Molecular changes associated with increased TNF-α-induced apoptotis in naïve (TN) and central memory (TCM) CD8+ T cells in aged humans

Excessive apoptosis of Rip1-deficient T cells leads to premature aging

In mammals, the most remarkable T cell variations with aging are the shrinking of the naïve T cell pool and the enlargement of the memory T cell pool, which are partially caused by thymic involution. However, the mechanism underlying the relationship between T-cell changes and aging remains unclear. In this study, we find that T-cell-specific Rip1 KO mice show similar age-related T cell changes and exhibit signs of accelerated aging-like phenotypes, including inflammation, multiple age-related diseases, and a shorter lifespan. Mechanistically, Rip1-deficient T cells undergo excessive apoptosis and promote chronic inflammation. Consistent with this, blocking apoptosis by co-deletion of Fadd in Rip1-deficient T cells significantly rescues lymphopenia, the imbalance between naïve and memory T cells, and aging-like phenotypes, and prolongs life span in T-cell-specific Rip1 KO mice. These results suggest that the reduction and hyperactivation of T cells can have a significant impact on organismal health and lifespan, underscoring the importance of maintaining T cell homeostasis for healthy aging and prevention or treatment of age-related diseases.

A peptide derived from HSP60 reduces proinflammatory cytokines and soluble mediators: a therapeutic approach to inflammation

Cytokines are secretion proteins that mediate and regulate immunity and inflammation. They are crucial in the progress of acute inflammatory diseases and autoimmunity. In fact, the inhibition of proinflammatory cytokines has been widely tested in the treatment of rheumatoid arthritis (RA). Some of these inhibitors have been used in the treatment of COVID-19 patients to improve survival rates. However, controlling the extent of inflammation with cytokine inhibitors is still a challenge because these molecules are redundant and pleiotropic. Here we review a novel therapeutic approach based on the use of the HSP60-derived Altered Peptide Ligand (APL) designed for RA and repositioned for the treatment of COVID-19 patients with hyperinflammation. HSP60 is a molecular chaperone found in all cells. It is involved in a wide diversity of cellular events including protein folding and trafficking. HSP60 concentration increases during cellular stress, for example inflammation. This protein has a dual role in immunity. Some HSP60-derived soluble epitopes induce inflammation, while others are immunoregulatory. Our HSP60-derived APL decreases the concentration of cytokines and induces the increase of FOXP3+ regulatory T cells (Treg) in various experimental systems. Furthermore, it decreases several cytokines and soluble mediators that are raised in RA, as well as decreases the excessive inflammatory response induced by SARS-CoV-2. This approach can be extended to other inflammatory diseases.

Multidimensional single-cell analysis of human peripheral blood reveals characteristic features of the immune system landscape in aging and frailty

Frailty is an intermediate status of the human aging process, associated with decompensated homeostasis and death. The immune phenotype of frailty and its underlying cellular and molecular processes remain poorly understood. We profiled 114,467 immune cells from cord blood, young adults and healthy and frail old adults using single-cell RNA and TCR sequencing. Here we show an age-dependent accumulation of transcriptome heterogeneity and variability in immune cells. Characteristic transcription factors were identified in given cell types of specific age groups. Trajectory analysis revealed cells from non-frail and frail old adults often fall into distinct paths. Numerous TCR clonotypes were shared among T-cell subtypes in old adults, indicating differential pluripotency and resilience capabilities of aged T cells. A frailty-specific monocyte subset was identified with exclusively high expression of long noncoding RNAs NEAT1 and MALAT1. Our study discovers human frailty-specific immune cell characteristics based on the comprehensive dimensions in the immune landscape of aging and frailty.

Systems approaches to investigate the role of NF-κB signaling in aging

The nuclear factor-κB (NF-κB) signaling pathway is one of the most well-studied pathways related to inflammation, and its involvement in aging has attracted considerable attention. As aging is a complex phenomenon and is the result of a multi-step process, the involvement of the NF-κB pathway in aging remains unclear. To elucidate the role of NF-κB in the regulation of aging, different systems biology approaches have been employed. A multi-omics data-driven approach can be used to interpret and clarify unknown mechanisms but cannot generate mechanistic regulatory structures alone. In contrast, combining this approach with a mathematical modeling approach can identify the mechanistics of the phenomena of interest. The development of single-cell technologies has also helped clarify the heterogeneity of the NF-κB response and underlying mechanisms. Here, we review advances in the understanding of the regulation of aging by NF-κB by focusing on omics approaches, single-cell analysis, and mathematical modeling of the NF-κB network.

Geraniin inhibits whole blood IFN-γ and IL-6 and promotes IL-1β and IL-8, and stimulates calcium-dependent and sucrose-sensitive erythrocyte death

Correlations between circulating cytokine levels and disease states are well established, and pharmacological modulation of the immune response is thus an important aspect of the assessment of investigational new drugs. Moreover, chemotherapy-related anemia is a major obstacle in cancer treatment. Geraniin (GRN), a tannin extracted from Geranium and other plants, possesses promising antitumor potential. However, the effect of GRN on whole blood (WB) cytokine response and RBC physiology remains unexplored. Heparinized blood from consented, healthy adults was challenged with 100 ng/mL of lipopolysaccharide (LPS) with and without pretreatment with 10 μM of GRN for 24 h at 37 °C, and tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-6, IL-8, and IL-10 were assayed by ELISA. Moreover, single-cell RBC suspensions were treated with 5-100 μM of GRN for 24 or 48 h at 37 °C and cytotoxicity and canonical eryptotic markers were examined by flow cytometry. It was revealed that GRN significantly attenuated LPS-induced IFN-γ levels, increased IL-1β, decreased IL-6 only in absence of LPS, and aggravated LPS-induced IL-8 while together with LPS significantly diminished IL-10. Furthermore, GRN induced dose-responsive, Ca²⁺-dependent, and sucrose-sensitive hemolysis, along with phosphatidylserine exposure and Ca²⁺ accumulation with no appreciable cell shrinkage or oxidative damage. GRN was also selectively toxic to platelets, significantly delayed reticulocyte maturation, and significantly disrupted leukocyte proportions. In conclusion, GRN regulates the WB cytokine response and promotes premature hemolysis and eryptosis. This study provides insights into the therapeutic utility of GRN in a highly relevant cellular model system.

A single-cell map for the transcriptomic signatures of peripheral blood mononuclear cells in end-stage renal disease

BACKGROUND

Immune aberrations in end-stage renal disease (ESRD) are characterized by systemic inflammation and immune deficiency. The mechanistic understanding of this phenomenon remains limited.

METHODS

We generated 12 981 and 9578 single-cell transcriptomes of peripheral blood mononuclear cells (PBMCs) that were pooled from 10 healthy volunteers and 10 patients with ESRD by single-cell RNA sequencing. Unsupervised clustering and annotation analyses were performed to cluster and identify cell types. The analysis of hallmark pathway and regulon activity was performed in the main cell types.

RESULTS

We identified 14 leukocytic clusters that corresponded to six known PBMC types. The comparison of cells from ESRD patients and healthy individuals revealed multiple changes in biological processes. We noticed an ESRD-related increase in inflammation response, complement cascade and cellular metabolism, as well as a strong decrease in activity related to cell cycle progression in relevant cell types in ESRD. Furthermore, a list of cell type-specific candidate transcription factors (TFs) driving the ESRD-associated transcriptome changes was identified.

CONCLUSIONS

We generated a distinctive, high-resolution map of ESRD-derived PBMCs. These results revealed cell type-specific ESRD-associated pathways and TFs. Notably, the pooled sample analysis limits the generalization of our results. The generation of larger single-cell datasets will complement the current map and drive advances in therapies that manipulate immune cell function in ESRD.

Effects of oral environment on frailty: particular relevance of tongue pressure

Purpose

Oral frailty or the loss of oral functionality can be a symptomatic precursor of overall frailty. Previous studies have suggested that decreased tongue pressure causes a decline in ingesting and swallowing function and poor nutrition. This study investigated what factor(s) contribute to tongue pressure, thereby leading to frailty.

Patients and methods

For the purposes of the present study, 467 residents of Hirosaki city in northern Japan aged≥60 years who completed a questionnaire about frailty and underwent an intraoral assessment, which included number of teeth, presence or absence of periodontitis, tongue pressure, and oral diadochokinesis (ODK) were recruited.

Results

Of the 467 participants with complete data sets, frailty was identified in 13 (7.5%) of 173 males and in 34 (11.6%) of 294 females. Significantly fewer teeth, lower tongue pressure, and a reduced diadochokinetic syllable rate were more prevalent among frail than among healthy residents. Multivariable logistic regression analysis revealed that age, body mass index, number of teeth, and tongue pressure significantly contributed to frailty, whereas ODK did not. Multiple regression analysis showed that tongue pressure was positively associated with muscle index and number of teeth.

Conclusion

The results of the present study suggest that fewer teeth and lower tongue pressure, but not ODK function, are risk factors for developing overall frailty among older residents.