Expression And Transcriptome Analysis Of Aquaporins In The Kidney Of Saiga Tatarica

?Purpose?The large-scale decrease in the number of Saiga tatarica in recent years has made people more aware of the importance of protecting Saiga tatarica,and more basic research is urgently needed to understand the important role of Saiga tatarica in its ecological niche.Saiga tatarica is suitable for living in arid and semi-arid deserts.Survival under extreme conditions requires its body to maintain strong water stability.Kidney aquaporins participate in water transport and concentrate urine.Among them,AQP2,AQP4 and AQP8 play an important role in promoting electrolyte balance,acid-base balance and water-salt balance,and are important components of cells.Using the goat as a control,the expression of aquaporins were studied in the kidney of Saiga tatarica of different ages.Combined with the morphological structure index of the kidney,it is helpful to understand the characteristics and changes of aquaporins in the body,and try to preliminary explain the reasons for its adaptation to arid and semi-arid environments during its growth and the regulation mechanism of water balance in the body.Transcriptome in-depth explores the differentially expressed genes that are significantly enriched during the growth of Saiga tatarica,and screens the changes in differentially expressed genes in signal pathways related to aquaporins,and in-depth analysis of their adaptive mechanisms in arid and semi-arid environments.?Methods?Histological observation of glomerulus,statistics and comparison of related structural indexes of Saiga tatarica glomerulus.Immunohistochemistry was used to detect the expression position of AQP2,AQP4 and AQP8 in kidney of Saiga tatarica and quantitative statistical analysis.Western blotting was used to detect the protein level of AQP2,AQP4 and AQP8 in kidney of Saiga tatarica.q RT-PCR was used to detect the transcript level of AQP2,AQP4 and AQP8 in kidney of Saiga tatarica.Transcriptome sequencing analyzed the functional enrichment and signal pathway enrichment of Saiga tatarica differentially expressed genes in kidney,and screened the differentially expressed genes related to AQP2,AQP4 and AQP8.?Results?The glomerular volumes of Saiga tatarica and goat from young to adult were(1.60±0.12)×10~6?m~3,(4.13±0.15)×10~6?m~3,(1.31±0.06)×10~6?m~3,and(2.36±0.10)×10~6?m~3 respectively.The glomerular volume of adult Saiga tatarica was significantly higher than that of its young(P<0.001)and adult goat(P<0.001).Further investigate the relationship between the glomerular volume and the Bowman's capsule volume,and found that the glomerular volume of the Saiga tatarica had a high correlation with the Bowman's capsule volume.The correlation between the adult Saiga tatarica(r=0.9688,P<0.0001)higher than in young(r=0.9525,P<0.0001).The AQP2,AQP4 and AQP8 of Saiga tatarica and goat kidneys were all located in the cortical renal tubules and medullary collecting ducts.Combined with the results of western blotting,the expression of AQP2 in adult Saiga tatarica was significantly higher than that of its young(P<0.001)and adult goat(P<0.001).The expression of AQP4 in adult Saiga tatarica was significantly higher than that of its young(P<0.05),and there was no significant difference between goat of the same age.The expression of AQP8 in adult Saiga tatarica was significantly higher than that of its young(P<0.05),and there was no significant difference between goat of the same age.q RT-PCR detected AQP2,AQP4 and AQP8 transcription expression,the results were consistent with the results of protein.The transcriptional expression of three aquaporins in adult Saiga tatarica were significantly higher than those in their youth(P<0.01).Transcriptome sequencing of the Saiga tatarica kidney showed that there were10,122 differentially expressed genes in Saiga tatarica,5,507 of which were up-regulated and 4,615 were down-regulated.Goat had 1,530 differentially expressed genes,of which 1,019 were up-regulated and 511 were down-regulated.The functional enrichment and signal pathway enrichment of the differentially expressed genes were different.The differential expression genes related to AQP2,AQP4 and AQP8 were screened,and 17,51 and 34 genes were found in the Saiga tatarica respectively,and 3,20 and 17 genes in the goat respectively.The number of differentially expressed genes in Saiga tatarica was higher than that in goat.?Conclusion?The size of the glomerulus of Saiga tatarica gradually increases during development,and the size is larger than that of goat of the same age.There is a high correlation between the volume of glomerulus and the volume of Bowman's capsule,and there may be an optimal ratio to achieve high efficiency filtration rate.During the growth and development of Saiga tatarica,AQP2,AQP4 and AQP8are expressed in the cortical renal tubules and medullary collecting duct.The protein expression of AQP2,AQP4 and AQP8 coincide with the expression of transcription.They are all up-regulated,which helps to increase the water reabsorption of the renal tubules and provides the structural and molecular basis for its adaptation to arid and semi-arid environment.There are differentially expressed genes during the development of Saiga tatarica,and the number of differentially expressed genes in signal pathways related to AQP2,AQP4 and AQP8 is more than that of goat.To a certain extent,the drought-tolerant adaptation of Saiga tatarica can jointly regulate the protein expression and transcription level through aquaporin-related signaling pathways,and improve its drought-tolerant molecular mechanism.