[Transcriptome analysis of venom gland and identification of functional genes for snake venom protein in Agkistrodon acutus]

Agkistrodon acutus is a traditional Chinese herb medicine which has immunological regulation,anti-tumor,anti-inflammatory and analgesic effects,which is mainly used for the treatment of rheumatoid arthritis,ankylosing spondylitis,sjogren's syndrome and tumors. In order to excavate more important functional genes from A. acutus,the transcriptome of the venom gland was sequenced by the Illumina Hi Seq 4000,and 32 862 unigenes were assembled. Among them,26 589 unigenes were mapped to least one public database. 2 695 unigenes were annotated and assigned to 62 TF families,and 5 920 SSR loci were identified. The majority of mapped unigenes was from Protobothrops mucrosquamatus in the NR database,which revealed their closest homology. Three secretory phospholipase A_2 with different amino acid sequences showed similar spatial structures and all had well-conserved active sites. The 3 D structural models of C-type lectin showed conserved glycosylation binding sites( Asn45). This study will lay the foundation for the further study of the function of snake venom protein,and promoting the development and utilization of genome resources from A. acutus.

Agkistrodon ameliorates pain response and prevents cartilage degradation in monosodium iodoacetate-induced osteoarthritic rats by inhibiting chondrocyte hypertrophy and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Osteoarthritis (OA), characterized by joint pain and cartilage degradation, is the most common form of joint disease worldwide but with no satisfactory therapy available. The ethanol extract of Agkistrodon acutus (EAA) has been widely used as a traditional Chinese medicine (TCM) for the treatment of arthralgia and inflammatory diseases, but there is no report regarding its efficacy on OA to date. Here, we determined the effects of EAA on the pain behavior and cartilage degradation in vivo and clarified its target genes and proteins associated with chondrocyte hypertrophy and apoptosis in vitro.

MATERIALS AND METHODS

In vivo OA model was established by intra-articular injection (1.5 mg) of monosodium iodoacetate (MIA) into rats and weekly treated by intra-articular administration of EAA at a dose range from 0.3 to 0.9 g/kg for four weeks. The pain behavior parameters, thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) were tested before and after the treatment. Then histopathologic, immunohistochemical and TUNEL analyses of the articular cartilage were conducted, followed by Mankin's scoring. In vitro, the effects of EAA on chondrocytes were evaluated via assays of cell viability, immunofluorescence, real time PCR, and Western blot. UPLC-MS was applied to determine the chemical composition of EAA.

RESULTS

The animal data showed that EEA not only attenuated the pain hypersensitivity but also blocked the cartilage degeneration by improving chondrocyte survival and suppressing chondrocyte apoptosis at a dose-dependent manner in OA rats. Furthermore, EAA remarkably restored the abnormal expression of collagen type II (Col2) and matrix metalloproteinase-13 (MMP13) in cartilage of OA rats. The cellular data showed that EAA significantly increased the cell viability of chondrocytes against OA-like damage and restored the abnormal expressions of Col2 and MMP13 in damaged chondrocytes. The molecular data showed that EAA significantly restored the abnormal mRNA expressions of Col2, Col10, MMP2 and MMP13 as well as the abnormal protein expressions of MMP13, PARP (total and cleaved) in chondrocytes under pathological condition. UPLC-MS analysis showed the known main components of EAA, including amino acides (glycine, L-aspartic acid, L-glutamic acid, and L-hydroxyproline), nucleoside (uridine), purines (xanthine and hypoxanthine), and pyrimidine (uracil).

CONCLUSIONS

Our data demonstrate that EAA exerts antinociceptive and chondroprotective effects on OA through suppressing chondrocyte hypertrophy and apoptosis with restoration of the molecular expressions of anabolism and catabolism in chondrocytes. It provides a promising TCM candidate of novel agent for OA therapy.

Isolation and biochemical characterization of a gamma-type phospholipase A2 inhibitor from Macropisthodon rudis snake serum

A novel phospholipaseA₂ (PLA₂) inhibitory protein (PLI) was purified from the serum of Macropisthodon rudis, a non-venomous snake mainly found in southern China. The molecular mass of the purified PLI was 160 kDa as determined by Superdex 200HR; however, the PLI protein had only one subunit of 25.4 kDa as determined by 12% SDS-PAGE, indicating an oligomeric protein. PLI cDNA obtained by PCR from the liver of Macropisthodon rudis, revealed 549 bps coding for a mature protein of 183 amino acid residues. Based on an amino acid sequence alignment with venomous and non-venomous snakes, this inhibitor was determined to be in the γ type family of PLI. In vitro experiments showed that PLIγ inhibited enzymatic, inflammatory, and antibacterial activities of snake venom PLA₂ isolated from Agkistrodon acutus.