ABSTRACT
The cytosolic protein rubicon (RUBCN) has been implicated in the removal of necrotic debris and autoimmunity. However, the role of RUBCN in models of acute kidney injury (AKI), a condition that typically involves necrotic kidney tubules, was not investigated. Here, we demonstrate that RUBCN-deficient mice are hypersensitive to renal damage induced by ischemia-reperfusion injury (IRI) and cisplatin-induced AKI. Combined deficiency of RUBCN and mixed lineage kinase domain-like (MLKL) partially reversed the sensitivity in the IRI model suggesting that the absence of RUBCN sensitizes to necroptosis in that model. Necroptosis is known to contribute to TNFα-induced severe inflammatory response syndrome (SIRS), but we detected no statistically significant difference in overall survival following injection of TNFα in RUBCN-deficient mice. We additionally generated RUBCN-deficient mice which lack gasdermin D (GSDMD), the terminal mediator of pyroptosis, but no reversal of the AKI phenotype was observed. Finally, and in contrast to the previous understanding of the role of RUBCN, we did not find a significant autoimmune phenotype in RUBCN-deficient mice, but detected chronic kidney injury (CKD) in aged RUBCN-deficient mice of both sexes. In summary, our data indicate that RUBCN-deficient mice are hypersensitive to kidney injury.
Subject(s)
Acute Kidney Injury , Reperfusion Injury , Acute Kidney Injury/chemically induced , Acute Kidney Injury/genetics , Animals , Female , Intracellular Signaling Peptides and Proteins/metabolism , Kidney/metabolism , Kidney Tubules/metabolism , Male , Mice , Mice, Inbred C57BL , Protein Kinases/metabolism , Receptor-Interacting Protein Serine-Threonine Kinases/metabolism , Reperfusion Injury/genetics , Reperfusion Injury/metabolism , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Toxoplasma gondii (TG) infection has been reported to be more frequent in schizophrenia. The interaction of the lifelong persisting parasite with the host's immune system involves T-cell/interferon-gamma-induced degradation of tryptophan and provides a challenge to the host well beyond a possible role in the etiology of schizophrenia. The hypothesis we tested in this study was that TG infection may be more frequent (serofrequency) and/or more intense (serointensity) in patients with schizophrenia or major depression compared with psychiatrically healthy controls. In addition, these measures are associated with the clinical course. We did a cross-sectional, prospective investigation of individuals with schizophrenia (n = 277) and major depression (n = 465) admitted to our department (2002-2005) and of healthy controls (n = 214), with all groups adjusted for age and geographic home region. Serofrequency was comparable between the groups, but serointensity was significantly higher in the patients. In individuals with schizophrenia, serointensity was significantly positively associated with C-reactive protein levels and leukocyte counts, and first-episode patients yielded significantly higher serotiters. Immunomodulatory medication was associated with decreased serotiters. In addition, the route of infection appears to differ between patients and controls. Thus, our results support increased host responses to TG infection in the patients, as well as increased titers in first-episode patients with schizophrenia; this may relate to the shifted T-helper 1/2 status described in these patients. Therefore, we suggest that TG infection, particularly in individuals with schizophrenia, is an important environmental factor in the interaction between psychiatric vulnerability, genetic background, immunomodulation, and the neurotransmitter systems.
