Functional characterization of flavonoid 3 '-hydroxylase, CsF3 ' H, from Crocus sativus L: Insights into substrate specificity and role in abiotic stress
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS
Authors: Baba, Shoib Ahmad; Ashraf, Nasheeman
Abstract
Stress-responsive dihydroxy flavonoids exhibit capability to inhibit the accretion of reactive oxygen species (ROS). The formation of these dihydroxy flavonols is catalyzed by flavonoid hydroxylases which are among the rate limiting enzymes of flavonoid biosynthesis pathway. Although flavonoid hydroxylases have been identified in several plant species but their role in abiotic stress is not explicitly documented. In the present study we report identification of all the flavonoid biosynthesis pathway genes of Crocus sativus and their expression profiling. We also report functional characterization of flavonoid 3' hydroxylase (CsF3'H) and attempt to explore its physiological role in vitro and in planta. The results indicated that CsF3'H is 1608 bp long encoding 535 amino acids. Docking and enzyme kinetic studies revealed that CsF3'H catalyzes hydroxylation of naringenin and dihydrokaempferol to eriodictoyl and dihydroquercetin respectively, but exhibits higher affinity for naringenin. Further, CsF3'H showed comparatively higher expression in floral tissues particularly stigma and its expression was significantly enhanced in response to UV-B, dehydration and salinity stress indicative of its role in stress. The expression of CsF3'H was associated with concomitant accumulation of eriodictoyl and dihydroquercetin. Transient overexpression of CsF3'H in Nicotiana benthamiana leads to the accumulation of substantial amounts of eriodictoyl and dihydroquercetin. Further, it was observed that transient expression of CsF3'H conferred tolerance to UV-B and dehydration stress as was evident from higher chlorophyll and soluble sugar and lower MDA contents. Taken together, these results suggest that CsF3'H confers tolerance to UV-B and dehydration in planta through synthesis of dihydroflavonols.
Endometrial stromal cell inflammatory phenotype during severe ovarian endometriosis as a cause of endometriosis-associated infertility
REPRODUCTIVE BIOMEDICINE ONLINE
Authors: Anupa, Geethadevi; Poorasamy, Jeevitha; Bhat, Muzaffer A.; Sharma, Jai Bhagwan; Sengupta, Jayasree; Ghosh, Debabrata
Abstract
Research question: Do endometrial stromal cells from primary infertile patients with severe ovarian endometriosis display differential secretory profiles of inflammation-associated cytokines during the implantation window that may cause infertility? Design: Forty-eight cytokines were measured in conditioned medium of isolated endometrial stromal cells obtained from primary infertile patients without endometriosis (control group, n = 12) or with stage IV ovarian endometriosis (ovarian endometriosis group, n = 14) using multiplex assays. Key cytokines showing differential secretory profiles were validated using Western immunoblotting. Cellular phenotypic validation was carried out in vitro by comparing proliferation and migration capacity between control (n = 6) and ovarian endometriosis (n = 7) groups. Results: CCL3, CCL4, CCL5, CXCL10, FGF2, IFNG, IL1RN, IL5, TNFA, and VEGF could be detected only in the conditioned media of stromal cells obtained from the ovarian endometriosis group. Among other cytokines detected in the conditioned media of both groups, CCL2 (P = 0.0018), CSF3 (P = 0.0017), IL1B (P = 0.0066), IL4 (P = 0.036), IL6 (P = 0.0039) and IL13 (P = 0.036) were found to be higher, whereas the concentration of IL18 was lower (P = 0.023) in the ovarian endometriosis group. Concentrations of CCL2, IL1B, IL4 and IL13 in conditioned medium reflected significant diagnostic performance for predicting ovarian endometriosis. Cellular phenotypic validation in vitro revealed an enhanced proliferative phenotype (P = 0.046) with no change in cell migratory capacity of endometrial stromal cells from the ovarian endometriosis group. Conclusions: Endometrial stromal cells derived from severe ovarian endometriosis samples displayed a hyperinflammatory and hyperproliferative bias in the endometrial stroma during the 'window of implantation' putatively causing loss of fecundability.