Biology subjects

Molina, L. M.

Publications and source records attributed to Molina, L. M..

3 recordsLinked to original sources

bioRxiv2023

Siglecs in the Porcine Oviduct and Sialylated Ligands on Sperm: Roles in the Formation of the Sperm Reservoir

AbstractDuring mammalian insemination, most of the deposited sperm are lost by retrograde flow or the female reproductive tracts immune response. Once semen enters the uterus, seminal fluid and sperm elicit leukocyte infiltration that contributes to the elimination of sperm in the uterus. However, unlike the uterus, invading sperm do not trigger a phagocytic response in the oviduct in the absence of dysfunction or disease states. Thus, the oviduct possesses a distinct immunological microenvironment that tolerates sperm while maintaining the capacity to respond to pathogens. It has been suggested that sperm glycocalyx contributes to innate oviductal tolerance, but the cell and molecular mechanisms are not understood. The current investigation focused on the role of sialic acid-containing glycoconjugates on sperm and their potential to elicit innate tolerance via cognate sialic acid-binding immunoglobulin-type lectins (Siglecs) expressed in the oviduct. In this manuscript, we report our discovery of eight Siglecs (Siglecs-1, -2, -3, -5, -10, -11, -14, -15) expressed in the lower pig oviduct, five of which are known for immune inhibitory functions (Siglecs-2, -3, -5, -10, and -11) and how these may play a role in achieving sperm-induced immune suppression in the oviduct microenvironment. Mass spectrometry profiling of porcine sperm revealed the presence of a mixture of 2,3 and 2,6 linked sialic acids with 2,3-linked sialic acids as the dominant linkage. Of the detected glycans, several sialic acid-containing glycoconjugates were identified as potential ligands for Siglecs (among O-linked glycans: NeuAc1GalNAc1, NeuGc1GalNAc1, NeuAc2Gal1GalNAc1; attached to glycolipids: NeuAc2Gal1GalNAc1Gal1Glc1, Fuc1Gal1GalNAc1NeuAc1Gal1Glc1). This is the first report of Siglec expression in the mammalian oviduct and total glycan analysis of porcine sperm. The results of this study reveal the potential for a sperm-sialoglycan and oviductal-Siglec axis that may contribute to the distinct immunophysiology of the oviduct fundamentally required for undisrupted reproduction in mammals.

biochemistry↗

bioRxiv2020

NOTCH-YAP1/TEAD-DNMT1 axis regulates hepatocytereprogramming into intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC), a disease of poor prognosis, has increased in incidence. It is challenging to treat due to intra- and inter-tumoral heterogeneity, which in part is attributed to diverse cellular origin. Indeed, co-expression of AKT and NICD in hepatocytes (HCs) yielded ICC, with similarity to proliferative, Notch-activated, and stem cell-like subclasses of clinical ICC. NICD regulated SOX9 and YAP1 during ICC development. Yap1 deletion or TEAD inhibition impaired HC-to-biliary epithelial cell (BEC) reprogramming and ICC proliferation; Sox9 loss repressed tumor growth; and Yap1-Sox9 combined loss abolished ICC development in AKT-NICD model. DNMT1 was discovered as a novel downstream effector of YAP1-TEAD complex that directed HC-to-BEC/ICC fate-switch. DNMT1 loss prevented Notch-dependent HC-to-ICC development, and DNMT1 re-expression restored ICC development following TEAD repression. Coexpression of DNMT1 with AKT was sufficient to induce hepatic tumor development including ICC. Thus, we have identified a novel NOTCH-YAP1/TEAD-DNMT1 axis essential for HC-driven ICC development. SIGNIFICANCEWe evaluated the clinical relevance of hepatocyte-driven ICC model and revealed critical but distinct roles of YAP1 and SOX9 in AKT-NICD-driven hepatocyte-derived ICC. We also identified NOTCH-YAP1/TEAD-DNMT1 axis as a critical driver for hepatocyte-to-ICC reprogramming, which might have biological and therapeutic implications in ICC subsets.

cancer biology↗

bioRxiv2020

Compensatory hepatic adaptation accompanies permanent absence of intrahepatic biliary network due to YAP1 loss in liver progenitors

YAP1 regulates cell plasticity during liver injury, regeneration and cancer, but its role in liver development is unknown. YAP1 activity was detected in biliary cells and in cells at the hepato-biliary bifurcation in single-cell RNA-sequencing analysis of developing livers. Hepatoblast deletion of Yap1 led to no impairment in Notch-driven SOX9+ ductal plate formation, but prevented the formation of the abutting second layer of SOX9+ ductal cells, blocking the formation of a patent intrahepatic biliary tree. Intriguingly, the mice survived for 8 months with severe cholestatic injury and without any hepatocyte-to-biliary transdifferentiation. Ductular reaction in the perihilar region suggested extrahepatic biliary proliferation likely seeking the missing intrahepatic biliary network. Long-term survival of these mice occurred through hepatocyte adaptation via reduced metabolic and synthetic function including altered bile acid metabolism and transport. Overall, we show YAP1 as a key regulator of bile duct development while highlighting a profound adaptive capability of hepatocytes.

pathology↗