathway, the nonclassical lipopolysaccharide/caspase-11/GSDMD pathway, the ROS/caspase-3/gasdermin E pathway, the caspase-9/caspase-3/GSDMD pathway, and the Apaf-1/caspase-11/caspase-3 pathway. In this review, we provide an overview of pyroptosis, the interplay between pyroptosis and liver diseases, and the mechanisms through which TCM regulates pyroptosis in liver diseases. The information used in the text was collected and compiled from the databases of PubMed, Web of Science, Scopus, CNKI, and Wanfang Data up to June 2023. The search was not limited with regard to the language and country of the articles. Research and review articles were included, and papers with duplicate results or unrelated content were excluded. We examined the current understanding of the relationship between pyroptosis and liver diseases as well as the advances in TCM interventions to provide a resource for the identification of potential targets for TCM in the treatment of liver diseases.

Construction of a murine model of latent infection and reactivation induced by Talaromyces marneffei

OBJECTIVE

To establish a murine model of Talaromyces marneffei (T. marneffei) latent infection and reactivation, providing a foundation for exploring the molecular mechanisms underlying disease relapse.

METHODS

BALB/c mice were tail vein injected with T. marneffei at 0 days post-infection (dpi) and treated with cyclophosphamide (CTX) intraperitoneally every four days, starting from 21 dpi or 42 dpi. Mice were observed for body weight changes, liver and spleen indices, histological characteristics of liver and spleen, fungal load detection in liver and spleen, and Mp1p qualitation in liver and spleen to assess T. marneffei infection severity.

RESULTS

T. marneffei-infected mice exhibited a trend of initial weight loss followed by recovery and a subsequent decrease in weight after CTX injection throughout the observation period. Liver and spleen indices, as well as tissue damage, significantly increased during infection but later returned to normal levels, with a gradual rise observed after immunosuppression. Fungal load analysis revealed positive T. marneffei cultures in the liver and spleen at 7 dpi and 14 dpi, followed by negative T. marneffei cultures from 21 dpi until day 21 post-immunosuppression (42 dpi or 63 dpi); however, the spleen remained T. marneffei-cultured negative, consistent with the trend observed in Mp1p detection results.

CONCLUSION

A latent infection and reactivation model of T. marneffei in mice was successfully established, with the liver likely serving as a key site for latent T. marneffei.

GAS5-inhibited hepatocyte pyroptosis contributes to hepatic stellate cell inactivation via microRNA-684 and AHR

Hepatocyte pyroptosis has been shown to be involved in liver damage progression. Previously, we found that growth arrest-specific 5 (GAS5) is a regulator of hepatic stellate cell (HSC) activation. However, whether GAS5 plays a role in hepatocyte pyroptosis remains unclear. In this study, reduced GAS5 was shown in CCl₄-treated mice and restoration of GAS5-inhibited liver fibrosis in vivo. Hepatocyte pyroptosis participated in the effects of GAS5-inhibited liver fibrosis, associated with reduced caspase-1, NLRP3, and IL-1β (hepatocyte pyroptosis markers). Notably, AHR expression, a suppressor of NLRP3, was enhanced by GAS5. Silencing AHR inhibited GAS5-mediated hepatocyte pyroptosis. GAS5 and AHR were targets of microRNA-684 (miR-684). In addition, the effects of GAS5 on hepatocyte pyroptosis could be inhibited by miR-684. Interestingly, GAS5-mediated hepatocyte pyroptosis contributed to HSC inactivation. In conclusion, we demonstrate that GAS5 inhibits hepatocyte pyroptosis and HSC activation, at least in part, via regulation of miR-684 and AHR.

An Overlooked and Underrated Endemic Mycosis-Talaromycosis and the Pathogenic Fungus Talaromyces marneffei

Talaromycosis is an invasive mycosis endemic in tropical and subtropical Asia and is caused by the pathogenic fungus Talaromyces marneffei. Approximately 17,300 cases of T. marneffei infection are diagnosed annually, and the reported mortality rate is extremely high (~1/3). Despite the devastating impact of talaromycosis on immunocompromised individuals, particularly HIV-positive persons, and the increase in reported occurrences in HIV-uninfected persons, diagnostic and therapeutic approaches for talaromycosis have received far too little attention worldwide. In 2021, scientists living in countries where talaromycosis is endemic raised a global demand for it to be recognized as a neglected tropical disease. Therefore, T. marneffei and the infectious disease induced by this fungus must be treated with concern. T. marneffei is a thermally dimorphic saprophytic fungus with a complicated mycological growth process that may produce various cell types in its life cycle, including conidia, hyphae, and yeast, all of which are associated with its pathogenicity. However, understanding of the pathogenic mechanism of T. marneffei has been limited until recently. To achieve a holistic view of T. marneffei and talaromycosis, the current knowledge about talaromycosis and research breakthroughs regarding T. marneffei growth biology are discussed in this review, along with the interaction of the fungus with environmental stimuli and the host immune response to fungal infection. Importantly, the future research directions required for understanding this serious infection and its causative pathogenic fungus are also emphasized to identify solutions that will alleviate the suffering of susceptible individuals worldwide.

Identification of SSBP1 as a ferroptosis-related biomarker of glioblastoma based on a novel mitochondria-related gene risk model and in vitro experiments

Background

Glioblastoma (GBM) is the most common primary malignant brain tumor that leads to lethality. Several studies have demonstrated that mitochondria play an important role in GBM and that mitochondria-related genes (MRGs) are potential therapeutic targets. However, the role of MRGs in GBM remains unclear.

Methods

Differential expression and univariate Cox regression analyses were combined to screen for prognostic differentially-expressed (DE)-MRGs in GBM. Based on LASSO Cox analysis, 12 DE-MRGs were selected to construct a risk score model. Survival, time dependent ROC, and stratified analyses were performed to evaluate the performance of this risk model. Mutation and functional enrichment analyses were performed to determine the potential mechanism of the risk score. Immune cell infiltration analysis was used to determine the association between the risk score and immune cell infiltration levels. CCK-8 and transwell assays were performed to evaluate cell proliferation and migration, respectively. Mitochondrial reactive oxygen species (ROS) levels and morphology were measured using a confocal laser scanning microscope. Genes and proteins expression levels were investigated by quantitative PCR and western blotting, respectively.

Results

We identified 21 prognostic DE-MRGs, of which 12 DE-MRGs were selected to construct a prognostic risk score model for GBM. This model presented excellent performance in predicting the prognosis of patients with GBM and acted as an independent predictive factor. Functional enrichment analysis revealed that the risk score was enriched in the inflammatory response, extracellular matrix, and pro-cancer-related and immune related pathways. Additionally, the risk score was significantly associated with gene mutations and immune cell infiltration in GBM. Single-stranded DNA-binding protein 1 (SSBP1) was considerably upregulated in GBM and associated with poor prognosis. Furthermore, SSBP1 knockdown inhibited GBM cell progression and migration. Mechanistically, SSBP1 knockdown resulted in mitochondrial dysfunction and increased ROS levels, which, in turn, increased temozolomide (TMZ) sensitivity in GBM cells by enhancing ferroptosis.

Conclusion

Our 12 DE-MRGs-based prognostic model can predict the GBM patients prognosis and 12 MRGs are potential targets for the treatment of GBM. SSBP1 was significantly upregulated in GBM and protected U87 cells from TMZ-induced ferroptosis, which could serve as a prognostic and therapeutic target/biomarker for GBM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03657-4.

Evidence of pyroptosis and ferroptosis extensively involved in autoimmune diseases at the single-cell transcriptome level

BACKGROUND

Approximately 8-9% of the world's population is affected by autoimmune diseases, and yet the mechanism of autoimmunity trigger is largely understudied. Two unique cell death modalities, ferroptosis and pyroptosis, provide a new perspective on the mechanisms leading to autoimmune diseases, and development of new treatment strategies.

METHODS

Using scRNA-seq datasets, the aberrant trend of ferroptosis and pyroptosis-related genes were analyzed in several representative autoimmune diseases (psoriasis, atopic dermatitis, vitiligo, multiple sclerosis, systemic sclerosis-associated interstitial lung disease, Crohn's disease, and experimental autoimmune orchitis). Cell line models were also assessed using bulk RNA-seq and qPCR.

RESULTS

A substantial difference was observed between normal and autoimmune disease samples involving ferroptosis and pyroptosis. In the present study, ferroptosis and pyroptosis showed an imbalance in different keratinocyte lineages of psoriatic skinin addition to a unique pyroptosis-sensitive keratinocyte subset in atopic dermatitis (AD) skin. The results also revealed that pyroptosis and ferroptosis are involved in epidermal melanocyte destruction in vitiligo. Aberrant ferroptosis has been detected in multiple sclerosis, systemic sclerosis-associated interstitial lung disease, Crohn's disease, and autoimmune orchitis. Cell line models adopted in the study also identified pro-inflammatory factors that can drive changes in ferroptosis and pyroptosis.

CONCLUSION

These results provide a unique perspective on the involvement of ferroptosis and pyroptosis in the pathological process of autoimmune diseases at the scRNA-seq level. IFN-γ is a critical inducer of pyroptosis sensitivity, and has been identified in two cell line models.