Acute ischemic stroke (AIS) is caused by clotting in the cerebral arteries, leading to brain oxygen deprivation and cerebral infarction. Recombinant human tissue plasminogen activator (tPA) is currently the only FDA-approved drug for ischemic stroke. However, tPA has to be administered within 4.5 h from the disease onset and delayed treatment of tPA can increase the risk of neurovascular impairment, including neuronal cell death, blood-brain barrier (BBB) disruption, and hemorrhagic transformation. A key contributing factor for tPA-induced neurovascular impairment is activation of matrix metalloproteinase-9 (MMP-9). We used a clinically-relevant mouse embolic model of focal-cerebral ischemia by insertion of a single embolus of blood clot to block the right middle cerebral artery. We showed that administration of the potent and highly selective gelatinase inhibitor SB-3CT extends the time window for administration of tPA, attenuating infarct volume, mitigating BBB disruption, and antagonizing the increase in cerebral hemorrhage induced by tPA treatment. We demonstrated that SB-3CT attenuates tPA-induced expression of vascular MMP-9, prevents gelatinase-mediated cleavage of extracellular laminin, rescues endothelial cells, and reduces caveolae-mediated transcytosis of endothelial cells. These results suggest that abrogation of MMP-9 activity mitigates the detrimental effects of tPA treatment, thus the combination treatment holds great promise for extending the therapeutic window for tPA thrombolysis, which opens the opportunity for clinical recourse to a greater number of patients. Significance Statement Endovascular thrombectomy benefited patients with disproportionately severe clinical deficit relative to infarct volume and provides a surgical option for treatment of ischemic stroke. Tissue-plasminogen activator (tPA) is the only FDA-approved clot-dissolving drug for treatment of ischemic stroke. However, its beneficial effect is seen only within 4.5 hours from the onset of stroke, with better outcomes observed the sooner treatment is given. Major risk is MMP-9−mediated neurovascular impairment. We document that early administration of the pharmacological agent SB₃CT reduces MMP-9 levels and mitigates the side effects associated with tPA. Furthermore, it extends the time window for treatment with tPA after stroke holding great potential for both disease intervention and benefiting patients who might not otherwise be candidates for treatment with tPA.

Mild traumatic brain injury (mTBI) is a leading cause of long-term disability. Following mTBI, secondary chemical cascades and neuroinflammation can result in myelin damage, significantly impairing cognitive function. This study aims to assess demyelination in mice with mTBI induced by open-field low-intensity blast (LIB) using a novel three-dimensional short repetition time adiabatic inversion recovery UTE (3D STAIR-UTE) magnetic resonance imaging (MRI) sequence. Thirty male C57BL/6 mice, with 15 experiencing mTBI and 15 serving as sham controls, were included in this study. Behavioral tests were performed starting at 5 days post-injury to assess motor activity and anxiety-like responses followed by STAIR-UTE imaging using a pre-clinical 3T MRI scanner. Additionally, a proton density-weighted UTE sequence was scanned alongside the STAIR-UTE for quantification of myelin proton fraction (MPF). Luxol fast blue (LFB) staining was performed to evaluate myelin changes between the mTBI group and the control group. The behavioral tests indicated decreased motor activity in the center zone and increased anxiety-like response in the mTBI mice compared to sham controls. The STAIR-UTE sequence revealed significantly lower MPFs in the corpus callosum of mTBI mice (8.4 ± 0.4 % vs. 8.7 ± 0.4 %; P = 0.003), consistent with the myelin reduction observed in the LFB staining (0.77 ± 0.22 vs. 1.09 ± 0.15; P = 0.004). Our findings demonstrate that the STAIR-UTE sequence facilitates quantitative myelin imaging at 3T MRI, enabling the detection of demyelination in the white matter of the mouse brain associated with alterations in motor and anxiety domains post-LIB exposure.

Blast-induced neurotrauma (BINT) is a pressing concern for veterans and civilians exposed to explosive devices. Affected personnel may have increased risk for long-term cognitive decline and developing tauopathies including Alzheimer’s disease-related disorders (ADRD) or frontal-temporal dementia (FTD). The goal of this study was to identify the effect of BINT on molecular networks and their modulation by mutant tau in transgenic (Tg) mice overexpressing the human tau P301L mutation (rTg4510) linked to FTD or non-carriers. The primary focus was on the phosphoproteome because of the prominent role of hyperphosphorylation in neurological disorders. Discrimination learning was assessed following injury in the subsequent 6 weeks, using the automated home-cage monitoring CognitionWall platform. At 40 days post injury, label-free phosphoproteomics was used to evaluate molecular networks in the frontal cortex of mice. Utilizing a weighted peptide co-expression network analysis (WpCNA) approach, we identified phosphopeptide networks tied to associative learning and mossy-fiber pathways and those which predicted learning outcomes. Phosphorylation levels in these networks were inversely related to learning and linked to synaptic dysfunction, cognitive decline, and dementia including Atp6v1a and Itsn1. Low-intensity blast (LIB) selectively increased pSer262tau in rTg4510, a site implicated in initiating tauopathy. Additionally, individual and group level analyses identified the Arhgap33 phosphopeptide as an indicator of BINT-induced cognitive impairment predominantly in rTg4510 mice. This study unveils novel interactions between ADRD genetic susceptibility, BINT, and cognitive decline, thus identifying dysregulated pathways as targets in potential precision-medicine focused therapeutics to alleviate the disease burden among those affected by BINT.

Stroke survivors face an elevated risk of developing Alzheimer’s disease (AD), yet the biological mechanisms linking these conditions remain poorly defined. Here, we show that a stroke-induced gut microbiome is a key driver of AD-related pathology. Fecal microbiota transplantation (FMT) from stroke patients into young triple-transgenic Alzheimer’s disease (3xTg-AD) mice accelerated tau phosphorylation, increased neuroinflammation, and disrupted metabolic homeostasis in both the brain and gut, compared with FMT from healthy donors. Mice receiving stroke-derived microbiota exhibited persistent, donor-specific dysbiosis and broad metabolic reprogramming involving redox balance, nucleotide metabolism, and energy pathways in cecal contents and brain tissue. These metabolic disturbances were accompanied by widespread and region-specific transcriptional changes revealed by single-cell spatial transcriptomics, including glial activation, impaired neuron–glia communication, and dysregulation of mitochondrial, amyloid-processing and inflammatory pathways across cortical and hippocampal regions. Collectively, these findings identify post-stroke gut dysbiosis as a mechanistic contributor to heightened neurodegenerative vulnerability and AD risk, highlighting the gut–brain axis as a potentially modifiable target for preventing post-stroke dementia.

Background: Aging is a risk factor for Alzheimer’s disease and related dementias, which are associated with synaptic dysfunction and cognitive decline. Elderberry (Sambucus spp.) is rich in anthocyanins with antioxidant and anti-inflammatory properties. Docosahexaenoic acid (DHA), an essential fatty acid, plays a key role in neuronal membrane integrity during brain aging. However, it remains unclear whether elderberry and DHA exert overlapping or distinct effects on brain aging and how these relate to molecular signaling. This study aimed to characterize molecular signatures induced by dietary supplementation and to determine their relationships with behavioral outcomes. Methods: 44-week-old male C57BL/6J mice were randomly assigned to control, elderberry, DHA, or combined diets for 12 weeks. Behavioral testing assessed anxiety-like behavior, spatial learning and memory. Brain tissues underwent proteomic and phosphoproteomic profiling and fatty-acid analysis. Data were analyzed using Ingenuity Pathway Analysis to identify enriched pathways, upstream regulators, and functional associations. Results: Elderberry as well as DHA supplementation induced targeted remodeling of the proteome and phosphoproteome, with pathway enrichment involving synaptogenesis, glutamatergic signaling, and long-term potentiation. Upstream-regulator analysis predicted elderberry-associated CDK5 signaling, accompanied by reduced MAPT/Tau phosphorylation at selected sites, whereas DHA supplementation was associated with CAMK-related signaling. DHA supplementation altered fatty-acid composition, increasing the n-3/n-6 ratio. Elderberry reduced anxiety-like behavior and improved target-directed search during the Barnes maze probe test. Molecular signatures were examined in relation to the measured behavioral outcomes. Conclusions: Elderberry and DHA are associated with distinct molecular networks related to synaptic function and behavioral outcomes in the aging male mouse brain. These findings support further investigation of elderberry and DHA as dietary interventions targeting molecular and behavioral features of brain aging.