Sprr2f protects against renal injury by decreasing the level of reactive oxygen species in female mice
Renal injury leads to chronic kidney disease for which women are not only more likely to be diagnosed with than men but also have poorer outcomes as well. We have previously shown that expression of Sprr2f, a member of the Small Proline Rich Region (Sprr) gene family, is increased several hundred fold after renal injury using a unilateral ureter obstruction (UUO) mouse model. To better understand the role of Sprr2f in renal injury, we generated a Sprr2f knockout (Sprr2f-KO) mouse model using CRISPR-Cas9 technology. To identify genes that are differentially expressed in Sprrf2f-KO mice after UUO, we performed gene expression profiling by RNA-seq on kidney tissues harvested from Sprr2f-KO mice at time 0 (n=4) and after 5 days (n=3), a time known to show dramatic changes in gene expression. Compared to day 0, expression levels of 162 genes were significantly changes with 121 up-regulated and 41 down-regulated 5 days after obstruction. Enrichment analysis using PANTHER Classification System  identified 12 and 2 pathways enriched in genes that are upregulated or downregulated after UUO respectively. Eleven out of the 12 pathways enriched in the genes upregulated after UUO are related to metabolism such as drug metabolic process, consistent with a profound role of kidney as a major clearance organ of the body responsible for the elimination of many xenobiotics and prescription drugs. Interestingly, the only pathway not related to metabolism enriched in genes upregulated by UUO is oxidation-reduction, suggesting a potential role of oxidative stress in renal damage after UUO in Sprr2-KO animals. This phenotype is not observed in Sprr2f-WT animals after UUO in our previous gene expression profiling study, suggesting that Sprr2f function is sufficient to protect kidney from oxidative damage after UUO in Sprr2f-WT animals. Overall design: To identify genes that are differentially expressed in Sprrf2f-KO mice after UUO, we performed gene expression profiling by RNA-seq on kidney tissues harvested from Sprr2f-KO mice at time 0 (n=4) and after 5 days (n=3), a time known to show dramatic changes in gene expression. Total RNA was isolated from fresh frozen kidney tissues and delivered to Novogene for next generation sequencing using Illumina Hiseq system. Raw data were analyzed in house using STAR and HTSeq.