The retinal pigment epithelium (RPE) transports nutrients and metabolites between the microvascular bed that maintains the outer retina and photoreceptor neurons. The RPE removes photoreceptor outer segments (POS) by receptor-mediated phagocytosis, a process that peaks in the morning. Uptake and degradation of POS initiates signaling cascades in the RPE. Upstream stimuli from various metabolic activities converge on mechanistic target of rapamycin complex 1 (mTORC1), and aberrant mTORC1 signaling is implicated in aging and age-related degeneration of the RPE. In the current study, we measured mTORC1-mediated responses to RPE phagocytosis in vivo and in vitro. During the morning burst of POS shedding, there was transient activation of mTORC1-mediated signaling in the RPE. POS activated mTORC1 through lysosome-independent mechanisms and engulfed POS served as a docking platform for mTORC1 assembly. The identification of POS as endogenous stimuli of mTORC1 in the RPE provides a mechanistic link underlying the photoreceptor-RPE interaction in the outer retina.

Precise regulation of synapses during development is essential to ensure accurate neural connectivity and function of nervous system. Many signaling pathways, including the mTOR (mechanical Target of Rapamycin) pathway operate in neurons to maintain genetically determined number of synapses during development. mTOR, a kinase, is shared between two functionally distinct multi-protein complexes- mTORC1 and mTORC2, that act downstream of Tuberous Sclerosis Complex (TSC). We and others have suggested an important role for TSC in synapse development at the Drosophila neuromuscular junction (NMJ) synapses. In addition, our data suggested that the regulation of the NMJ synapse numbers in Drosophila largely depends on signaling via mTORC2. In the present study, we further this observation by identifying Tricornered (Trc) kinase, a serine/threonine kinase as a likely mediator of TSC signaling. trc genetically interacts with Tsc2 to regulate the number of synapses. In addition, Tsc2 and trc mutants exhibit a dramatic reduction in synaptic levels of WASP, an important regulator of actin polymerization. We show that Trc regulates the WASP levels largely, by regulating the transcription of WASP. Finally, we show that overexpression of WASP (Wiskott-Aldrich Syndrome Protein) in trc mutants can suppress the increase in the number of synapses observed in trc mutants, suggesting that WASP regulates synapses downstream of Trc. Thus, our data provide a novel insight into how Trc may regulate the genetic program that controls the number of synapses during development.

Purpose Presently, there are six undergraduate HRSA-funded MCH pipeline training programs (MCHPTP) in the nation and they have gained significant momentum since inception by recruiting, training and mentoring undergraduate students in a comprehensive MCH-focused approach. This article describes the outcomes from the 6 training programs; and primarily Baylor College of Medicine–Texas Southern University (BCM–TSU’s) collaborative strategy focusing on the MCH research training and outcomes, which align with HRSA’s MCH bureau’s missions. Description Each MCHPTP offers trainees interdisciplinary MCH research experiences through intra/inter-institutional collaborations and partnerships, but BCM–TSU’s MCHPTP was the only one with the primary focus to be research. As a case study, the BCM–TSU Program developed an innovative research curriculum integrated with MCH Foundations Course that comprised 2 hour weekly meetings. Students were split into collaborative research groups of 4–5 students, with multidisciplinary peer-mentors, clinical fellows and MCH research faculty from institutions at the world—renowned Texas Medical Center. Assessment Since the inception of the MCH mentorship programs, all six MCHPTPs have enrolled up to 1890 trainees and/or interns. BCM–TSU Program trainees are defined as undergraduate students in their 1st or 2nd year of college while research interns are upper classmen in their 3rd or 4th year of college. The case study showed that BCM–TSU Program trainees demonstrated outstanding accomplishments in the area of research through primary and co-authorships of 13 peer-reviewed journal publications by 78 trainees, over a period of 3 years, in addition to dozens of presentations at local, regional and national conferences. Conclusions The research productivity of students in the six MCHPTPs is strongly indicative of the success of integrating MCH research mentoring into MCH didactic training. The development of a diverse and robust MCH mentorship program promotes and strengthens research activities in areas of high priority such as addressing health disparities in MCH morbidity and mortality in the U.S.