Citations

AbstractBackgroundAlzheimer’s Disease (AD) has no cure. We showed that partial inhibition of mitochondrial complex I (MCI) with small molecule CP2 induced adaptive stress response activating multiple neuroprotective mechanisms. Chronic treatment reduced inflammation, improved synaptic and mitochondrial functions, and blocked neurodegeneration in symptomatic APP/PS1 mice, a translational model of AD.MethodsAnalysis of mitochondrial morphology and mitochondria‐endoplasmic reticulum (ER) contacts (MERCS) was done in the hippocampal CA1 tissue from APP/PS1 mice treated with CP2 and compared to APP/PS1 and non‐transgenic mice treated with vehicle using serial block‐face scanning electron microscopy (SBFSEM) and three‐dimensional (3D) EM reconstructions combined with western blot analysis and next generation RNA sequencing.ResultsWe demonstrate that CP2 treatment restores mitochondrial morphology and mitochondria‐ ER communication, reducing ER stress in the APP/PS1 mouse brain. Using 3D EM reconstructions, we found that mitochondria in AD dendrites existed primarily as mitochondria‐on‐a‐string (MOAS), a morphological phenotype that is difficult to detect using conventional 2D EM or fluorescence spectroscopy. Compared to other morphological phenotypes, MOAS are extensively enveloped in the ER membranes forming multiple MERCS known to contribute to abnormal lipid and calcium homeostasis, and ER stress in AD. CP2 treatment specifically reduced MOAS formation, consistent with improved energy homeostasis in the brain, with concomitant reduction in MERCS, ER stress, and improved lipid homeostasis.ConclusionsThese data provide novel information on the role MOAS play in AD. Our data demonstrate that in response to energetic stress, mitochondria in dendrites acquire MOAS phenotype with increased interaction with the ER, which may synergistically contribute to the AD development. Since CP2 treatment alleviated the ER stress and improved mitochondrial dynamics and function, these data further support the development of partial MCI inhibitors as disease modifying strategy for AD.

AbstractBackgroundGlial activation plays a critical role in Alzheimer’s disease (AD) pathogenesis and is associated with amyloid‐β plaques and neurofibrillary tangles composed of phosphorylated tau (phospho‐tau). With approximately 40%‐60% of AD cases having limbic‐predominant age‐related TDP‐43 encephalopathy neuropathologic change (LATE‐NC), TDP‐43 pathology has become more the rule than the exception in AD brains. However, the effect of LATE‐NC in AD‐related glial activation is unknown.MethodWe analyzed the effect of TDP‐43 pathology on glial activation in three AD subtypes: hippocampal sparing (HpSp) AD, typical AD, and limbic predominant AD. Twenty cases of each subtype (n = 60 total) were selected from the FLorida Autopsied Multi‐Ethnic (FLAME) cohort. Cases were immunohistochemically evaluated on serial sections of the hippocampus in the CA1 and subiculum subsectors, and superior temporal, inferior parietal, and mid‐frontal cortices with antibodies to CD68 (phagocytosis), GFAP (astrogliosis), GT‐38 (conformation‐specific AD‐type tau), 6F/3D (amyloid‐β), and phospho‐Serine 409/410 of TDP‐43 (pTDP‐43). Digital pathology was employed to quantify immunohistochemical staining. Multivariable regression modeling was utilized to understand the relationship between glial activation and AD pathologies.ResultThe level of glial activation, defined as % of immunoreactive surface area for CD68 and GFAP, was lowest in HpSp AD (0.54%, 13%), whereas typical AD (1.3%, 33%) and limbic predominant AD (1.3%, 30%) had similar levels suggesting a ceiling effect, or plateau, of gliosis levels (both p<0.001). HpSp AD was more often male (p<0.001) and younger at disease onset (p<0.001) compared to both typical AD and limbic predominant AD. Multivariable regression modeling of CD68 (subiculum R2 = 0.60) identified advanced tau to be a significant predictor of CD68 in all brain regions. LATE‐NC stage predicted increased CD68 levels in limbic brain regions. Multivariable regression modeling of GFAP (CA1 R2 = 0.60) showed that Aβ was the strongest predictor of astrogliosis in CA1 and subiculum (p<0.001). Advanced tau in CA1 and parietal cortex, LATE‐NC in subiculum and temporal cortex, and APOE4 genotype in CA1 predicted a significant increase in GFAP.ConclusionThese findings highlight the significant role TDP‐43 pathology plays in affecting the microenvironment and interplay between neuroinflammation and neurodegeneration and have important implications for therapeutic strategies in AD with co‐morbid LATE‐NC.

AbstractBackgroundTau proteins aggregate into spatially and morphologically distinct lesions in primary and secondary tauopathies. These signature lesions result from deposition of tau proteins that are distinctly modified via missense mutation and/or post‐translational modification for each disease strain. Identifying the unique tau protein abnormalities that lead to specific neurodegenerative diseases is beneficial in their early diagnosis and treatment. This is especially true for Progressive Supranuclear Palsy a primary tauopathy with clinical symptoms mirroring Parkinsonian syndromes and frontotemporal dementias.MethodBiochemical analysis of tau aggregates from patients with a pathological diagnosis of Progressive Supranuclear Palsy (n = 60) demonstrate that the tau protein modifications observed in this disease result from tau that is specifically modified and thereby forms the basis of the distinct disease strains observed. Here data collected using the sarkosyl‐insoluble tau fractions from tissue samples of pathologically diagnosed patients with Progressive Supranuclear Palsy without comorbidities allows for the direct observation of the modifications. Most interesting is the variability of the tau proteins that actually accumulate for this disease opening up the possibility that tau strains may exist within any given tauopathy even as the clinical manifestations appear similar. This indicates that early and specific identification and detection of these strains is critical for the development of therapies for these diseases.ResultExtraction and examination of sarkosyl‐insoluble tau proteins from deceased patients pathologically diagnosed with Progressive Supranuclear Palsy indicate that multiple tau strains exist within this primary tauopathy. Western blotting of these extracts from patient tissues demonstrates a unique banding pattern of insoluble tau in a subset of the cases that exhibit extreme hyperphosphorylation as indicated by additional high molecular weight tau banding. These patients also had an earlier age of onset and age of death indicating a more aggressive disease strain. Additional data is presented comparing the structure and seeding capability of this insoluble tau and the distribution and burden of insoluble tau in these Progressive Supranuclear Palsy patients compared to those with typical onset and insoluble tau signature.ConclusionMultiple pathological tau strains exist in Progressive Supranuclear Palsy.

AbstractBackgroundContext‐specific networks can capture functionally important genes that may not be differentially expressed. Leveraging seven different gene expression datasets of Alzheimer’s disease (AD) and healthy control brains, we constructed a novel pipeline that includes such network analysis, augmented by in vivo validations and in silico drug repurposing to facilitate prioritization of AD therapeutic targets.MethodWe utilized publicly available gene expression data from 733 AD and 454 control brains across 7 datasets and the NetDecoder (PMID: 26975659) network biology platform to build context‐specific networks. Based on the known protein‐protein interaction and gene expression correlations, information flow from the top differentially expressed genes (DEG) to transcriptional regulator genes was calculated using a process‐guided flow algorithm. Genes with the greatest informational flow changes across AD cohorts were systematically prioritized. We next validated these genes in a medium‐throughput screen of a tau‐transgenic Drosophila model (PMID: 11408621). Further, we identified existing small‐molecule drugs to target the candidate genes utilizing curated databases.ResultsA total of 14 context‐specific networks were constructed across 7 datasets. We found AD‐related genes, such as APP, to have high flow differences between AD and control networks and high connectivity. Notably, many such genes were not DEGs between AD and control, suggesting that the information flow captures novel aspects of AD pathophysiology. We nominated 224 unique genes with the greatest flow differences for functional validation. We screened 111 of the 224 candidate genes with readily available, high‐confidence orthologs in Drosophila. We identified genes that suppress (N = 68) or enhance (N = 27) tau‐related neurodegeneration in this model. We confirmed the effects of previously nominated genes, such as HDAC1, which enhances tau‐neurodegeneration if overexpressed and suppresses it if knocked down. We also identified and validated additional therapeutic targets. Lastly, we applied a network‐proximity‐based algorithm and identified small molecule drugs for the candidate genes.ConclusionWe present a novel pipeline that integrates analytic approaches, experimental validation, and drug repurposing to facilitate therapeutic discovery in AD. We applied this pipeline and nominated previously known and novel genes implicated in AD pathogenesis. Our pipeline demonstrates a cross‐species, systems‐level approach to therapeutic nomination in AD and related neurodegenerative diseases.

AbstractBackgroundThe coarse‐grained plaque is a biochemically and morphologically distinct amyloid‐β (Aβ) deposit that was discovered in clinically‐defined atypical Alzheimer’s disease (AD). Unlike other Aβ deposits, this plaque is not observed in cognitively normal people. This study investigates the hypothesis that the coarse‐grained plaque is distinctly associated with AD neuropathologic change and glial activation within the context of AD subtypes.MethodSixty AD cases from the FLorida Autopsied Multi‐Ethnic (FLAME) cohort were assessed. We included 20 hippocampal sparing (HpSp) AD, 20 typical AD, and 20 limbic predominant AD. Immunohistochemistry was performed on the middle frontal, inferior temporal, and inferior parietal cortex for AD neuropathology (Aβ [6F/3D], phospho‐tau [AT8], tau [GT38]) and glial activation (CD68 [KP1] and GFAP). Digital pathology was used to quantify burden. Thioflavin‐S tangle counts were performed at time of neuropathologic diagnosis. Distinct deposit types, including classic cored plaques, coarse‐grained plaques, cerebral amyloid angiopathy (CAA)‐Type 1, and CAA‐Type 2, were semi‐quantitatively scored on Aβ (Fig. 1). Correlations between demographic, clinical, and neuropathologic characteristics were assessed using Spearman rho analysis and reported if p<0.05. An independent cohort of ∼100 HpSp AD cases will be assessed to validate initial findings.ResultIn the frontal cortex of HpSp AD, higher scores of classic cored plaques correlated with older age at onset and death, non‐APOE ε4 carriership, and less CAA‐Type 1 and Type 2 (Fig. 2). On the contrary, the severity of coarse‐grained plaques correlated with a younger age at onset and death, APOE ε4 carriership, higher scores for CAA‐Type 1, CAA‐Type 2, and increased burden of Aβ, GFAP, and CD68. Classic cored plaques correlated negatively with phospho‐tau and tau, whereas coarse‐grained plaques correlated positively with phospho‐tau, tau, and tangles. The two deposit types were negatively correlated with each other. Correlations were weaker but showed similar trends in other AD subtypes (Fig. 2) and regions.ConclusionWithin HpSp AD, classic cored and coarse‐grained plaques show distinct correlations with glial activation, (phospho‐)tau, and tangles. These results suggest opposite directions of association for these deposits on AD neuropathologic change that may impact clinical symptoms. These findings are relevant to therapies targeting overall Aβ pathology.

Abstract Background Myocarditis is an inflammation of the heart muscle most often caused by an immune response to viral infections. Sex differences in the immune response during myocarditis have been well described but upstream mechanisms in the heart that might influence sex differences in disease are not completely understood. Methods Male and female BALB/c wild type mice received an intraperitoneal injection of heart-passaged coxsackievirus B3 (CVB3) or vehicle control. Bulk-tissue RNA-sequencing was conducted to better understand sex differences in CVB3 myocarditis. We performed enrichment analysis to understand sex differences in the transcriptional landscape of myocarditis and identify candidate transcription factors that might drive sex differences in myocarditis. Results The hearts of male and female mice with myocarditis were significantly enriched for pathways related to an innate and adaptive immune response compared to uninfected controls. When comparing females to males with myocarditis, males were enriched for inflammatory pathways and gene changes that suggested worse mitochondrial transcriptional support (e.g., mitochondrial electron transport genes). In contrast, females were enriched for pathways related to mitochondrial respiration and bioenergetics, which were confirmed by higher transcript levels of master regulators of mitochondrial function including peroxisome proliferator-activated receptor gamma coactivator 1 (PGC1α), nuclear respiratory factor 1 (NRF1) and estrogen-related receptor alpha (ERRα). TRANSFAC analysis identified ERRa as a transcription factor that may mediate sex differences in mitochondrial function during myocarditis. Conclusions Master regulators of mitochondrial function were elevated in females with myocarditis compared to males and may promote sex differences in mitochondrial respiratory transcript expression during viral myocarditis resulting in less severe myocarditis in females following viral infection.

Introduction: Patients with coronary artery disease (CAD) are at increased risk of cognitive decline. A proposed mechanism is cerebral hypoperfusion related to vascular dysfunction and impaired cerebral blood flow regulation Hypothesis: Patients with CAD will have lower cerebrovascular function than age- and sex-matched controls, assessed as reactivity to a vasodilatory carbon dioxide (CO 2 ) stimulus. Methods: Adults 40-70years old with CAD were recruited on enrollment to a cardiac rehabilitation program following a cardiac event or hospitalization. Age and sex-matched adults without known disease or cardiovascular risk factors were recruited as healthy controls. Cognitive function was assessed by the Fluid Composite of the NIH Cognition Toolbox. Following a familiarization visit, participants underwent a stepped CO 2 protocol (room air, 2% CO 2 , 4% CO 2 , 6% CO 2 ) while continuously measuring middle cerebral artery velocity (MCAv) using transcranial doppler ultrasound, mean arterial pressure (MAP), ventilation (VE), and end-tidal CO 2 . Cerebrovascular conductance (CVCi) was calculated as MCAv/MAP. Cerebrovascular reactivity was calculated as the linear regression slope of CVCi against the change in end-tidal CO 2 . The reactivity of MAP and VE (or chemosensitivity) were also calculated. Results: 19 patients with CAD and 10 healthy controls were recruited ( Table 1 ). Compared with controls, patients with CAD had a 2-fold lower cerebrovascular reactivity (p=0.003), higher MAP reactivity (p<0.05), and a trend towards higher chemosensitivity (p<0.1) ( Table 2 ). There were no group differences in resting CVCi or cognition ( Table 2 ). After adjustment for age and sex, lower cerebrovascular reactivity was associated with lower peak oxygen uptake, diabetes, and smoking history ( Table 3 ). Conclusions: Compared with healthy controls, we report that patients with CAD have significantly lower cerebrovascular function, with no differences in cognitive function.

AbstractBackgroundWe sought to characterize and compare late patient‐reported outcomes (PROs) after moderately hypofractionated intensity modulated radiation therapy (IMRT) and proton beam therapy (PBT) for localized prostate cancer (PC).MethodsThis multi‐institutional analysis included low‐ or intermediate‐risk group PC patients treated with moderately hypofractionated radiation to an intact prostate stratified by treatment modality: IMRT or PBT. The primary outcomes were prospectively collected patient‐reported late gastrointestinal (GI) and genitourinary (GU) toxicity assessed by International Prostate Symptom Score (IPSS) and Expanded PC Index Composite (EPIC). Multivariable regression analysis (MVA) controlling for age, race, and risk group tested the effect of time, treatment, and their interaction.Results287 IMRT and 485 PBT patients were included. Intermediate risk group (81.2 vs. 68.2%; p < 0.001) and median age at diagnosis (70 vs. 67 years; p < 0.001) were higher in the IMRT group. On MVA, there was no significant difference between modalities. PBT IPSS did not differ from IMRT IPSS at 12 months (odds ratio [OR], 1.19; p = 0.08) or 24 months (OR, 0.99; p = 0.94). PBT EPIC overall GI function at 12 months (OR, 3.68; p = 0.085) and 24 months (OR 2.78; p = 0.26) did not differ from IMRT EPIC overall GI function. At 24 months, urinary frequency was no different between PBT and IMRT groups (OR 0.35; p = 0.096).ConclusionsThis multi‐institutional analysis of low‐ or intermediate‐risk PC treated with moderately hypofractionated PBT and IMRT demonstrated low rates of late patient‐reported GI and GU toxicities. After covariate adjustment, late GI and GU PROs were not significantly different between PBT or IMRT cohorts.

BACKGROUND AND OBJECTIVES: Anecdotal cases of rapidly progressing dementia in patients with dural arteriovenous fistulas (dAVFs) have been reported in small series. However, large series have not characterized these dAVFs. We conducted an analysis of the largest cohort of dAVFs presenting with cognitive impairment (dAVFs-CI), aiming to provide a detailed characterization of this subset of dAVFs. METHODS: Patients with dAVFs-CI were analyzed from the CONDOR Consortium, a multicenter repository comprising 1077 dAVFs. A propensity score matching analysis was conducted to compare dAVFs-CI with Borden type II and type III dAVFs without cognitive impairment (controls). Logistic regression was used to identify angiographic characteristics specific to dAVFs-CI. Furthermore, post-treatment outcomes were analyzed. RESULTS: A total of 60 patients with dAVFs-CI and 60 control dAVFs were included. Outflow obstruction leading to venous hypertension was observed in all dAVFs-CI. Sinus stenosis was significantly associated with dAVFs-CI (OR 2.85, 95% CI: 1.16-7.55, P = .027). dAVFs-CI were more likely to have a higher number of arterial feeders (OR 1.56, 95% CI 1.22-2.05, P < .001) and draining veins (OR 2.05, 95% CI 1.05-4.46, P = .004). Venous ectasia increased the risk of dAVFs-CI (OR 2.38, 95% CI 1.13-5.11, P = .024). A trend toward achieving asymptomatic status at follow-up was observed in patients with successful closure of dAVFs (OR 2.86, 95% CI 0.85-9.56, P = .09) CONCLUSION: Venous hypertension is a key angiographic feature of dAVFs-CI. Moreover, these fistulas present at a mean age of 58 years-old, and exhibit a complex angioarchitecture characterized by an increased number of arteriovenous connections and stenosed sinuses. The presence of venous ectasia further exacerbates the impaired drainage and contributes to the development of dAVFs-CI. Notably, in certain cases, closure of the dAVF has the potential to reverse symptoms.