Biology subjects

Morganti, J.

Publications and source records attributed to Morganti, J..

4 recordsLinked to original sources

bioRxiv2026

Anti-amyloid immunotherapy drives APOE4 specific increases in glial reactivity, perivascular immune activation, and ARIA-like events

Anti-amyloid antibodies represent the first disease modifying therapeutics for Alzheimers disease (AD). Adoption of these novel treatments has been slowed by the occurrence of amyloid related imaging abnormalities (ARIA) - treatment-associated edema (ARIA-E) or microhemorrhages (ARIA-H) that disproportionately affect carriers of the E4 allele of apolipoprotein E (APOE). With E4 carriers comprising nearly 70% of the AD population, there is a critical need to understand the unique vulnerability of E4 carriers to these events. To address this gap, we utilized the EFAD mouse model - which expresses human APOE isoforms on the 5xFAD background of amyloidosis - to directly compare the effects of anti-amyloid therapy across APOE genotypes. 9-month-old E2, E3, and E4FAD mice received weekly injections of chimeric Aducanumab (chAdu) or IgG control for 12 weeks, to assess APOE isoform-specific effects on amyloid dynamics, ARIA-H-like microhemorrhages, and underlying cellular and transcriptomic responses. E4FAD mice demonstrated plaque reductions with accompanying increases in microhemorrhages (measured on both MRI and histology), and increases in microglial and astrocyte reactivity - especially in the perivascular compartment. Additionally, vascular branching analysis and parallel single cell and spatial transcriptomics revealed a loss of vascular plasticity and increased inflammatory and immune signaling in the neurovascular units of E4FAD mice. Together, these findings suggest the cerebrovasculature of E4s is uniquely susceptible to antibody mediated vascular damage and provide immunological targets for the assessment or mitigation of ARIA risk in this highest need population

neuroscience↗

bioRxiv2026

Astrocytic response to traumatic brain injury to rescue neuronal mitochondrial dysfunction through mitochondrial transfer

As highly dynamic organelles, mitochondria play an essential role in neuronal survival and synaptic function. Excitotoxicity is as a critical factor that promotes mitochondrial dysfunction after traumatic brain injury (TBI). Intercellular mitochondrial transfer and exogenous mitochondrial transplantation are emerging concepts to understand mitochondrial trafficking in response to mitochondrial dysfunction; however, robust in vivo evidence remains limited on the extent of these processes in the central nervous system (CNS). There is a significant knowledge gap in our understanding of mitochondrial transfer mechanisms under both normal physiological conditions and after experimental TBI. Mouse lines expressing mitochondrial green-fluorescent dendra-2 (mtD2) and GFP (mtGFP) targeted to inner and outer mitochondrial membranes, respectively, were used to study astrocyte-specific (Aldh1l1-CreER; mtD2f/f - AmtD2 and Aldh1l1-CreER; mtGFPf/f - AmtGFP) and neuron-specific (CamK2aCre; mtD2f/f - NmtD2 and CamK2aCre; mtGFPf/f - NmtGFP) mitochondrial dynamics and bioenergetics in acute TBI and excitotoxicity. At 24 hrs following TBI, neurons in the NmtD2 mouse brain exhibited rapid and significant alterations in mitochondrial morphology, including changes in total mitochondrial volume, volume distribution, and sphericity. Synaptic neuronal (SN) mitochondria display robust deficits in mitochondrial bioenergetics and complex protein levels while non-synaptic neuronal (NSN) mitochondria show State III bioenergetics and complex proteins at control levels. These findings are accompanied by a marked increase in astrocyte-derived mitochondria (AmtGFP) transfer to neurons at 24 hrs post-injury, compared to control animals, but no increase in transfer to neuronal synapses. While TBI also altered astrocytic mitochondrial morphology in the cortex, astrocytic mitochondrial bioenergetics remained preserved. Single-cell RNA-seq analysis of astrocytes revealed significant transcriptional reprogramming following TBI, characterized by the upregulation of genes associated with mitochondrial homeostasis and the machinery for organelle trafficking. In vitro co-cultures of primary cortical astrocytes and neurons demonstrated that astrocytes can transfer mitochondria to neurons via direct contact and that NMDA-mediated excitotoxicity further enhanced this astrocyte-to-neuron mitochondrial transfer. Furthermore, astrocytic-derived extracellular vesicles containing mitochondria (EV-mito) deliver mitochondria to neurons and EV-mediated mitochondrial transfer significantly ameliorated NMDA-induced mitochondrial dysfunction in primary cortical neurons. Together, these findings show that astrocytes take on a TBI-related phenotype that facilitates dynamic changes in mitochondrial networks and mitochondrial trafficking to neurons. Astrocytic transfer of respiratory-competent mitochondria support is an intrinsic neuroprotective response to injury that supports mitochondrial function in neuronal soma, dendrites, and axons but not at the neuronal synapse. Finally, we show therapeutic potential of exogenous mitochondrial transfer, particularly via EV-mito, for treating neurological disorders associated with excitotoxicity, such as TBI.

neuroscience↗

bioRxiv2025

High-Resolution Spatial Profiling of Microglia Reveals Proximity Associated Immunometabolic Reprogramming in Alzheimers Disease

Single-cell RNA sequencing has demonstrated that the presence of parenchymal amyloid plaques and intracellular hyperphosphorylated tau pathology is associated with distinctive (and possibly disease-driving) microglial heterogeneity. However, our understanding of how proximity to these Alzheimers disease (AD) pathological hallmarks in situ relates to microglial gene expression remains obscure. Here, we utilized high-resolution spatial transcriptomics (ST) via the Xenium platform with a fully customized gene panel to elucidate disease-associated microglial subtypes in tandem with examining metabolic signatures across AD-relevant mouse models and well-characterized human postmortem tissue. Three mouse models were evaluated: PS19, APP/PS1, and 5xFAD. Analyzing anatomical features across entire hemisections, our approach resolved the distribution of five disease-associated microglial subtypes, while deciphering how proximity to cerebral amyloid plaques influenced transcriptional mediators governing metabolic pathways. We observed robust alterations in glycolytic and cholesterol/lipid processing pathways in plaque-associated microglia, consistent with a specific switch to glycolysis and lipid-fueled metabolism in the plaque niche. Extending our analysis to human postmortem dorsolateral prefrontal cortex (dlPFC), we identified conserved disease-reactive microglial states, i.e., similar proximity-dependent metabolic shifts around amyloid plaques. Further, integrating spatial transcriptomics with machine-learning approaches revealed novel anatomic domain-specific cellular gene expression profiling features, highlighting differential vulnerabilities of neuronal, glial, and vascular populations near specific microglial subtypes. Together, our findings provide one of the first comprehensive and high-resolution atlas of microglial immunometabolic states across species, anatomical regions, and AD pathological burden.

neuroscience↗

bioRxiv2023

ApoE4 drives maladaptive heterogeneity and immunometabolic responses of astrocytes

Apolipoprotein E4 (APOE4) is the strongest risk allele associated with the development of late onset Alzheimers disease (AD). Across the CNS, astrocytes are the predominant expressor of APOE while also being critical mediators of neuroinflammation and cerebral metabolism. APOE4 has been consistently linked with dysfunctional inflammation and metabolic processes, yet insights into the molecular constituents driving these responses remain unclear. Utilizing complementary approaches across humanized APOE mice and isogenic human iPSC astrocytes, we demonstrate that ApoE4 alters the astrocyte immunometabolic response to pro-inflammatory stimuli. Our findings show that ApoE4-expressing astrocytes acquire distinct transcriptional repertoires at single-cell and spatially-resolved domains, which are driven in-part by preferential utilization of the cRel transcription factor. Further, inhibiting cRel translocation in ApoE4 astrocytes abrogates inflammatory-induced glycolytic shifts and in tandem mitigates production of multiple pro-inflammatory cytokines. Altogether, our findings elucidate novel cellular underpinnings by which ApoE4 drives maladaptive immunometabolic responses of astrocytes.

neuroscience↗