Adaptation to low parasite abundance affects immune investment and immunopathological responses of cavefish
NATURE ECOLOGY & EVOLUTION
Authors: Peuss, Robert; Box, Andrew C.; Chen, Shiyuan; Wang, Yongfu; Tsuchiya, Dai; Persons, Jenna L.; Kenzior, Alexander; Maldonado, Ernesto; Krishnan, Jaya; Scharsack, Joern P.; Slaughter, Brian D.; Rohner, Nicolas
Abstract
Reduced parasitic infection rates in the developed world are suspected to underlie the rising prevalence of autoimmune disorders. However, the long-term evolutionary consequences of decreased parasite exposure on an immune system are not well understood. We used the Mexican tetraAstyanax mexicanusto understand how loss of parasite diversity influences the evolutionary trajectory of the vertebrate immune system, by comparing river with cave morphotypes. Here, we present field data affirming a strong reduction in parasite diversity in the cave ecosystem, and show that cavefish immune cells display a more sensitive pro-inflammatory response towards bacterial endotoxins. Surprisingly, other innate cellular immune responses, such as phagocytosis, are drastically decreased in cavefish. Using two independent single-cell approaches, we identified a shift in the overall immune cell composition in cavefish as the underlying cellular mechanism, indicating strong differences in the immune investment strategy. While surface fish invest evenly into the innate and adaptive immune systems, cavefish shifted immune investment to the adaptive immune system, and here, mainly towards specific T-cell populations that promote homeostasis. Additionally, inflammatory responses and immunopathological phenotypes in visceral adipose tissue are drastically reduced in cavefish. Our data indicate that long-term adaptation to low parasite diversity coincides with a more sensitive immune system in cavefish, which is accompanied by a reduction in the immune cells that play a role in mediating the pro-inflammatory response. Comparing Mexican cavefish from rivers with those from caves, the authors show increased sensitivity of the innate and adaptive immune system that is accompanied by a reduced investment in the innate immune system as an evolutionary response to lower parasite diversity.
Klotho downregulation contributes to myocardial damage of cardiorenal syndrome in sepsis
MOLECULAR MEDICINE REPORTS
Authors: Yan, Fei; Feng, Yue; Chen, Jin; Yan, Jing
Abstract
Klotho is a type of single-pass transmembrane protein that is important for the proper function of numerous organs. The aim of the present study was to investigate the role of Klotho in sepsis-associated myocardial damage. In the present study, reverse transcription-quantitative PCR, western blotting and ELISA were conducted to examine the expression levels of function genes, and flow cytometry was performed to detect cell apoptosis and reactive oxygen species. The present study demonstrated that Klotho expression was significantly downregulated in septic mice and that the myocardial function of septic mice improved after treatment with exogenous Klotho protein. It further demonstrated that indoxyl sulfate inhibited the expression of Klotho protein. In addition, decreased Klotho protein further led to activation of the reactive oxygen species-p38 mitogen-activated protein kinase signaling pathway, finally resulting in myocardial damage. In conclusion, Klotho protein may be a key regulator in the myocardial damage of cardiorenal syndrome in sepsis. It also has a potential to be a therapeutic target for sepsis-associated myocardial damage in the future.