Buffalo liver transcriptome analysis suggests immune tolerance as its key adaptive mechanism during early postpartum negative energy balance

Expression and Immunolocalization of Aquaporins in the Buffalo Liver and Adipose Tissue

Increasing incidences of fatty liver in humans and animals worldwide is the leading cause of liver related morbidities. Currently, in the face of the growing global increase in fatty liver, and the necessity to explore new factors significantly affecting it, aquaporins (AQPs) have become the focus of interest for many researchers. AQPs are membrane integral proteins involved in the transport of water, glycerol and other small solutes. These are expressed in all tissues and play multiple roles under normal and pathophysiological conditions. Despite ongoing advancements in understanding the involvement of aquaporins in metabolic processes, there remains a notable lack of knowledge concerning cellular and subcellular localization of the AQPs in bovine tissues and organs. Understanding this could provide a new therapeutic target for metabolic syndromes such as fatty liver disease in bovine. In this study, AQPs in bovine liver, adipose tissue and gall bladder are examined using immunohistochemistry. AQP9 immunoreactivity is predominantly detected at the sinusoidal surfaces of hepatocytes. AQP8 is mostly intracellular and localized to the central vein and sinusoid, whereas AQP7 is found around the portal vein. Notably, AQP3 is observed in the bovine gall bladder and adipose tissue but not in the liver. In adipose tissue, AQP7 is also detected in the cytoplasmic membranes of adipocytes. AQPs in liver and adipose tissue were also studied using the western blotting technique. Higher AQP9 and AQP3 expression is observed in the liver and adipose tissue, respectively, indicating they are the dominant aquaporins in these tissues. This suggests they could be potential therapeutic targets for treating fatty liver disease and other metabolic disorders in bovine.

Comparative assessment of growth performance of indigenous and cross-bred calves subjected to combined stressors (heat and nutritional)

This study evaluated the impact of combined stressors (heat and nutritional stresses) on the growth and adaptive capability of Sahiwal (SW) and Karan Fries (KF) calves during the summer season. Calves in each breed were randomly divided into four groups. In SW breed the groupings were as follows: SWC (n = 4; Sahiwal Control); SWHS (n = 4; Sahiwal Heat Stress); SWNS (n = 4; Sahiwal Nutritional Stress) and SWCS (n = 4; Sahiwal Combined Stresses). Likewise, in the KF breed, KFC (n = 4; Karan Fries Control); KFHS (n = 4; Karan Fries Heat Stress); KFNS (n = 4; Karan Fries Nutritional Stress), and KFCS (n = 4; Karan Fries Combined Stresses). Control (C) and Heat Stress (HS) calves were fed ad libitum while Nutritional Stress (NS) and Combined Stresses (CS) calves were fed restricted feed (50% of C calves of respective breed) to induce nutritional stress in both the breeds. SWHS, SWCS, KFHS, and KFCS were exposed to summer heat stress from 1000 to 1600 h. All growth and adaptation variables were recorded at fortnightly intervals. Respiration rate, pulse rate, and rectal temperature during the afternoon were significantly (P < 0.01) higher in the CS group in both breeds. Further, CS had significantly (P < 0.05) higher plasma growth hormone and cortisol levels. Insulin-like growth factor-1, Triiodothyronine, and Thyroxine levels significantly decreased (P < 0.05) in the CS group in both breeds. Interestingly, heat stress didn't affect SWHS and KFHS bodyweight, however, a significant (P < 0.05) decrease in body weight of SWCS and KFCS was observed when compared with C. Hepatic mRNA expression of growth hormone, insulin-like growth factor-1, and growth hormone receptor significantly (P < 0.05) varied when compared between C and CS groups in both the breeds. The overall magnitude of stress was more pronounced in KF compared to the SW breed. This study concludes that when two stressors occur concurrently, they may have a greater influence on the adaptive capability of calves. Further, SW had better tolerance levels than KF, confirming the indigenous breed's superiority over cross-bred.

MiRNA-Seq reveals key MicroRNAs involved in fat metabolism of sheep liver

There is a genetic difference between Hu sheep (short/fat-tailed sheep) and Tibetan sheep (short/thin-tailed sheep) in tail type, because of fat metabolism. Previous studies have mainly focused directly on sheep tail fat, which is not the main organ of fat metabolism. The function of miRNAs in sheep liver fat metabolism has not been thoroughly elucidated. In this study, miRNA-Seq was used to identify miRNAs in the liver tissue of three Hu sheep (short/fat-tailed sheep) and three Tibetan sheep (short/thin-tailed sheep) to characterize the differences in fat metabolism of sheep. In our study, Hu sheep was in a control group, we identified 11 differentially expressed miRNAs (DE miRNAs), including six up-regulated miRNAs and five down-regulated miRNAs. Miranda and RNAhybrid were used to predict the target genes of DE miRNAs, obtaining 3,404 target genes. A total of 115 and 67 GO terms as well as 54 and 5 KEGG pathways were significantly (padj &lt; 0.05) enriched for predicted 3,109 target genes of up-regulated and 295 target genes of down-regulated miRNAs, respectively. oar-miR-432 was one of the most up-regulated miRNAs between Hu sheep and Tibetan sheep. And SIRT1 is one of the potential target genes of oar-miR-432. Furthermore, functional validation using the dual-luciferase reporter assay indicated that the up-regulated miRNA; oar-miR-432 potentially targeted sirtuin 1 (SIRT1) expression. Then, the oar-miR-432 mimic transfected into preadipocytes resulted in inhibited expression of SIRT1. This is the first time reported that the expression of SIRT1 gene was regulated by oar-miR-432 in fat metabolism of sheep liver. These results could provide a meaningful theoretical basis for studying the fat metabolism of sheep.

De Novo Transcriptome Dataset Generation of the Swamp Buffalo Brain and Non-Brain Tissues

The sequenced data availability opened new horizons related to buffalo genetic control of economic traits and genomic diversity. The visceral organs (brain, liver, etc.) significantly involved in energy metabolism, docility, or social interactions. We performed swamp buffalo transcriptomic profiling of 24 different tissues (brain and non-brain) to identify novel transcripts and analyzed the differentially expressed genes (DEGs) of brain vs. non-brain tissues with their functional annotation. We obtained 178.57 Gb clean transcriptomic data with GC contents 52.77%, reference genome alignment 95.36%, exonic coverage 88.49%. Totally, 26363 mRNAs transcripts including 5574 novel genes were obtained. Further, 7194 transcripts were detected as DEGs by comparing brain vs. non-brain tissues group, of which 3,999 were upregulated and 3,195 downregulated. These DEGs were functionally associated with cellular metabolic activities, signal transduction, cytoprotection, and structural and binding activities. The related functional pathways included cancer pathway, PI3k-Akt signaling, axon guidance, JAK-STAT signaling, basic cellular metabolism, thermogenesis, and oxidative phosphorylation. Our study provides an in-depth understanding of swamp buffalo transcriptomic data including DEGs potentially involved in basic cellular activities and development that helped to maintain their working capacity and social interaction with humans, and also, helpful to disclose the genetic architecture of different phenotypic traits and their gene expression regulation.

Meprin A1 subunit beta gene polymorphism is associated with the length of post-partum anestrus interval in Murrah buffaloes

Postpartum anestrus interval (PPAI) is the interval between parturition and the first postpartum estrus exhibition in animals. Appearance of both normal and PPA buffaloes under the same farm conditions indicates the role of possible genetic predisposition to PPA. To identify the genetic and non-genetic factors associated with PPA in buffaloes, we collected data on PPAI and other 38 non-genetic variables from 575 Murrah buffaloes in the field conditions and identified the PPA associated non-genetic factors in our previous study. To explore the genetic factors associated with the unexplained variation in PPAI residuals, the present study identified 41 single nucleotide polymorphisms (SNPs) in 13 candidate genes using Sanger sequencing. Exploration of their association with the PPAI residuals of 50 extreme PPA and 50 normal buffaloes identified the significant (P < 0.01) association of the SNP (g.37219977A>G) in the 3'-UTR region of the Meprin A 1 subunit beta (Mep1b) gene with PPAI, which was further validated (P = 0.058) in a large population sample (n = 417). Bioinformatics analysis of the 3'-UTR region has identified three miRNA, bta-miR-2420, bta-miR-2325b and bta-miR-453 that could regulate Igf-1 in the plasma of animals with different genotypes (GG, AG and AA). The higher Igf-1 levels in the GG genotypes than that of AA and AG genotypes of this SNP (g.37219977A>G) further suggest the association of Mep1b gene with PPA condition in Murrah buffaloes. As a result of this study, we propose that buffaloes with protective alleles at this SNP be selected to improve the herd's reproductive efficiency.

Salivary TIMP1 and predicted mir-141, possible transcript biomarkers for estrus in the buffalo (Bubalus bubalis)

Successful reproductive management of buffaloes depends primarily upon timely estrus identification. However, 50% of the estrus events are undetected in buffaloes with the available estrus identification methods, leading to huge financial loss to buffalo farmers. Hence, there is an urgent need to develop an alternative and accurate estrus identification method, particularly on the basis of biomarkers in non-invasive fluids. Thus, the present study aimed to identify RNA based estrus biomarkers in cell free saliva in Bubalus bubalis, so that they can be used for future field applicable RT-LAMP colour reactions. RNA-Seq analysis of cell free salivary RNA showed 49 differentially abundant mRNAs between the estrus and diestrus stages. Among five mature miRNAs predicted from the RNA-Seq data, four were found differentially altered at the estrus stage than the diestrus stage. Validation study by direct salivary transcript analysis (DSTA) on 6 selected mRNAs (PPARGC1a, TIMP1, PEBP4, CSPG5, PRHR and ATOH7) and 5 miRNAs (bta-miR-92b, bta-miR-302d, bta-miR-141, bta-miR-27a and bta-let-7a-5p) showed significantly higher levels of TIMP1 (3.46 fold; P < 0.5) and bta-mir-141 (1.33 fold; P < 0.5) in cell-free saliva at the estrus stage compared to the diestrus stage. Hence, TIMP1 and miR-141 appear to be the possible transcript biomarkers for estrus in the cell free saliva of the buffalo. However, further validation studies are required in a large population of buffaloes to determine their estrus biomarker potential before considering them for RT-LAMP colour reaction.

Association of taurine with ovarian follicular steroids and postpartum anestrus condition in Murrah buffaloes

Taurine is an abundant intracellular beta-amino acid majorly synthesized in the liver and transported through plasma. In mammals, taurine was reported to be involved in various physiological functions, including the enhancement of testosterone levels, the major estradiol precursor. Therefore, we hypothesize that taurine levels are associated with ovarian follicular steroids as well as with a reproductive problem called postpartum anestrus (PPA) in dairy buffaloes. To understand the taurine levels and its possible role in buffalo ovarian follicles, a correlation was established among taurine, estradiol, and testosterone levels in the ovarian follicular fluid. For this purpose, buffalo ovaries were obtained from the slaughterhouse, and follicular fluid samples were collected from small (<4 mm), medium (4-8 mm) and large (>8 mm) follicles. Taurine and steroid levels in the follicular fluid were analyzed by TLC and ELISA, respectively. Taurine and testosterone levels were significantly (P < 0.05) higher in the follicular fluid of small and medium follicles than large follicles, whereas the estradiol levels were significantly (P < 0.001) higher in the large follicles. Thus, taurine showed a positive correlation (r = 0.75) with testosterone and a negative correlation (r = -0.77) with estradiol in buffalo follicular fluid, indicating its possible role in testosterone function during follicular development. Interestingly, significantly (P < 0.001) lower plasma taurine levels in PPA (n = 50) than normal cyclic (n = 50) buffaloes represented its association with PPA. Therefore, our present study recommends the need for future nutrition studies on taurine supplementation to PPA buffaloes.

Apolipoprotein A1 and Ceruloplasmin, the key crosstalk players between the liver and adipose tissue during early postpartum of buffaloes: An in-Silico transcriptome based network analysis

Physiological transition from pregnancy to lactation during early postpartum creates a high-energy demand in females towards milk production for the survival of new offspring. Ruminant milk contains high amount of lactose, a disaccharide of the glucose and galactose. The milk yield of the animals is also dependent on the lactose amount. In ruminants, glucose is majorly supplied by the liver, which obtains energy from the adipose tissue during energy demands. Therefore, there should be an intricate crosstalk between these two tissues for efficient maintenance of energy for normal physiological needs and milk production. In the present study, we analyzed the transcriptome data previously obtained from the buffalo liver and adipose tissue on the 15th day and 30th day of lactation by using several bioinformatics tools such as PANTHER, Secretome-P, STRING and CPDB. Our analysis identified a total of 24 signaling molecules as interactive players between the liver and adipose tissue during early postpartum of buffaloes. Particularly, the liver appears to interact with the adipose tissue and itself majorly through an endocrine/autocrine molecule, APOA1. Similarly, the adipose tissue appears to interact with the liver and itself majorly through an endocrine/autocrine molecule, CP (ceruloplasmin). The APOA1 and CP may counteract with each other on lipolysis in buffalo adipose tissue because of their common signaling molecules being shared. In addition, the interaction between the adipose derived ceruloplasmin and the liver derived lactoferrin seems to be important during early postpartum of buffaloes. The importance of this interaction needs to be studied in further studies.