Podocalyxin promotes an impermeable epithelium and inhibits pro-implantation factors to negatively regulate endometrial receptivity

Published: 14 December 2021Embryo implantation is a key step in establishing pregnancy and a major limiting factor in IVF. Implantation requires a receptive endometrium but the mechanisms governing receptivity are not well understood. We have recently discovered that podocalyxin (PCX or PODXL) is a key negative regulator of human endometrial receptivity. PCX is expressed in all endometrial epithelial cells in the non-receptive endometrium but selectively down-regulated in the luminal epithelium at receptivity. We have further demonstrated that this down-regulation is essential for implantation because PCX inhibits embryo attachment and penetration. However, how PCX confers this role is unknown. In this study, through RNAseq analysis of Ishikawa cell line stably overexpressing PCX, we discovered that PCX suppresses expression of genes controlling cell adhesion and communication, but increases those governing epithelial barrier functions, especially the adherens and tight junctions. Moreover, PCX suppresses multiple factors such as LIF and signaling pathways including Wnt and calcium signaling that support receptivity but stimulates anti-implantation genes such as LEFTY2. Functional studies confirmed that PCX promotes epithelial barrier functions by increasing key epithelial junction proteins such as E-cadherin and claudin 4. PCX thus promotes an anti-adhesive and impermeable epithelium while impedes pro-implantation factors to negatively control endometrial receptivity for implantation.Sophea Heng, Nirukshi Samarajeewa,Yao Wang, SarahG. Paule, James Breen Guiying Ni

BIOLOGICAL AND CHEMICAL PROPERTIES OF "VERMIWASH", NATURAL PLANT GROWTH SUPPLEMENT FOR TEA, COCONUT AND HORTICULTURAL CROPS

Earthworms have been well exploited in agriculture worldwide inmaximizing crop production for many years. Amongst vermin-technology(Vermitech) practices, Vermiwash (Vw) has shown its field efficacy withmany crops. Vw is the wash of earthworm's celomic fluid and calcareouslayer and the watery extract of the bedding materials, which is known tocontain ample amounts of soluble macro and micronutrients, natural growthhormones, beneficial microbes, vitamins and amino acids etc. andnematicidal properties. However, the attributes to beneficial agronomicvalues of Vw have not yet been scientifically validated fully although thispractice is extensively being expanded in India and Sri Lanka. Therefore, thepresent study investigated the biological and chemical properties of elevensources of Vw resulted from different earthworm species and raw materials indifferent farms in Sri Lanka. Vw was tested as a source for hydroponics forlettuce in comparison with the Albert solution. The efficacy of regular foliarand soil applications of Vw on bush bean (Variety: Top crop), tomato(Variety: Thilina), nursery tea (cultivar: TRI 4071) and coconut (Variety:DxT) was also evaluated in comparison with vermicompost and conventionalchemical inputs in a series of bioassays.The results of analyses revealed varying levels of biological and chemicalproperties of the test samples but within the optimal range for plant growth.Vw exhibited significantly lower levels of N, P, K but was rich in Ca, Mg,Zn, Fe and Mn; pH and CEC were also in the required ranges. Vwsignificantly (p=0.05) influenced the soil microbial biomass althoughindividual microorganisms were not identified; microbial biomass of Vw andcontrol were estimated as 4.95 and 3.20 x 10-3 mg C02/day/25g soilrespectively. Vw proved as a better alternate source to Albert solution forlettuce growth under hydroponic culture. The root length, root and shootbiomass and total leaf area of bush bean were significantly (p=0.05) affectedby Vw application compared to that of vermin-compost and synthetic fertilizer treatments. In nursery tea, Vw application lead to comparativelygreater callusing of tea cuttings but the increase in root formation and shootgrowth was not significant. Vw application boosted growth of coconutseedlings. However, no positive responses were seen with tomato.The data suggested the potential exploitation of Vw in home gardening,indoor and container planting, biodynamic and organic farming etc. as afarmer friendly, culturally sensitive and economically viable natural product.Further work on attributes to plant growth such as determination of growthhormones, different doses and mass production of uniform quality Vw usingdifferent earthworm species and raw materials etc. would strengthen itssustainable use as an alternative growth supplement

Overexpression of aromatase associated with loss of heterozygosity of the STK11 gene accounts for prepubertal gynecomastia in boys with Peutz-Jeghers Syndrome

Context: Peutz-Jeghers syndrome (PJS) is an autosomal-dominant disorder that arises as a consequence of mutations in the STK11 gene that encodes LKB1. PJS males often have estrogen excess manifesting as gynecomastia and advanced bone age. We and others have previously described an increase in testicular aromatase expression in PJS patients. However, the underlying mechanism has not yet been explored. Objective: The aim of this study was to characterize the role of LKB1 in regulating the expression of aromatase in boys with PJS via signaling pathways involving AMP-activated protein kinase (AMPK) and cyclic AMP-responsive element binding protein-regulated transcription coactivators (CRTCs). Patients: We studied testicular biopsies from two boys with STK11 mutations: a 13-year-old boy and an unrelated 4-year-old boy with prepubertal gynecomastia and advanced bone age, as well as breast tissue from the 13-year-old boy. Results: Loss of heterozygosity of STK11, measured by the absence of LKB1 immunofluorescence, was observed in Sertoli cells of abnormal cords of testis samples from affected individuals. This was associated with loss of p21 expression and decreased phosphorylation of AMPK, known downstream targets of LKB1, as well as the increased expression of aromatase. Similar results of low LKB1 expression in cells expressing aromatase were observed in the mammary epithelium from one of these individuals. Nuclear expression of the CRTC proteins, potent stimulators of aromatase and known to be inhibited by AMPK, was significantly correlated with aromatase. Conclusions: Loss of heterozygosity of the STK11 gene leads to an increase in aromatase expression associated with an increase in CRTC nuclear localization, thereby providing a mechanism whereby PJS results in increased endogenous estrogens in affected males