Role of Penaeus monodon hemocyte homeostasis associated protein (PmHHAP) in regulation of caspase-mediated apoptosis

Abstract

The viral responsive protein, PmHHAP, plays an important role in the control of hemocyte homeostasis in shrimps during viral infection. In this study, we further investigate the role of PmHHAP in the regulation of hemocyte apoptosis. RNA interference (RNAi) mediated gene silencing was used to suppress the PmHHAP expression and the change in hemocyte apoptosis was determined in the knockdown shrimp. Within circulating hemocytes, PmHHAP knockdown increased the number of annexin V-positive apoptotic cells and the combined caspase-3/-7 activity and induced the characteristic apoptotic DNA ladder. Furthermore, PmHHAP down-regulation was accompanied by significantly altered expression of apoptosis-related proteins including the effector caspases, PmCaspase and PmCasp. Yeast two-hybrid and co-immunoprecipitation assays showed that PmHHAP binds to the p20 domain of PmCasp. Moreover, the recombinant PmHHAP protein was able to reduce the caspase activity in the actinomycin D-treated hemocyte cells and rPmCasp-treated hemocyte cells. Taken together, our data indicate that PmHHAP regulates hemocyte homeostasis by inhibits apoptotic cell death through caspase activation.

Crustacean hematopoiesis

“…Knockdown experiments in shrimp have shown an increase in apoptosis followed by a decrease in the hyaline hemocyte number. The P. monodon HHAP was recently shown to bind to the p20 domain of a shrimp caspase, further confirming a role for HHAP in regulating apoptosis (Apitanyasai et al, 2015). Intriguingly, L. vannamei HHAP was shown to bind to Lamr in a manner similar to the CHF-like protein, indicating the involvement of this receptor in hemocyte homeostasis .…”

“…vannamei (Apitanyasai et al, 2015;Prapavorarat et al, 2010). The sequence of HHAP is not similar to that of CHF-like sequences; instead, these proteins contain a zinc finger CCHC domain.…”

MicroRNA and mRNA interactions coordinate the immune response in non-lethal heat stressed Litopenaeus vannamei against AHPND-causing Vibrio parahaemolyticus

“…As previously demonstrated, several miRNAs can target the same genes. Interestingly, several up-regulated miRNAs such as lva-miR-61, lva-bantam, lva-miR-70, lva-miR-6813-5p, lva-miR-7278-5p, lva-miR-279b-3p, and lva-miR-745b were predicted to target caspase, which is a protease enzyme that plays essential roles in programmed cell death for most crustacean species [22][23][24] . The down-regulation of caspase at 6 hpi, regulated by miR-NAs upon NLHS and VP AHPND infection, suggests that a lower number hemocyte might undergo apoptosis.…”

“…In hemocyte homeostasis, caspase and transglutaminase (TGase) are two important proteins for most crustacean species 22,23 . TGase transcript expression in NLHS-treated shrimp was up-regulated at 24 hpi upon VP AHPND challenge.…”

A potential application of shrimp antilipopolysaccharide factor in disease control in aquaculture

“…Haemocyte homoeostasis‐associated protein is a viral responsive gene that plays an important role in haemocyte homoeostasis (Prapavorarat, Vatanavicharn, Söderhäll & Tassanakajon ). In response to WSSV challenge, HHAP is a late viral responsive gene and its function appears to have a role in suppressing haemocyte apoptosis (Apitanyasai, Amparyup, Charoensapsri, Senapin & Tassanakajon ). At the early stage of viral infection, shrimp use apoptosis to eliminate the viral‐infected haemocytes and so reduce the production of new virions and restrict the spread of the infection, whereas at the late stage of infection, the virus uses the host machinery to expend and dissipate the newly formed viral particles by induction of apoptosis (Leu, Lin, Huang, Chen & Lo ).…”