👤 James Schilling

Individuals with Alzheimer's disease (AD) are at an increased risk of bone fracture, while osteoporosis in women is one of the earliest predictors of AD. Yet the mechanisms linking cognitive decline and skeletal deterioration remain poorly defined. Proteomic analysis of cortical bone from aged 21-month-old mice revealed strong enrichment of neurodegeneration-associated proteins, including apolipoprotein E (Apoe) and amyloid precursor protein. Apoe localized specifically to osteocytes, with expression in aged female bone nearly twice that of young 4-month-old male bone. Because human APOE alleles confer different age-related AD risks, we examined their roles in bone using humanized APOE2, APOE3, and APOE4 knock-in mice and analyzed bone and hippocampus from the same animals. APOE4 produced marked sex-specific effects on the bone transcriptome and proteome compared with APOE2 or APOE3. Strikingly, APOE4-associated proteomic disruptions were stronger in female bone than in the hippocampus. Functionally, APOE4 caused bone fragility in females without altering cortical structure. These deficits stemmed from impaired osteocyte perilacunocanalicular remodeling. Our findings identify APOE4 as a molecular driver of early osteocyte dysfunction and reduced bone quality, disproportionately affecting females. These findings highlight osteocytes as potential targets for early diagnosis of age-related cognitive impairment and treatment for bone fragility, in females. Show less

Anti-amyloid antibody treatment for Alzheimer's disease is linked to Amyloid-Related Imaging Abnormalities (ARIA), including vasogenic edema (ARIA-E) and microhemorrhages (ARIA-H), especially in ApoE ε4/4 carriers. To investigate mechanisms underlying ARIA, we examined the binding and temporal vascular effects of immunization with 3D6, the precursor to the anti-amyloid antibody bapineuzumab, in two aged Alzheimer's disease amyloid mouse models. Acutely, 3D6 bound to cerebral amyloid angiopathy (CAA), resulting in C1q binding and classical complement activation. Weekly short-term immunization over 7 weeks resulted in elevated CAA- and plaque-associated complement deposition, red blood cell extravasation and microhemorrhages, and was accompanied by significant transcriptomic changes in genes related to complement, inflammation, vascular dysfunction, and endothelial lipid responses. Longer-term dosing over 13-15 weeks further increased complement deposition and was associated with blood-brain barrier disruption, MMP-9 upregulation, and microhemorrhages, accompanied by reduced amyloid burden and modest CAA clearance. C3 levels correlated with microhemorrhage severity. Perivascular macrophages co-localized with complement-decorated CAA in 3D6-treated mice. These findings implicate complement activation as an early key driver of ARIA and suggest that therapeutic targeting of complement may reduce ARIA risk. Show less

Lipofilling is a widely used technique in plastic and reconstructive surgery, but its long-term success is often limited by unpredictable fat graft resorption. Optimizing the adipogenic environment through bioactive factors may enhance graft survival and volume retention. This study investigates the adipogenic potential of Hypoxia Preconditioned Serum (HPS) and Platelet-rich Plasma (PRP), in comparison to normal serum (NS). Cytokine profiles of HPS, PRP, and NS from 10 donors were analyzed. Human preadipocytes (n = 3) were cultured with low (10%) and high (40%) concentrations of these secretomes. Proliferation, cytotoxicity (LDH assay), lipid droplet formation (Oil Red O staining), and gene expression (qPCR) of adipogenic markers (PPARgamma, C/EBPalpha, FABP4, Adiponectin, LPL) were assessed after 2 and 4 days. HPS contained significantly higher levels of Adiponectin, IGF-1, bFGF, VEGF-A, and PDGF-BB compared with PRP and NS, while Leptin was lower in HPS and PRP than in NS. All conditions increased proliferation on day 4, with the highest cell counts in NS-40%. No treatment-related cytotoxicity was observed. HPS-40% induced the strongest adipogenic differentiation, evidenced by increased lipid droplet formation and upregulation of all measured adipogenic genes by day 4. These findings suggest that HPS enhance the proliferation, survival, and differentiation of preadipocytes. Validation in Show less

The study examined the association between body composition and beverage consumption and the risk of asthma and chronic obstructive pulmonary disease (COPD) and explored the single nucleotide polymorphisms (SNPs) involved in these associations by leveraging summary statistics from genome-wide association studies (GWAS) in nonoverlapping populations. The IEU OpenGWAS project was sourced for exposure datasets: body mass index, body fat percentage, fat-free mass, total body water mass, alcohol intake frequency, and coffee intake, and selected health outcome datasets: asthma and chronic obstructive pulmonary disease. Datasets were assessed and filtered using R, followed by a two-sample Mendelian randomization analysis. The MR Egger, weighted median, inverse variance weighted, simple mode, and weighted mode methods were used to examine the association between exposures and outcomes. Heterogeneity and pleiotropy analyses were used to evaluate the reliability of results. Additionally, SNPnexus was used to ascertain SNPs linked to established phenotypes, while SNP annotation was obtained from the Ensembl BioMart database via the biomaRt package. Genes belonging to overlapping groups were visualized using ComplexHeatmap. Higher body fat percentage (OR = 1.72, 95% CI: 1.23-2.41, Show less

Primary aldosteronism (PA), a significant cause of secondary hypertension affecting ∼10% of patients with severe hypertension, exacerbates cardiovascular, and cerebrovascular complications even after blood pressure control. PA is categorized into two main subtypes: unilateral aldosterone-producing adenomas (APA) and bilateral hyperaldosteronism (BHA), each requiring distinct treatment approaches. Accurate subtype classification is crucial for selecting the most effective treatment. The goal of this study was to develop novel blood-based proteomic biomarkers to differentiate between APA and BHA subtypes in patients with PA. Five subtyping differential protein biomarker candidates (APOC3, CD56, CHGA, KRT5, and AZGP1) were identified through targeted proteomic profiling of plasma. The subtyping efficiency of these biomarkers was assessed at both the tissue gene expression and blood protein expression levels. To explore the underlying biology of APA and BHA, significant differential pathways were investigated. The five-protein panel proved highly effective in distinguishing APA from BHA in both tissue and blood samples. By integrating these five protein biomarkers with aldosterone and renin, our blood-based predictive methods achieved remarkable receiver operating characteristic (ROC) area under the ROC curves of 0.986 (95% CI: 0.963-1.000) for differentiating essential hypertension from PA, and 0.922 (95% CI: 0.846-0.998) for subtyping APA versus BHA. These outcomes surpass the performance of the existing Kobayashi score subtyping system. Furthermore, the study validated differential pathways associated with the pathophysiology of PA, aligning with current scientific knowledge and opening new avenues for advancing PA care. The new blood-based biomarkers for PA subtyping hold the potential to significantly enhance clinical utility and advance the practice of PA care. Show less

DNA methylation (DNAm) is an epigenetic mark with essential roles in disease development and predisposition. Here, we created genome-wide maps of methylation quantitative trait loci (meQTL) in three peripheral tissues and used Mendelian randomization (MR) analyses to assess the potential causal relationships between DNAm and risk for two common neurodegenerative disorders, i.e. Alzheimer's disease (AD) and Parkinson's disease (PD). Genome-wide single nucleotide polymorphism (SNP; ~5.5M sites) and DNAm (~850K CpG sites) data were generated from whole blood (n=1,058), buccal (n=1,527) and saliva (n=837) specimens. We identified between 11 and 15 million genome-wide significant (p<10 Show less

PSENEN/PEN2 is the smallest subunit of the γ-secretase complex, an intramembrane protease that cleaves proteins within their transmembrane domains. Mutations in components of the γ-secretase underlie familial Alzheimer disease. In addition to its proteolytic activity, supplementary, γ-secretase independent, functions in the macroautophagy/autophagy-lysosome system have been proposed. Here, we screened for PSENEN-interacting proteins and identified CLN3. Mutations in Show less

Adipocytes transfer mitochondria to macrophages in white and brown adipose tissues to maintain metabolic homeostasis. In obesity, adipocyte-to-macrophage mitochondria transfer is impaired, and instead, adipocytes release mitochondria into the blood to induce a protective antioxidant response in the heart. We found that adipocyte-to-macrophage mitochondria transfer in white adipose tissue is inhibited in murine obesity elicited by a lard-based high-fat diet, but not a hydrogenated-coconut-oil-based high-fat diet, aging, or a corn-starch diet. The long-chain fatty acids enriched in lard suppress mitochondria capture by macrophages, diverting adipocyte-derived mitochondria into the blood for delivery to other organs, such as the heart. The depletion of macrophages rapidly increased the number of adipocyte-derived mitochondria in the blood. These findings suggest that dietary lipids regulate mitochondria uptake by macrophages locally in white adipose tissue to determine whether adipocyte-derived mitochondria are released into systemic circulation to support the metabolic adaptation of distant organs in response to nutrient stress. Show less

Hypovitaminosis D is common in the obese population and patients suffering from obesity-associated disorders such as type 2 diabetes and fatty liver disease, resulting in suggestions for vitamin D supplementation as a potential therapeutic option. However, the pathomechanistic contribution of the vitamin D-vitamin D receptor (VDR) axis to metabolic disorders is largely unknown. We analyzed the pathophysiological role of global and intestinal VDR signaling in diet-induced obesity (DIO) using global Vdr-/- mice and mice re-expressing an intestine-specific human VDR transgene in the Vdr deficient background (Vdr-/- hTg). Vdr-/- mice were protected from DIO, hepatosteatosis and metabolic inflammation in adipose tissue and liver. Furthermore, Vdr-/- mice displayed a decreased adipose tissue lipoprotein lipase (LPL) activity and a reduced capacity to harvest triglycerides from the circulation. Intriguingly, all these phenotypes were partially reversed in Vdr-/- hTg animals. This clearly suggested an intestine-based VDR activity on systemic lipid homeostasis. Scrutinizing this hypothesis, we identified the potent LPL inhibitor angiopoietin-like 4 (Angptl4) as a novel transcriptional target of VDR. Our study suggests a VDR-mediated metabolic cross-talk between gut and adipose tissue, which significantly contributes to systemic lipid homeostasis. These results have important implications for use of the intestinal VDR as a therapeutic target for obesity and associated disorders. Show less

CLN diseases are mostly fatal lysosomal storage diseases that lead to neurodegeneration in the CNS. We have previously shown that CD8+ T-lymphocytes contribute to axonal perturbation and neuron loss in the CNS of Ppt1(-/-) mice, a model of CLN1 disease. We now investigated the role of the inflammation-related cell adhesion molecule sialoadhesin (Sn) in Ppt1(-/-) and Cln3(-/-) mice, a model of the most frequent form, CLN3 disease. Microglia/macrophages in the CNS of both models showed an upregulation of Sn and markers for proinflammatory M1 polarization and antigen presentation. Sn+ microglia/macrophages associated with SMI32+ axonal spheroids and CD8+ T-lymphocytes. To analyze their pathogenic impact, we crossbred both models with Sn-deficient mice and scored axonal degeneration and neuronal integrity using immunohistochemistry, electron microscopy and optical coherence tomography. Degenerative alterations in the retinotectal pathway of Ppt1(-/-)Sn(-/-) and Cln3(-/-)Sn(-/-) mice were significantly reduced. Ppt1(-/-)Sn(-/-) mice also showed a substantially improved clinical phenotype and extended lifespan, attenuated numbers of M1-polarized microglia/macrophages and reduced expression levels of proinflammatory cytokines. This was accompanied by an increased frequency of CD8+CD122+ T-lymphocytes in the CNS of Ppt1(-/-)Sn(-/-) mice, the regulatory phenotype of which was demonstrated by impaired survival of CD8+CD122- effector T-lymphocytes in co-culture experiments. We show for the first time that increased Sn expression on microglia/macrophages contributes to neural perturbation in two distinct models of CLN disease. Our data also indicate that a rarely described CD8+CD122+ T-cell population can regulate the corresponding diseases. These studies provide insights into CLN pathogenesis and may guide in designing immuno-regulatory treatment strategies. Show less

The same pathway, such as the mitogen-activated protein kinase (MAPK) pathway, can produce different cellular responses, depending on stimulus or cell type. We examined the phosphorylation dynamics of the MAPK kinase MEK and its targets extracellular signal-regulated kinase 1 and 2 (ERK1/2) in primary hepatocytes and the transformed keratinocyte cell line HaCaT A5 exposed to either hepatocyte growth factor or interleukin-6. By combining quantitative mass spectrometry with dynamic modeling, we elucidated network structures for the reversible threonine and tyrosine phosphorylation of ERK in both cell types. In addition to differences in the phosphorylation and dephosphorylation reactions, the HaCaT network model required two feedback mechanisms, which, as the experimental data suggested, involved the induction of the dual-specificity phosphatase DUSP6 and the scaffold paxillin. We assayed and modeled the accumulation of the double-phosphorylated and active form of ERK1/2, as well as the dynamics of the changes in the monophosphorylated forms of ERK1/2. Modeling the differences in the dynamics of the changes in the distributions of the phosphorylated forms of ERK1/2 suggested that different amounts of MEK activity triggered context-specific responses, with primary hepatocytes favoring the formation of double-phosphorylated ERK1/2 and HaCaT A5 cells that produce both the threonine-phosphorylated and the double-phosphorylated form. These differences in phosphorylation distributions explained the threshold, sensitivity, and saturation of the ERK response. We extended the findings of differential ERK phosphorylation profiles to five additional cultured cell systems and matched liver tumor and normal tissue, which revealed context-specific patterns of the various forms of phosphorylated ERK. Show less