Project description:Chronic, progressive retinal diseases, such as age-related macular degeneration (AMD), diabetic retinopathy, and retinitis pigmentosa, arise from genetic and environmental perturbations of cellular and tissue homeostasis. These disruptions accumulate with repeated exposures to stress over time, leading to progressive visual impairment and, in many cases, legal blindness. Despite decades of research, therapeutic options for the millions of patients suffering from these disorders remain severely limited, especially for treating earlier stages of pathogenesis when the opportunity to preserve the retinal structure and visual function is greatest. To address this urgent, unmet medical need, we employed a systems pharmacology platform for therapeutic development. Through integrative single-cell transcriptomics, proteomics, and phosphoproteomics, we identified universal molecular mechanisms across distinct models of age-related and inherited retinal degenerations, characterized by impaired physiological resilience to stress. Here, we report that selective, targeted pharmacological inhibition of cyclic nucleotide phosphodiesterases (PDEs), which serve as critical regulatory nodes that modulate intracellular second messenger signaling pathways, stabilized the transcriptome, proteome, and phosphoproteome through downstream activation of protective mechanisms coupled with synergistic inhibition of degenerative processes. This therapeutic intervention enhanced resilience to acute and chronic forms of stress in the degenerating retina, thus preserving tissue structure and function across various models of age-related and inherited retinal disease. Taken together, these findings exemplify a systems pharmacology approach to drug discovery and development, revealing a new class of therapeutics with potential clinical utility in the treatment or prevention of the most common causes of blindness.
Project description:To determine the gene expression changes in the retina of Abca4-/-Rdh8-/- (dKO) mice, we collected retina samples from dKO animals under various experimental conditions, generated single-cell suspensions, and performed scRNA-Seq (10X Genomics).
Project description:VAMP7 is involved in autophagy and exocytosis mediating neurite growth, two yet unconnected cellular pathways. Here we show the occurrence of combined VAMP7/ATG9 secretory events. VAMP7 localized, together with LC3 and ATG9, in vesicles moving anterogradely along the axon towards growth cones. VAMP7 knockout disrupted the autophagy response to drugs and starvation. Release of extracellular vesicles triggered by autophagy was impaired in VAMP7-knockout cells and autophagy-deficient cells were impaired in VAMP7 exocytosis. Secretomics showed that VAMP7-knockout cells were impaired in unconventional secretion of cytoplasmic, exosomal and mitochondrial proteins. We further found that autophagy stimulated neurite growth in a VAMP7-dependent manner. Furthermore, neurons still grew long axons in nutrient-restricted conditions and when treated with autophagy-inducing drugs. A nanobody directed against VAMP7 inhibited the effect of nutrient restriction. We propose that VAMP7-dependent autophagic secretion contributes to a resilience mechanism to preserve axonal growth in restriction conditions, as part of brain sparing occurring in growth restriction.
Project description:Analysis of MDA-MB-231 breast tumor cell from knocking-down phosphodiesterase 3A (PDE3A), a cyclic nucleotide phosphodiesterase. Results provide insight into the role of PDE3A in breast tumor progression and metastasis.
Project description:Background: Examining transcriptional regulation by existing antidepressants in key neural circuits implicated in depression, and understanding the relationship to transcriptional mechanisms of susceptibility and natural resilience, may help in the search for new therapeutics. Further, given the heterogeneity of treatment response in human populations, examining both treatment response and non-response is critical. Methods: We compared the effects of a conventional monoamine-based tricyclic antidepressant, imipramine (14 daily injections), and a rapidly acting, experimental, non-monoamine-based antidepressant, ketamine (single injection), in mice subjected to chronic social defeat stress, a validated model of depression, and used RNA-sequencing to analyze transcriptional profiles associated with susceptibility, resilience and antidepressant response and non-response in prefrontal cortex (PFC), nucleus accumbens, hippocampus, and amygdala. Results: We identified approximately equal numbers of responder and non-responder mice following ketamine or imipramine treatment. Ketamine induced more expression changes in hippocampus than other brain regions; imipramine induced more expression changes in nucleus accumbens and amygdala. Transcriptional profiles in ketamine and imipramine responders were most similar in PFC, where the least transcriptional regulation occurred for each drug. Non-response reflected both the lack of response-associated gene expression changes and unique gene regulation. In responders, both drugs reversed susceptible associated transcriptional changes as well as induced resilient associated transcription in PFC, with effects varying by drug and brain region studied. Conclusions: We generated a uniquely large resource of gene expression data in four inter-connected limbic brain regions implicated in depression and its treatment with imipramine or ketamine. Our analyses highlight the PFC as a key site of common transcriptional regulation by both antidepressant drugs and in both reversing susceptibility and inducing resilience associated molecular adaptations. In addition, we found region-specific effects of each drug suggesting both common and unique effects of imipramine versus ketamine. mRNA profiles of susceptibility to chronic social defeat stress as well as treatment response were generated across 4 separate brain regions, with a sample size of 3-5 per group.
Project description:Endogenous glucocorticoids (GCs) are pivotal in controlling inflammation. Keratinocyte-derived GCs contribute to local skin homeostasis as deletion of the GC-producing enzyme 11β-hydroxylase (Cyp11b1) in keratinocytes exacerbated skin inflammation. Since local tamoxifen-induced knockout (KO) induction may contribute to skin irritation, we implemented intraperitoneal injections to induce a systemic skin GC depletion preventing experimental skin irritation in order to reveal the importance of skin GC in steady-state. Both, local and systemic skin GC deficiency models exhibited reduced skin GC levels and increased migration of skin antigen-presenting cells to draining lymph nodes. However, systemic skin GC ablation did not result in pronounced skin inflammation as seen in local model. Interestingly, systemic skin GC deficiency elevated systemic inflammatory markers and provoked adrenal GC synthesis. RNA sequencing of keratinocytes revealed distinct gene expression patterns between local and systemic KOs. Local skin GC ablation showed a stronger inflammatory and apoptotic response, while systemic skin GC deficiency triggered several compensatory regulatory pathways, mitigating extensive skin inflammation. These findings underscore the critical role of local GCs in skin immune resilience against minor skin irritations and highlight the interplay between skin and adrenal GC levels.
Project description:Alzheimer’s disease (AD), the leading cause of dementia, affects millions of people worldwide. With no disease-modifying medication currently available, the human toll and economic costs are rising rapidly. Under current standards, a patient is diagnosed with AD when both cognitive decline and pathology (amyloid plaques and neurofibrillary tangles) are present. Remarkably, some individuals who have AD pathology remain cognitively normal. Uncovering factors that lead to “cognitive resilience” to AD is a promising path to create new targets for therapies. However, technical challenges discovering novel human resilience factors limit testing, validation, and nomination of novel drugs for AD. In this study, we use single-nucleus transcriptional profiles of postmortem cortex from human individuals with high AD pathology who were either cognitively normal (resilient) or cognitively impaired (susceptible) at time of death, as well as mouse strains that parallel these differences in cognition with high amyloid load. Our cross-species discovery approach highlights a novel role for excitatory layer 4/5 cortical neurons in promoting cognitive resilience to AD, and nominates several resilience genes that include ATP1A1, GRIA3, KCNMA1, and STXBP1. This putative cell type has been implicated in resilience in previous studies on bulk RNA-seq tissue, but our single-nucleus and cross-species approach identifies particular resilience-associated gene signatures in these cells. These novel resilience candidate genes were tested for replication in orthogonal data sets and confirmed to be correlated with cognitive resilience. Based on these gene signatures, we identified several potential mechanisms of resilience, including regulation of synaptic plasticity, axonal and dendritic development, and neurite vesicle transport along microtubules that are potentially targetable by available therapeutics. Because our discovery of resilience-associated genes in layer 4/5 cortical neurons originates from an integrated human and mouse transcriptomic space from susceptible and resilient individuals, we are positioned to test causality and perform mechanistic, validation, and pre-clinical studies in our human-relevant AD-BXD mouse panel.