Decreased tissue COX5B expression and mitochondrial dysfunction during sepsis-induced kidney injury in rats

Abstract

Background. Sepsis is defined as a life-threatening organ dysfunction due to a dysregulated host response to infection. Sepsis is the dominant cause of acute kidney injury (AKI), accounting for nearly 50% of episodes of acute renal failure. Signaling cascades and pathways within the kidney are largely unknown and analysis of these molecular mechanisms may enhance knowledge on pathophysiology and possible therapeutic options. Material and Methods. 26 male Wistar rats were assigned to either a sham group (control, = 6) or sepsis group (= 20; cecal ligature and puncture model, 24 and 48 hours after CLP). Surviving rats (= 12) were decapitated at 24 hours (early phase; = 6) or 48 hours (late phase; = 6) after CLP and kidneys removed for proteomic analysis. 2D-DIGE and DeCyder 2D software (-test, < 0.01) were used for analysis of significantly regulated protein spots. MALDI-TOF in combination with peptide mass fingerprinting (PMF) as well as Western Blot analysis was used for protein identification. Bioinformatic network analyses (STRING, GeneMania, and PCViz) were used to describe protein-protein interactions. Results. 12 spots were identified with significantly altered proteins (< 0.01) in the three analyzed groups. Two spots could not be identified. Four different proteins were found significantly changed among the groups: major urinary protein (MUP5), cytochrome c oxidase subunit B (COX5b), myosin-6 (MYH6), and myosin-7 (MYH7). A significant correlation with the proteins was found for mitochondrial energy production and electron transport. Conclusions. COX5B could be a promising biomarker candidate since a significant association was found during experimental sepsis in the present study. For future research, COX5B should be evaluated as a biomarker in both human urine and serum to identify sepsis.

Bioinformatical Analysis of Organ-Related (Heart, Brain, Liver, and Kidney) and Serum Proteomic Data to Identify Protein Regulation Patterns and Potential Sepsis Biomarkers

“…Thus, we cannot be sure that the derived functions and pathways in fact correspond to these functions in the respective organs. However, the previous organ proteomics analyses of this sepsis model confirm that most of the functions are associated with energy metabolism, mitochondrial function, and lipid metabolism [ 8 – 12 ].…”

“…Collecting data from the 5 previous studies [ 8 – 12 ], 80 statistically significant altered proteins (a total of 113 total spots) from sepsis related organs and serum were identified.…”

“…In this study, proteomic data of various experiments all using the same experimental sepsis model (i.e., cecal ligation and puncture, CLP) were analysed using bioinformatical methods to identify protein regulation patterns altered by sepsis [ 8 – 12 ]. To the best of our knowledge, this is the first study which compares proteomic data from a broad set of organs during sepsis to associated protein regulation patterns and pathways in serum.…”

“…For example, the cluster analyses revealed which proteins and functions were regulated at different stages during the course of sepsis. Furthermore, one-third of statistically significantly regulated proteins can be found in the mitochondria, underlining the importance of alteration of mitochondrial functions and even mitochondrial damage in the host response to sepsis [ 12 , 23 – 25 ].…”

“…To identify possible protein regulation patterns and to evaluate the interaction between protein alteration in sepsis affected organs and blood, proteomics data from the heart, brain, liver, kidney, and serum from previous studies was analysed [ 8 – 12 ].…”