Does NLRP1 Inflammasome Activation in Immune Cells in Kidney Transplantation Relate with Donor Organ Age?

Inflammation causes a wide range of health disorders. In this process, the formation of inflammasome complexes plays a key role. Although inflammasomes have been extensively studied during kidney disease, their role in kidney transplantation has not been fully elucidated. In this study, we evaluate the gene and protein expression of several components of the inflammasome pathway before and at several time points after kidney transplantation in a cohort of patients of different ages and receiving an organ from older or younger donors. Our findings indicate the activation of the NLRP1 inflammasome in several immune cell population, monocytes and CD4+ and CD8+ cells mainly, in renal transplant, and its level increases gradually in patients who receive an older organ, whereas it has the opposite effect on older patients who receive a younger organ. Despite treatment with immunosuppressants, inflammation persists in some patients. These results lead to the hypothesis that the donor's age is a critical factor in post-transplant inflammasome activation and that specific NLRP1 inflammasome inhibitors should be considered to increase the success of kidney transplantation long-term.

Does Donor Age Have Effects on Senescence Biomarkers in Kidney-Transplanted Patients?

Renal transplantation is an effective treatment for severe chronic kidney diseases. However, young patients often face a scarcity of kidneys from donors of similar age, resulting in the transplantation of older organs, which increase the risk of graft rejection and several complications compared with older individuals who receive kidneys from donors of similar age or younger. This article focuses on studying different senescence biomarkers in donors and patients who received kidneys from various age ranges complying with the STROBE requirements. We studied 61 patients subjected to renal transplant isolating blood samples 24 h before, and 24 h, 3 days, 7 days, 3 months, and 6 months after transplant. The patients were divided into three groups: older donor than the patient (Old Donor), younger donor than the patient (Young Donor), and similar age (Matched). We studied different senescence markers such as p16, p21, interleukin 6 (IL-6), and senescence-associated secretory phenotype (SASP) release. Young patients who receive older organs showed increased mRNA and protein expression of the senescence makers. Hence, increased SASP release was also observed in patients from older donor. In contrast, older patients who receive younger organs showed a slow but consistent improvement in their initial senescent phenotype. In addition, macrophage cell model treated with blood-derived serum from patients 6 months after the transplant showed a pro-senescence environment in macrophages proposed by the SASP from the patients. These results lead the hypothesis that senolytics could reduce the presence of senescent cells and mitigate the complications associated with the transplantation of older organs in young patients.

Altered insulin secretion dynamics relate to oxidative stress and inflammasome activation in children with obesity and insulin resistance.

BACKGROUND: Insulin resistance (IR) is considered the main driver of obesity related metabolic complications, and is related to oxidative stress and inflammation, which in turn promote each other. There is currently no specific definition of IR in children, rather, that for adult population is used by pediatric endocrinologists instead. Altered insulin secretion dynamics are associated with worse metabolic profiles and type 2 diabetes mellitus development, thus we aimed to test whether insulin response relates to oxidative stress and inflammation in children. METHODS: We conducted a case-control study, including 132 children classified as follows: 33 children without obesity (Lean); 42 with obesity but no IR according to the American Diabetes Association criteria for adults (OBIR-); 25 with obesity and IR and an early insulin response to an oral glucose tolerance test (OGTT) (EP-OBIR +); 32 with obesity, IR, and a late insulin peak (LP-OBIR +); and studied variables associated with lipid and carbohydrate metabolism, oxidative stress, inflammation and inflammasome activation. RESULTS: The measured parameters of children with obesity, IR, and an early insulin response were similar to those of children with obesity but without IR. It was late responders who presented an impaired antioxidant system and elevated oxidative damage in erythrocytes and plasma, and inflammasome activation at their white blood cells, despite lower classical inflammation markers. Increased uric acid levels seems to be one of the underlying mechanisms for inflammasome activation. CONCLUSIONS: It is insulin response to an OGTT that identifies children with obesity suffering oxidative stress and inflammasome activation more specifically. Uric acid could be mediating this pathological inflammatory response by activating NLRP3 in peripheral blood mononuclear cells.

Neurodegeneration, Mitochondria, and Antibiotics.

Neurodegenerative diseases are characterized by the progressive loss of neurons, synapses, dendrites, and myelin in the central and/or peripheral nervous system. Actual therapeutic options for patients are scarce and merely palliative. Although they affect millions of patients worldwide, the molecular mechanisms underlying these conditions remain unclear. Mitochondrial dysfunction is generally found in neurodegenerative diseases and is believed to be involved in the pathomechanisms of these disorders. Therefore, therapies aiming to improve mitochondrial function are promising approaches for neurodegeneration. Although mitochondrial-targeted treatments are limited, new research findings have unraveled the therapeutic potential of several groups of antibiotics. These drugs possess pleiotropic effects beyond their anti-microbial activity, such as anti-inflammatory or mitochondrial enhancer function. In this review, we will discuss the controversial use of antibiotics as potential therapies in neurodegenerative diseases.

NLRP1 inflammasome modulates senescence and senescence-associated secretory phenotype.

Senescence is a cellular aging-related process triggered by different stresses and characterized by the secretion of various inflammatory factors referred to as the senescence-associated secretory phenotype (SASP). Here, we present evidence that the inflammasome sensor, NLRP1, is a key mediator of senescence induced by irradiation both in vitro and in vivo. The NLRP1 inflammasome promotes senescence by regulating the expression of p16, p21, p53, and SASP in Gasdermin D (GSDMD)-dependent manner as these responses are reduced in conditions of NLRP1 insufficiency or GSDMD inhibition. Mechanistically, the NLRP1 inflammasome is activated downstream of the cytosolic DNA sensor cGMP-AMP (cGAMP) synthase (cGAS) in response to genomic damage. These findings provide a rationale for inhibiting the NLRP1 inflammasome-GSDMD axis to treat senescence-driven disorders.