Individuals with Down syndrome (DS) exhibit Alzheimer’s disease (AD) pathology at a young age, including amyloid plaques and neurofibrillary tangles (NFTs). Tau pathology can spread via extracellular vesicles, such as exosomes. The cargo of neuron-derived small extracellular vesicles (NDEVs) from individuals with DS contains p-Tau at an early age. The goal of the study was to investigate whether NDEVs isolated from the blood of individuals with DS can spread Tau pathology in the brain of wildtype mice. We purified NDEVs from the plasma of patients with DS-AD and controls and injected small quantities using stereotaxic surgery into the dorsal hippocampus of adult wildtype mice. Seeding competent Tau conformers were amplified in vitro from DS-AD NDEVs but not NDEVs from controls. One month or 4 months post-injection, we examined Tau pathology in mouse brains. We found abundant p-Tau immunostaining in the hippocampus of the mice injected with DS-AD NDEVs compared to injections of age-matched control NDEVs. Double labeling with neuronal and glial markers showed that p-Tau staining was largely found in neurons and, to a lesser extent, in glial cells and that p-Tau immunostaining was spreading along the corpus callosum and the medio-lateral axis of the hippocampus. These studies demonstrate that NDEVs from DS-AD patients exhibit Tau seeding capacity and give rise to tangle-like intracellular inclusions.

Synucleinopathies is an umbrella term for multiple neurological disorders, including Parkinson’s disease (PD), Lewy body dementia (LBD), and multiple system atrophy (MSA). A central pathological hallmark of synucleinopathies is the aggregation of α-synuclein (αS, a neuronal protein) and its prion-like spread. Therefore, inhibition of αS aggregation and spread is considered a viable therapeutic approach for the treatment of synucleinopathies. Foldamers are synthetic ligands that mimic the secondary structure of proteins. Using an oligoquinoline (OQ) scaffold–based foldamer approach, we have previously identified a foldamer (SK-129) that potently inhibits αS aggregation. Here, using a wide range of biophysical, cellular, and in vivo methods, we showed that SK-129 rescued synucleinopathy phenotypes in cellular, Caenorhabditis elegans , and human induced pluripotent stem cell (iPSC)–derived neuron models. SK-129 specifically bound to neurotoxic αS oligomers with ~6-fold higher affinity ( K _d = 221 ± 29 nM) than to physiological αS monomer, validating αS oligomers as a therapeutic target. Furthermore, SK-129 efficiently crossed the blood-brain barrier (BBB) and exhibited favorable pharmaceutical properties in mice. Treatment with SK-129 prevented brain histopathology and increased survival in a mouse model expressing human A53T mutant αS without showing any apparent cytotoxicity. SK-129 inhibited αS aggregation mediated by exosomes derived from C. elegans or patients with PD in HEK293T reporter cells. SK-129 completely inhibited the coaggregation of αS-tau, a pathological biomarker for LBD in both cellular and mouse models. Overall, we report a potent foldamer with therapeutic potential for PD and LBD.

An understanding of the immune mechanisms that lead to rejection versus tolerance of allogeneic pancreatic islet grafts is of paramount importance, as it facilitates the development of innovative methods to improve the transplant outcome. Here, we used our established intraocular islet transplant model to gain novel insight into changes in the local metabolome and proteome within the islet allograft’s immediate microenvironment in association with immune-mediated rejection or tolerance. We performed integrated metabolomics and proteomics analyses in aqueous humor samples representative of the graft’s microenvironment under each transplant outcome. The results showed that several free amino acids, small primary amines, and soluble proteins related to the Warburg effect were upregulated or downregulated in association with either outcome. In general, the observed shifts in the local metabolite and protein profiles in association with rejection were consistent with established pro-inflammatory metabolic pathways and those observed in association with tolerance were immune regulatory. Taken together, the current findings further support the potential of metabolic reprogramming of immune cells towards immune regulation through targeted pharmacological and dietary interventions against specific metabolic pathways that promote the Warburg effect to prevent the rejection of transplanted islets and promote their immune tolerance.

Longevity science has shifted from the pursuit of lifespan extension toward preservation of healthspan, resilience, and functional independence. The hallmarks of aging provide a powerful descriptive structure, but they do not by themselves specify how diverse molecular defects translate into loss of adaptive function. We propose a complementary conceptual framework in which aging is viewed as progressive impairment of biological self-correction: the distributed capacity to sense consequential perturbations, scale an appropriate response, repair or remove damage, terminate the response, and recover or adaptively re-equilibrate while preserving future functional reserve. This framework is not intended to replace homeostasis, homeodynamics, allostasis, physiological reserve, or resilience; rather, it links these established concepts to the molecular machinery that generates dynamic recovery. Correction fidelity is proposed to be measured independently of the hallmarks using stress-response trajectories, including response latency, magnitude of deviation, recovery slope or half-time, integrated deviation, residual deficit, overshoot, biological cost, final functional state, and preservation of subsequent reserve. Importantly, successful recovery need not mean return to a fixed youthful baseline because aging may also shift the physiological setpoint toward a less favorable but actively defended equilibrium. We integrate evolutionary and biodemographic principles with inflammaging, nutrient sensing, NAD+ biology, senescence, autophagy, partial reprogramming, and resilience research, and propose falsifiable predictions for testing whether dynamic recovery adds information beyond chronological age, frailty, and static aging biomarkers.