ORP9 Knockdown Delays the Maturation of Junction Related Endocytic Structures in the Testis and Leads to Impaired Sperm Release †.

ORP9 Knockdown Delays the Maturation of Junction Related Endocytic Structures in the Testis and Leads to Impaired Sperm Release†. Biol Reprod. 2020 Sep 09;: Authors: Adams A, Vogl W Abstract The release of late spermatids from the seminiferous epithelium requires the internalization of intercellular junctions by Sertoli cell specific structures called 'tubulobulbar complexes' (TBCs). These large, endocytic devices likely evolved from classic clathrin-mediated endocytosis machinery (CME), but have several important morphological differences to CME vesicles. Most notable among these differences is that extensive endoplasmic reticulum (ER) membrane contact sites (MCSs) occur with TBCs and not with clathrin coated pits. One of the well-established functions of ER MCSs is lipid exchange. Previously, we have established that the ORP9 lipid exchange protein is localized to the TBC-ER MCS; however, the function of ORP9 and lipid exchange at the sites is not known. Here we use an in vivo knockdown approach to probe function. The testes of Sprague-Dawley rats were injected with ORP9 targeted siRNA or non-targeted reagents, and the tissues examined by bright field, super-resolution (STED), and electron microscopy. Knockdown of ORP9 was achieved and maintained with daily injections of siRNA for 2-3 day intervals. Compared to controls, sections from ORP9 siRNA injected testes had longer TBC tubes and fewer fused TBC bulbs. Late spermatids were...
Source: Biology of Reproduction - Category: Reproduction Medicine Authors: Tags: Biol Reprod Source Type: research