Age-related macular degeneration (AMD) is the leading cause of blindness in elderly people, with limited treatment options available for most patients. AMD involves the death of retinal pigment epithelium (RPE) and photoreceptor cells, with mitochondria dysfunction being a critical early event. In the current study, we utilized our unique resource of human donor RPE graded for AMD presence and severity to investigate proteome-wide dysregulation involved in early AMD. Organelle-enriched fractions of RPE were isolated from donors with early AMD (n = 45) and healthy age-matched controls (n = 32) and were analyzed by UHR-IonStar, an integrated proteomics platform enabling reliable and in-depth proteomic quantification in large cohorts. A total of 5941 proteins were quantified with excellent analytical reproducibility, and with further informatics analysis, many biological functions and pathways were found to be significantly dysregulated in donor RPE samples with early AMD. Several of these directly pinpointed changes in mitochondrial functions, e.g., translation, ATP metabolic process, lipid homeostasis, and oxidative stress. These novel findings highlighted the value of our proteomics investigation by allowing a better understanding of the molecular mechanisms underlying early AMD onset and facilitating both treatment development and biomarker discovery.

Although traumatic brain injury (TBI) causes hospitalizations and mortality worldwide, there are no approved neuroprotective treatments, partly due to a poor understanding of the molecular mechanisms underlying TBI neuropathology and neuroprotection. We previously reported that the administration of low-dose methamphetamine (MA) induced significant functional/cognitive improvements following severe TBI in rats. We further demonstrated that MA mediates neuroprotection in part, via dopamine-dependent activation of the PI3K-AKT pathway. Here, we further investigated the proteomic changes within the rat cortex and hippocampus following mild TBI (TM), severe TBI (TS), or severe TBI plus MA treatment (TSm) compared to sham operated controls. We identified 402 and 801 altered proteins (APs) with high confidence in cortical and hippocampal tissues, respectively. The overall profile of APs observed in TSm rats more closely resembled those seen in TM rather than TS rats. Pathway analysis suggested beneficial roles for acute signaling through IL-6, TGFβ, and IL-1β. Moreover, changes in fibrinogen levels observed in TSm rats suggested a potential role for these proteins in reducing/preventing TBI-induced coagulopathies. These data facilitate further investigations to identify specific pathways and proteins that may serve as key targets for the development of neuroprotective therapies.

Tuft cells (TCs) are rare chemosensory epithelial cells that regulate mucosal homeostasis in multiple organs, but their role in salivary gland (SG) biology remains poorly defined. This study aimed to define TC structure in mice submandibular glands (SMGs), determine how TC loss affects gland organization and function, and evaluate whether TC abundance in human minor SGs is associated with Sjögren’s disease (SjD) features. Specifically, TC ultrastructure and ductal localization were characterized in female and male C57BL/6J mouse SMGs by transmission electron microscopy and immunostaining. Wild-type and C57BL/6J-Pou2f3^-/- (TC-deficient mouse strain) SMGs were analyzed by histology and bulk RNA-seq, and salivary function was assessed by saliva flow and proteomics. Human minor SG biopsies from SjD and non-Sjögren sicca (nSjD) patients were analyzed by immunostaining and Poisson regression. In mice SMGs, TCs showed conserved ultrastructural features and localization in both sexes. TC loss was associated with marked sex-biased transcriptome remodeling, morphological disruption, and altered saliva quantity and quality. In humans, TC counts differed between nSjD and SjD groups and were associated with salivary flow, serologic status, and histopathologic features. These findings support a role for TCs in SG epithelial integrity and suggest TC abundance as a candidate biomarker of SG dysfunction.