University Of Connecticut Sch Of Med/Dnt

NIH Research Projects · FY 2024 · 2011-05

Abstract Alzheimer's disease (AD) is the most common age-dependent neurodegenerative disease with progressive impairment in synaptic and cognitive functions occurred early in the disease course. For past three decades, various hypotheses are proposed to determine the cause of AD pathogenesis. The amyloid hypothesis is being tested most extensively in the field because of strong supports from human genetic and epidemiological studies. The main essence of hypothesis is that the abnormal level of β- amyloid peptide (Aβ) leads to sequential pathological developments that eventually cause a potential of synaptic and cognitive dysfunctions in AD patients. Consistently, deletion or inhibition of BACE1, which is a sole enzyme for cleaving amyloid precursor protein (APP) at the β-secretase site to initiate the generation of Aβ, reduces Aβ production and amyloid pathology. Brain penetrable inhibitors are tested in clinical trials but fail to improve cognitive functions in AD patients, resulting in the early termination of clinical trials. We and others show that BACE1 regulates synaptic plasticity and clinical used BACE1 inhibitors actually impair synaptic function at a clinically tested dose. In this proposal, we aim to find solutions that will take the advantage of this plaque reduction and can overcome the unwanted side effects associated with worsening cognitive functions/scores. Our goal is to develop strategy that improve synaptic functions in association with BACE1 inhibition in AD patients. We will test our central hypothesis that BACE1 inhibitors will be more effective for AD treatment if BACE1-mediated synaptic impairment is under controls. Two specific aims are proposed to test our hypothesis: Aim 1 is to differentiate toxic Aβ-mediated and BACE1-mediated synaptic impairments in mouse models. Aim 2 is to determine whether mGluR1 positive allosteric modulator will improve AD and BACE1-mediated synaptic impairment. The ultimate goal is to optimize the use of BACE1 inhibitors and supplement with synaptic enhancer such as a positive allosteric modulator (PAM) of metabotropic glutamate receptor-1 (mGluR1) in AD mice. Our preliminary studies support shows improved long term potentiation in BACE1-null mice treated with an mGluR1 PAM. Knowledge gained from this study will guide the future clinical application of BACE1 in human.

NIH Research Projects · FY 2026 · 2011-02

There is an urgent clinical need to develop new therapeutics to promote healing of bone. While most bone injuries heal, many do not, particularly large defects. Understanding cellular signaling mechanisms that regulate normal healing, can lead us to new therapeutic targets. Notch signaling regulates the expansion and differentiation of mesenchymal progenitor cells (MPC) and regulates vascularization of many tissues, including bone. Our studies, and published studies from other investigators, show that Notch signaling is a key regulatory pathway during bone healing. Indeed, our preliminary and published results show that increasing Notch signaling in MPCs improves bone regeneration, and that global inhibition of Notch using various models, deleteriously impacts healing. To sufficiently advance our understanding of Notch signaling in bone healing, and translate these mechanistic observations, will require robust experimentation, including preclinical studies in relevant injury models. Our long-term goal is to develop a clinically relevant approach to increase Notch signaling that enhances bone healing. We hypothesize that Notch signaling promotes expansion of MPCs and callus vascularization, leading to enhanced bone formation. We will interrogate the Notch signaling pathway during bone healing to reveal a deeper understanding of ligands and receptors that are at play during healing, and the cell-type specific expression of these signaling components. This work will be completed in two specific Aims, using state of the art mouse models. In the first Aim, we will study the role of Notch ligands. Our work has previously demonstrated that Jagged1 is the dominant Notch ligand expressed in MPCs and the osteochondrogenic lineage. We will disrupt Jag1 specifically in MPCs, chondrocytes, osteoblasts and osteocytes in the callus during fracture healing. Additionally, as Jag1 and Dll4 produced by endothelial cells regulate vascularization, we will determine which is the dominant ligand regulating vascularization using conditional deletion of both ligands from endothelial cells using Cdh5-CreER. A spectrum of fracture healing outcomes, including vascularization, as well as effects on endothelial cell and MPC proliferation and MPC differentiation will be determined in vivo. We will capitalize on our extensive experience using inducible Cre mice to ensure normal development thereby by-passing developmental effects of ligand disruption. These studies will be complemented with a translational study in which Jag1 protein, alone or in combination with an existing therapy, BMP2, will be delivered during healing of critical sized femoral defects. In the second Aim, we will examine the role of Notch receptors on MPC and endothelial cells using Notch1 or Notch2 floxed mice. We will determine whether these receptors are critical for defect healing driven by BMP2 or Jag1. This study will significantly advance the field by clarifying the cell-specific role of ligand and receptor during bone healing, and provide the preclinical relevance for local activation Notch signaling to increase bone defect healing.

NIH Research Projects · FY 2026 · 2009-12

The BK channel (also known as Slo1) is almost ubiquitously expressed in the body with many important physiological functions, such as regulating neurotransmitter release by acting at presynaptic sites of neurons. Mutations of the channel may cause diverse diseases. Physiological functions of Slo1 depend to great degrees on its expression level in the cell membrane and interactions with regulatory proteins. Genetic screen for mutants that suppress a sluggish phenotype caused by a hyperactive Slo1 in C. elegans led to the identification of two proteins required for Slo1 physiological functions in vivo, including a melatonin receptor and an ubiquitin E3 ligase. Electrophysiological and behavioral analyses indicate that Slo1 mediates melatonin’s sleep-promoting effect in worms, and that Slo1’s physiological roles in regulating neurotransmitter release and sleep depend on melatonin secretion and activation of the melatonin receptor. In a heterologous expression, human Slo1 is activated by melatonin through the MT1 but not MT2 melatonin receptor. However, it remains to be determined where Slo1 acts in the nervous system to regulate sleep in worms, and whether mammalian Slo1 in native neurons may be also activated by melatonin through a specific melatonin receptor. Mass spectrometry analyses identified a protein greatly increased in mutants of the E3 ligase compared with wild type. Mutations of the gene encoding this protein led to increased Slo1 function, suggesting that it is a novel inhibitory regulator of Slo1, and that the E3 ligase regulates Slo1 by facilitating degradation of this putative inhibitory regulator. Further studies are needed to define a molecular pathway through which the E3 ligase regulates Slo1. This project is to investigate 1) how the E3 ligase regulates Slo1 through the inhibitory regulator and other proteins; 2) where and how Slo1 acts in the nervous system to regulate sleep in C. elegans; and 3) why MT1 but not MT2 may allow Slo1 activation by melatonin in the heterologous expression system, and whether melatonin can also regulate Slo1 in mouse brain through MT1 but not MT2. We will answer these questions using a combination of electrophysiological, genetic, cellular, and molecular biological approaches. Results of the proposed studies are expected to produce important new knowledge about how Slo1 interacts with other proteins to regulate cellular excitability, neurotransmitter release, and behavior.

NIH Research Projects · FY 2024 · 2005-01

Alzheimer’s disease (AD) is characterized by the presence of extracellular neuritic plaques and intraneuronal neurofibrillary tangles. In addition to amyloid plaques and neurofibrillary tangles, the presence of dystrophic neurites (DNs), referring to aberrant neuritic sprouting as well as swollen dendrites and/or axons, is known as one pathological feature in surrounding amyloid plaques on AD postmortem brains, and has been shown to correlate with cognitive dysfunctions in AD. With the increasing number of failures in clinical trials that target the formation of amyloid deposition, AD treatment is recognized to be extremely challenging. This study aims to explore the approach for preventing or reducing DNs. We have previously demonstrated that reticulon proteins, mainly RTN3 but not RTN1, are massively accumulated in DNs in surrounding neuritic but not diffuse amyloid plaques. RTN3+ DNs contain mainly clustered tubular endoplasmic reticulum (ER). To build around this finding, we have recently discovered through our various morphological characterizations that ATG9A‐positive DNs (ATG9A+ DNs) form near the core plaques while RTN3+ DNs form subsequently and can surround ATG9A+ DNs. ATG9A is a critical molecule required not only for pre‐autophagosome formation but also for autophagosome elongation and maturation. DNs, enriched with multibody vesicles and marked by the autophagy protein LC3 and RAB7 or ubiquitin, are usually distributed relatively farthest from the core amyloid plaque and develop the latest in our temporal study. In light of growing knowledge in this area, we propose to advance our study further by testing the hypothesis in this renewal application that aging and amyloid deposition induces ATG9A‐mediated abnormal trafficking and subsequent tubular ER clustering and autophagic dysfunctions in AD brains. Two specific aims are proposed to test this hypothesis: 1) Aim 1 is to investigate the effects of amyloid pathology on ATG9A trafficking and the underlying mechanism; 2) Aim 2 is to determine the role of microglia in mediating growth of dystrophic neurites in surrounding amyloid plaques. Overall, this renewal proposal has a set of readily achievable experiments that focus on the growth of various form of DNs and functional relationship between reticulon proteins and ATG9A in AD pathogenesis. We will also explore molecular targets for reducing or preventing formation of DNs for the ultimate purpose of improving cognitive functions. Such a study will yield critical knowledge that may guide therapeutic applications for decreasing DN formation and cognitive dysfunction in AD patients.

NIH Research Projects · FY 2026 · 1980-07

This renewal application is for five years of continued support of the Postdoctoral Training Program in Alcohol Studies at the University of Connecticut School of Medicine (UConn Health). The program was established in 1980 and evolves with this renewal with transitions and additions among training faculty and new resources to meet the needs of the next generation of scientists committed to understanding and reducing harms from alcohol use and related consequences. To accomplish this, this program takes a collaborative, interdisciplinary, and cross-campus (UConn Health, University of Connecticut (UConn-Storrs)) approach with faculty representing numerous departments including psychiatry, computer science and engineering, behavioral sciences and community health, medicine, and public health sciences. Our program continues to be focused on alcohol. It also recognizes that alcohol use, intervention and treatment often occur in the context of other substance use and comorbidities, and program faculty have substantial expertise in these areas. Moreover, there is new attention to training opportunities in: mentoring, structural and interpersonal factors in alcohol use and misuse; data science; mobile technologies; and social media research. Further, while training faculty have considerable experience in mentoring, supplemental training in best practices in mentoring and contemporary issues is planned, for faculty and trainees. Throughout, an Executive Advisory Committee composed of internal and external members will contribute to program oversight and evaluation. This program provides three postdoctoral fellows with individualized and multimodal training for typically two and up to three years. Fellows will select from four Core Research Areas in clinical and translational research: (1) Intervention, Treatment and Recovery; (2) Etiology, Risk Factors and Comorbidities, (3) Health Services, Implementation Science, and Translational research, and (4) Gut Microbiome, Liver Disease and Immunology. Our Addiction Science and Principles of Clinical and Translational Research curriculums are examples of formal coursework. Faculty collaborators and opportunities at external institutions will be available to extend training further. Fellows will be assigned a primary and possibly a secondary mentor, based on similar research interests across the core and elective areas. The primary mentor will provide instruction in methods, design, analysis, and ethics of alcohol research within the trainee's core research area(s) and lead the trainee’s progress on achieving program and personal professional milestones. Secondary mentors will do the same for their research area. Expectations for trainees will be to: 1) produce at least two first authored publications per year of training, 2) initiate and complete an independent or collaborative research project, 3) present research at RSA and other scientific conferences, and 4) prepare a grant application by the end of the training period. Given our successes in these objectively measured standards with recent trainees, this program is well-poised to train the next generation of alcohol researchers.