CISH impairs lysosomal function in activated T cells resulting in mitochondrial DNA release and inflammaging

Analysis of Cytokine-Inducible SH2-Containing Protein (CISH) in the Study of Immunosenescence

The aging immune system undergoes significant changes, leading to a state known as immunosenescence. Understanding the molecular mechanisms underlying immunosenescence is crucial for developing targeted interventions to enhance immune functions in older individuals. This bio-protocol review focuses on the application of quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for the mRNA quantification of cytokine-inducible SH2-containing protein (CISH), an immune regulator overexpressed in T-cell responses from older adults. We outline a comprehensive protocol for the quantitative assessment of CISH mRNA expression, providing a valuable tool for researchers investigating immunosenescence.

Immune aging and infectious diseases

ABSTRACT

The rise in global life expectancy has led to an increase in the older population, presenting significant challenges in managing infectious diseases. Aging affects the innate and adaptive immune systems, resulting in chronic low-grade inflammation (inflammaging) and immune function decline (immunosenescence). These changes would impair defense mechanisms, increase susceptibility to infections and reduce vaccine efficacy in older adults. Cellular senescence exacerbates these issues by releasing pro-inflammatory factors, further perpetuating chronic inflammation. Moreover, comorbidities, such as cardiovascular disease and diabetes, which are common in older adults, amplify immune dysfunction, while immunosuppressive medications further complicate responses to infections. This review explores the molecular and cellular mechanisms driving inflammaging and immunosenescence, focusing on genomic instability, telomere attrition, and mitochondrial dysfunction. Additionally, we discussed how aging-associated immune alterations influence responses to bacterial, viral, and parasitic infections and evaluated emerging antiaging strategies, aimed at mitigating these effects to improve health outcomes in the aging population.

Metabolic checkpoints in rheumatoid arthritis

BACKGROUND

Rheumatoid Arthritis is a systemic autoimmune disease affecting 0.5-1 % of the population. Despite a growing therapeutic armamentarium, RA remains incurable, and many patients suffer significant morbidity over time. The strongest genetic risk derives from HLA class II polymorphisms, implicating T cells as pathogenic drivers. Innate immune cells, e.g. monocytes and macrophages (Mⱷ) contribute to chronic tissue inflammation through an array of pro-inflammatory functions but also present antigen to autoreactive T cells. Differentiation, survival, and effector functions of both T cells and Mⱷ are ultimately controlled by their bioenergetic and biosynthetic programs, identifying cellular metabolism as a critical disease mechanism in RA.

OBJECTIVES

Summarize current knowledge about metabolic conditions in the RA joint and disease-relevant metabolic circuits shaping the effector repertoire of RA T cells and Mⱷ.

RESULTS

The rheumatoid joint is a glucose deplete tissue environment, selecting for invading immune cells that can survive on non-glucose fuel sources. Inflamed synovium instead offers the amino acid glutamine and RA CD4+T cells and RA Mⱷ rely on glutamine and glutamate to support their pathogenic functions. The metabolic hallmark of RA T cells is their low mitochondrial performance, resulting in low ATP production, low generation of reactive oxygen species (ROS) and low availability of tricarboxylic acid (TCA) cycle intermediates, all shifting RA T cells towards autoreactivity. The underlying defect stems from insufficient repair of mitochondrial DNA (mtDNA). Functional consequences include reversal of the TCA cycle, accumulation of citrate and lack of malate production. Excessive citrate promotes cytoskeletal hyperacetylation, creating hypermigratory and tissue-invasive T cells. Surplus acetyl-CoA supports lipid droplet formation and lipotoxicity. Lack of malate production disrupts the malate-aspartate shuttle, restricts recovery of cytosolic NAD and drives the endoplasmic reticulum (ER) into expansion. The bioenergetically stressed ER accumulates TNF mRNA and turns RA T cells into TNF superproducers. ATP low production renders RA T cells susceptible to cell death, depositing highly inflammatory mtDNA in the tissue. Mitochondrial deficiency leads to a slowdown in glycolysis and pyruvate processing, such that RA CD4+T cells shunt glucose towards the pentose phosphate pathway to support nucleotide synthesis and clonal proliferation. Metabolically deprived CD4+T cells partner with Mⱷ that have highly functional mitochondria. A hallmark of RA Mⱷ is the high expression of the DNA binding protein RFX5, which co-ordinates adaptations to metabolic needs with function. RFX5 upregulates HLA-DR expression and induces the glutaminolytic enzyme glutamate dehydrogenase 1 (GLUD1), providing bioenergetic resources for antigen presentation and survival in the tissue. In essence, RA CD4+T cells and Mⱷ function in a metabolically challenging environment and rewire their cellular metabolism to survive. Metabolic adaptations promote immunostimulation and tissue inflammation, triggering and sustaining rheumatoid synovitis.

Multidimensional profiling of human T cells reveals high CD38 expression, marking recent thymic emigrants and age-related naive T cell remodeling

Thymic involution is a key factor in human immune aging, leading to reduced thymic output and a decline in recent thymic emigrant (RTE) naive T cells in circulation. Currently, the precise definition of human RTEs and their corresponding cell surface markers lacks clarity. Analysis of single-cell RNA-seq/ATAC-seq data distinguished RTEs by the expression of SOX4, IKZF2, and TOX and CD38 protein, whereby surface CD38hi expression universally identified CD8+ and CD4+ RTEs. We further determined the dynamics of RTEs and mature cells in a cohort of 158 individuals, including age-associated transcriptional reprogramming and shifts in cytokine production. Spectral cytometry profiling revealed two axes of aging common to naive CD8+ and CD4+ T cells: (1) a decrease in CD38++ cells (RTEs) and (2) an increase in CXCR3hi cells. Identification of RTEs enables direct assessment of thymic health. Furthermore, resolving the dynamics of naive T cell remodeling yields insight into vaccination and infection responsiveness throughout aging.

Research progress on interferon and cellular senescence

Since the 12 major signs of aging were revealed in 2023, people's interpretation of aging will go further, which is of great significance for understanding the occurrence, development, and intervention in the aging process. As one of the 12 major signs of aging, cellular senescence refers to the process in which the proliferation and differentiation ability of cells decrease under stress stimulation or over time, often manifested as changes in cell morphology, cell cycle arrest, and decreased metabolic function. Interferon (IFN), as a secreted ligand for specific cell surface receptors, can trigger the transcription of interferon-stimulated genes (ISGs) and play an important role in cellular senescence. In addition, IFN serves as an important component of SASP, and the activation of the IFN signaling pathway has been shown to contribute to cell apoptosis and senescence. It is expected to delay cellular senescence by linking IFN with cellular senescence and studying the effects of IFN on cellular senescence and its mechanism. This article provides a review of the research on the relationship between IFN and cellular senescence by consulting relevant literature.

Intracellular acidification and glycolysis modulate inflammatory pathway in senescent cells

Senescent cells accumulate in various organs with ageing, and its accumulation induces chronic inflammation and age-related physiological dysfunctions. Several remodelling of intracellular environments have been identified in senescent cells, including enlargement of cell/nuclear size and intracellular acidification. Although these alterations of intracellular environments were reported to be involved in the unique characteristics of senescent cells, the contribution of intracellular acidification to senescence-associated cellular phenotypes is poorly understood. Here, we identified that the upregulation of TXNIP and its paralog ARRDC4 as a hallmark of intracellular acidification in addition to KGA-type GLS1. These genes were also upregulated in response to senescence-associated intracellular acidification. Neutralization of the intracellular acidic environment ameliorated not only senescence-related upregulation of TXNIP, ARRDC4 and KGA but also inflammation-related genes, possibly through suppression of PDK-dependent anaerobic glycolysis. Furthermore, we found that expression of the intracellular acidification-induced genes, TXNIP and ARRDC4, correlated with inflammatory gene expression in heterogeneous senescent cell population in vitro and even in vivo, implying that the contribution of intracellular pH to senescence-associated cellular features, such as SASP.

Palbociclib-derived multifunctional molecules for lysosomal targeting and diagnostic-therapeutic integration

Aim: Lysosomal pH changes are associated with drug resistance, cell growth and invasion of tumors, but effective and specific real-time monitoring of lysosomal pH compounds for cancer therapy is lacking. Materials & methods: Here, based on the covalent linkage of the anticancer drug palbociclib and fluorescent dye fluorescein isothiocyanate (FITC), we designed and developed a novel palbociclib-derived multifunctional molecule (Pal-FITC) for lysosomal targeting and diagnostic therapeutic integration. Results & discussion: Pal-FITC fluoresces is 20-fold stronger than that of FITC and shows a linear response in the pH range of 4.0-8.2 (R2 = 0.9901). Pal-FITC blocks cells in G1 phase via Cyclin D-CDK4/6-Rb. Conclusion: Our study provides new strategies for tumor-targeted imaging and personalized therapy.

Microfluidic Biochips for Single-Cell Isolation and Single-Cell Analysis of Multiomics and Exosomes

Single-cell multiomic and exosome analyses are potent tools in various fields, such as cancer research, immunology, neuroscience, microbiology, and drug development. They facilitate the in-depth exploration of biological systems, providing insights into disease mechanisms and aiding in treatment. Single-cell isolation, which is crucial for single-cell analysis, ensures reliable cell isolation and quality control for further downstream analyses. Microfluidic chips are small lightweight systems that facilitate efficient and high-throughput single-cell isolation and real-time single-cell analysis on- or off-chip. Therefore, most current single-cell isolation and analysis technologies are based on the single-cell microfluidic technology. This review offers comprehensive guidance to researchers across different fields on the selection of appropriate microfluidic chip technologies for single-cell isolation and analysis. This review describes the design principles, separation mechanisms, chip characteristics, and cellular effects of various microfluidic chips available for single-cell isolation. Moreover, this review highlights the implications of using this technology for subsequent analyses, including single-cell multiomic and exosome analyses. Finally, the current challenges and future prospects of microfluidic chip technology are outlined for multiplex single-cell isolation and multiomic and exosome analyses.

The prognostic significance of ubiquitination-related genes in multiple myeloma by bioinformatics analysis

BACKGROUND

Immunoregulatory drugs regulate the ubiquitin-proteasome system, which is the main treatment for multiple myeloma (MM) at present. In this study, bioinformatics analysis was used to construct the risk model and evaluate the prognostic value of ubiquitination-related genes in MM.

METHODS AND RESULTS

The data on ubiquitination-related genes and MM samples were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. The consistent cluster analysis and ESTIMATE algorithm were used to create distinct clusters. The MM prognostic risk model was constructed through single-factor and multiple-factor analysis. The ROC curve was plotted to compare the survival difference between high- and low-risk groups. The nomogram was used to validate the predictive capability of the risk model. A total of 87 ubiquitination-related genes were obtained, with 47 genes showing high expression in the MM group. According to the consistent cluster analysis, 4 clusters were determined. The immune infiltration, survival, and prognosis differed significantly among the 4 clusters. The tumor purity was higher in clusters 1 and 3 than in clusters 2 and 4, while the immune score and stromal score were lower in clusters 1 and 3. The proportion of B cells memory, plasma cells, and T cells CD4 naïve was the lowest in cluster 4. The model genes KLHL24, HERC6, USP3, TNIP1, and CISH were highly expressed in the high-risk group. AICAr and BMS.754,807 exhibited higher drug sensitivity in the low-risk group, whereas Bleomycin showed higher drug sensitivity in the high-risk group. The nomogram of the risk model demonstrated good efficacy in predicting the survival of MM patients using TCGA and GEO datasets.

CONCLUSIONS

The risk model constructed by ubiquitination-related genes can be effectively used to predict the prognosis of MM patients. KLHL24, HERC6, USP3, TNIP1, and CISH genes in MM warrant further investigation as therapeutic targets and to combat drug resistance.

Molecular mechanisms underlying mitochondrial damage, endoplasmic reticulum stress, and oxidative stress induced by environmental pollutants

Mitochondria and endoplasmic reticulum (ER) are essential organelles playing pivotal roles in the regulation of cellular metabolism, energy production, and protein synthesis. In addition, these organelles are important targets susceptible to external stimuli, such as environmental pollutants. Exposure to environmental pollutants can cause the mitochondrial damage, endoplasmic reticulum stress (ERS), and oxidative stress, leading to cellular dysfunction and death. Therefore, understanding the toxic effects and molecular mechanisms of environmental pollution underlying these processes is crucial for developing effective strategies to mitigate the adverse effects of environmental pollutants on human health. In the present study, we summarized and reviewed the toxic effects and molecular mechanisms of mitochondrial damage, ERS, and oxidative stress caused by exposure to environmental pollutants as well as interactions inducing the cell apoptosis and the roles in exposure to environmental pollutants.

The paradox of aging: Aging-related shifts in T cell function and metabolism

T cell survival, differentiation after stimulation, and function are intrinsically linked to distinct cellular metabolic states. The ability of T cells to readily transition between metabolic states enables flexibility to meet the changing energy demands defined by distinct effector states or T cell lineages. Immune aging is characterized, in part, by the loss of naïve T cells, accumulation of senescent T cells, severe dysfunction in memory phenotype T cells in particular, and elevated levels of inflammatory cytokines, or 'inflammaging'. Here, we review our current understanding of the phenotypic and functional changes that occur with aging in T cells, and how they relate to metabolic changes in the steady state and after T cell activation. We discuss the apparent contradictions in the aging T cell phenotype - where enhanced differentiation states and metabolic profiles in the steady state can correspond to a diminished capacity to adapt metabolically and functionally after T cell activation. Finally, we discuss key recent studies that indicate the enormous potential for aged T cell metabolism to induce systemic inflammaging and organism-wide multimorbidity, resulting in premature death.

T cell fate decisions during memory cell generation with aging

The defense against infectious diseases, either through natural immunity or after vaccinations, relies on the generation and maintenance of protective T cell memory. Naïve T cells are at the center of memory T cell generation during primary responses. Upon activation, they undergo a complex, highly regulated differentiation process towards different functional states. Naïve T cells maintained into older age have undergone epigenetic adaptations that influence their fate decisions during differentiation. We review age-sensitive, molecular pathways and gene regulatory networks that bias naïve T cell differentiation towards effector cell generation at the expense of memory and Tfh cells. As a result, T cell differentiation in older adults is associated with release of bioactive waste products into the microenvironment, higher stress sensitivity as well as skewing towards pro-inflammatory signatures and shorter life spans. These maladaptations not only contribute to poor vaccine responses in older adults but also fuel a more inflammatory state.

Old T cells pollute with mito-litter

The mysteries behind immune aging and its related inflammation are being unmasked. The research of Jin et al. reveals that the defective turnover of damaged mitochondria in CD4+ T cells from aged individuals results in the exacerbated secretion of mitochondrial DNA, fuelling inflammaging and impairing immune responses.