Cloning, sequencing and expression of cDNA of bovine neutrophil beta-defensin from water buffalo (Bubalus bubalis)

Differential expression of endometrial toll-like receptors (TLRs) and antimicrobial peptides (AMPs) in the buffalo (Bubalus bubalis) with endometritis

Toll like receptors (TLRs) and β-defensins expressed in the endometrium are part of the innate uterine defense mechanism (UDM). In the present study, transcriptional profile of TLRs (1-3, 6-8, 10, and) and β-defensins such as lingual antimicrobial peptide (LAP), tracheal antimicrobial peptide (TAP) and bovine neutrophil beta-defensin 4 (BNBD4) were studied. Bubaline genitalia were collected from abattoir and the endometrium was categorized into one of the following seven groups (n = 7/group) based on cyclicity and endometritis: follicular non-endometritis (FNE), luteal non-endometritis (LNE), follicular cytological endometritis (FCE), luteal cytological endometritis (LCE), follicular purulent endometritis (FPE), luteal purulent endometritis (LPE) and acyclic non-endometritis (ANE). Cytological endometritis (CE) was diagnosed by uterine cytology while purulent endometritis (PE) was diagnosed by the presence of purulent or mucopurulent exudate in the uterine lumen. Real time PCR was performed and the relative fold change was analysed. TLR1 and BNBD4 transcripts were not found in the buffalo endometrium. Of all the innate immune genes studied, upregulation of TLR and β-defensins was mostly contributed by the inflammatory status of endometrium. Further, there was a prominent upregulation of TAP in buffaloes with endometritis. However, no association could be found between the inflammatory status of the endometrium and phase of estrous cycle with respect to the expression of TLRs and β-defensins.

Antimicrobial peptides of buffalo and their role in host defenses

Antimicrobial peptides (AMPs) are highly conserved components of the innate immune system found among all classes of life. Buffalo (Bubalus bubalis), an important livestock for milk and meat production, is known to have a better resistance to many diseases as compared to cattle. They are found to express many AMPs such as defensins, cathelicidins, and hepcidin which play an important role in neutralizing the invading pathogens. Buffalo AMPs exhibit broad-spectrum antimicrobial activity against both Gram-positive and Gram-negative bacteria. Similar to its natural form, synthetic analogs of buffalo AMPs are also antimicrobial against bacteria and even fungus making them a good target for the development of therapeutic antimicrobials. In addition to its antimicrobial effect, AMPs have been demonstrated to have a number of immunomodulatory functions, and their genes are responsive to infections. Further, induction of their gene expression by external factors may help in preventing infectious diseases. This review briefly discusses the AMPs of buffalo identified to date and their possible role in innate immunity.

Exploring genetic polymorphism in innate immune genes in Indian cattle (Bos indicus) and buffalo (Bubalus bubalis) using next generation sequencing technology

Activation of innate immunity initiates various cascades of reactions that largely contribute to defense against physical, microbial or chemical damage, prompt for damage repair and removal of causative organisms as well as restoration of tissue homeostasis. Genetic polymorphism in innate immune genes plays prominent role in disease resistance capabilities in various breeds of cattle and buffalo. Here we studied single nucleotide variations (SNP/SNV) and haplotype structure in innate immune genes viz CHGA, CHGB, CHGC, NRAMP1, NRAMP2, DEFB1, BNBD4, BNBD5, TAP and LAP in Gir cattle and Murrah buffalo. Targeted sequencing of exonic regions of these genes was performed by Ion Torrent PGM sequencing platform. The sequence reads obtained corresponding to coding regions of these genes were mapped to reference genome of cattle BosTau7 by BWA program using genome analysis tool kit (GATK). Further variant analysis by Unified Genotyper revealed 54 and 224 SNPs in Gir and Murrah respectively and also 32 SNVs was identified. Among these SNPs 43, 36, 11,32,81,21 and 22 variations were in CHGA, CHGB, CHGC, NRAMP1, NRAMP2, DEFB1 and TAP genes respectively. Among these identified 278 SNPs, 24 were found to be reported in the dbSNP database. Variant analysis was followed by structure formation of haplotypes based on multiple SNPs using SAS software revealed a large number of haplotypes. The SNP discovery in innate immune genes in cattle and buffalo breeds of India would advance our understanding of role of these genes in determining the disease resistance/susceptibility in Indian breeds. The identified SNPs and haplotype data would also provide a wealth of sequence information for conservation studies, selective breeding and designing future strategies for identifying disease associations involving samples from distinct populations.

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Sequencing of exonic regions of 10 selected innate immune genes, 895.60 Mb data was generated.

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Variant analysis using GATK pipeline revealed 278 SNPs, 32 SNVs and from these 24 were found to be reported.

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43, 36 and 11 SNPs were observed in chromagranin genes viz. CHGA, CHGB and CHGC respectively.

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32 and 81 SNPs were identified in NRAMP genes viz. NRAMP1 and NRAMP2 respectively.

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21 and 22 SNPs were observed in β-defensin genes viz. DEFB1 and TAP respectively.

Molecular analysis and recombinant expression of bovine neutrophil β-defensin 12 and its antimicrobial activity

To analyze molecular characteristics and antimicrobial activity of bovine neutrophil β-defensin 12 (BNBD12), Pro-BNBD12 gene was amplified from Chinese Holstein cow using reverse transcription polymerase chain reaction. Based on the sequence of mature BNBD12 and codon preference in E. coli, a modified mature BNBD12 cDNA was synthesized, cloned into pET32a (+) vector and expressed in E. coli BL21 as a 26 kD fusion protein after isopropyl β-D-1-thiogalactopyranoside induction. The expressed mature BNBD12 accounted for 21.4% of total protein. 0.05 mg/ml purified BNBD12 had antimicrobial activity against both E. coli and S. aureus in vitro assayed by agar diffusion method. Electron microscopy found that BNBD12 treatment of E. coli and S. aureus could induce cell content leakage. Taking together, BNBD12 protein was successfully expressed in E. coli and it has antimicrobial activity against both Gram-positive and negative bacteria and potentials in control of mastitis clinically.