Xuemei Zong

In Alzheimer’s disease (AD), impaired CNS lymphatic drainage may disrupt the clearance of brain-derived solutes and alter their delivery to the deep cervical lymph nodes (dCLNs), a major downstream site of CNS lymphatic outflow and a potential neuroimmune interface. However, whether the dCLN has a distinct immune profile compared with neighboring cervical lymph nodes remains unclear. Using a publicly available dataset, we reanalyzed single-cell RNA-sequencing and paired immune-receptor data from the dCLN, superficial cervical lymph node (sCLN), and inguinal lymph node (iLN) of wild-type and 5xFAD mice. Clonotype sharing reconstructed missing sample-to-animal relationships, establishing six mice as biological replicates with paired sampling across all three nodes. Analysis of 38,786 cells revealed extensive similarity between the two cervical nodes: most lymphocyte differences between the dCLN and iLN were also observed between the sCLN and iLN, indicating a shared cervical immune profile. Within this shared background, however, the dCLN showed relatively more monocytes/macrophages and fewer dendritic cells, while memory CD4 T cells exhibited a dCLN > sCLN > iLN gradient in Itga4 detection. Together, these findings suggest that the dCLN largely shares the immune landscape of neighboring cervical nodes but retains selective myeloid and T-cell features that may be related to its position within the CNS lymphatic drainage pathway and its potential involvement in AD-associated neuroimmune response.

Anti-amyloid antibodies have validated amyloid-β (Aβ) as a disease-relevant target in Alzheimer's disease (AD), but their modest clinical effect, efficacy largely restricted to early disease, and amyloid-related imaging abnormalities (ARIA) indicate that Aβ removal alone does not resolve the glial, lipid, and inflammatory programmes that sustain neurodegeneration. Microglia sit at the centre of this therapeutic gap. Single-nucleus and spatial profiling has resolved several AD-associated microglial states, yet state labels remain descriptive and do not explain why adaptive engagement becomes maladaptive. We frame AD-relevant microglial dysfunction as checkpoint collapse: progressive failure of regulatory nodes that coordinate lipid sensing, lysosomal competence, neuronal restraint, and inflammatory threshold control. The central nodes are TREM2-mediated lipid and apolipoprotein sensing, progranulin-associated lysosomal regulation, CX3CR1-dependent neuron-microglia restraint, and CD33/Siglec-3 inhibitory tone. When these controls destabilise, downstream pathology can be organised around three coupled effector axes: a lipid axis centred on APOE-biased cholesterol trafficking, ACSL1/DGAT2-driven lipid-droplet accumulation, and impaired lysosomal flux; an iron/ferroptosis axis involving labile iron, phospholipid peroxidation, and insufficient GPX4/FSP1 defences; and an inflammation/complement axis linking NLRP3 activation, type-I interferon signalling, and C1q/C3-dependent synaptic engulfment to tau pathology and synapse loss. White-matter injury, astrocyte-microglia crosstalk, and cGAS-STING-linked senescence are integrated as cross-axis amplifiers. This framework is proposed as a hypothesis-generating scaffold for biomarker-informed translational studies, rather than as a validated clinical stratification system. It may help organise stage-aware therapeutic hypotheses, including regulatory-node preservation in early disease, lipid-handling restoration and ferroptosis control at intermediate stages, and complement- or senescence-directed modulation in later disease. Current glial, iron, inflammatory, and imaging biomarkers remain insufficiently specific to assign individual patients reliably to discrete pathological axes in clinical practice.

White-matter (WM) injury contributes to disability across multiple sclerosis, traumatic brain injury, Alzheimer’s disease and related dementias, and small-vessel disease. We use microglial state programs as an organizing axis for WM injury-to-repair logic, while emphasizing that WM outcomes are multicellular and involve oligodendrocyte-lineage cells, astrocytes, axons/neurons, and vascular factors. Microglia span an injury–repair continuum, from inflammatory programs that increase oxidative stress and debris burden to repair-competent programs that support debris handling, remyelination, and axonal integrity. Near-infrared photobiomodulation (PBM; ~800–1100 nm) is most consistently associated with modulation of mitochondrial redox/bioenergetic pathways and inflammatory tone. CCO-centered mechanistic framing is best established near ~ 800–850 nm, whereas longer wavelengths (e.g., ~ 1064–1070 nm) may involve additional initiating mechanisms with downstream convergence on shared redox/bioenergetic and inflammatory pathways. Across demyelination and spinal cord injury models, appropriately dosed PBM has been reported to reduce inflammatory glial readouts and to associate with improved myelin/axon-related endpoints and functional measures, although mechanistic certainty varies across models. Human evidence remains early but broadly supports safety; a randomized trial in moderate traumatic brain injury reported treatment-related changes in diffusion-MRI WM metrics, while small dementia and chronic-injury studies report heterogeneous cognitive and physiological signals. Given dose dependence and depth-limited transcranial delivery, we synthesize mechanism-informed, dose-aware reporting guidance and WM-anchored outcome frameworks that pair diffusion MRI/DTI with interpretable biomarkers (e.g., NfL, GFAP, sTREM2) and thermally controlled sham designs. We also note potential indirect/systemic contributions that could help reconcile depth–dose constraints with deeper WM effects.

Extracellular vesicles (EVs) are nanoscale membrane-bound particles that mediate intercellular communication by transferring proteins, nucleic acids, lipids, and metabolites. Increasing evidence implicates EVs in Alzheimer’s disease (AD) pathogenesis through the propagation of amyloid-β, tau, and neuroinflammatory signals across neural and glial networks. In parallel, EVs isolated from biofluids have emerged as promising sources of disease-associated biomarkers and potential therapeutic carriers. This review aims to synthesize current evidence on EV-mediated mechanisms in AD, evaluate the diagnostic value of EV-associated biomarkers, and discuss emerging EV-based and bioengineered therapeutic strategies. We summarize how EVs derived from neurons, astrocytes, microglia, and peripheral cells contribute to amyloid-β and tau spread, neuroinflammation, synaptic dysfunction, and metabolic stress in AD. Disease-associated alterations in EV cargo from blood, cerebrospinal fluid, and urine are critically assessed for biomarker applications. We further highlight advances in EV bioengineering, including cargo loading, surface modification, targeting strategies, and modulation of EV biogenesis. Finally, key translational challenges—such as EV heterogeneity, biodistribution, immune clearance, and standardization—are discussed to define future directions for leveraging EVs as diagnostic and therapeutic platforms in AD.

Brain organoids represent three-dimensional structures that allow for human-specific studies in brain development, pathology and therapeutics. These self-organizing systems, formed through the differentiation of human pluripotent stem cells, can mimic important cellular and molecular events of brain development and therefore serve as a platform for the investigation of neurodevelopmental and neurodegenerative diseases, brain injuries, and tumorigenesis. Although brain organoids show promising perspectives in the study of human physiology, existing brain organoid platforms are hindered by issues of under vascularization, immaturity and protocol variability. Nevertheless, the rapid development of new bioengineering, microfluidic and multi-omics tools and approaches allows us to overcome existing problems and increase the physiological significance of these organoids. Brain organoid transplantation and functional studies further enhance the applications of brain organoids in drug screening, disease modeling and personalized medicine. Here, we provide an overview of recent developments in the field of brain organoid cultures, functional characteristics and translational applications.

Chronic cerebral hypoperfusion (CCH) profoundly affects patient well-being and has been proposed as a risk factor for cognitive impairment and dementia. However, due to the limited understanding of the pathophysiology of CCH, there are currently no effective preventive or therapeutic approaches for CCH-associated cognitive impairment. Therefore, identifying new targets for CCH is essential to bridge this knowledge gap. In this study, we sought to determine whether enhanced myelination could prevent cognitive impairment associated with CCH. Experimental CCH was induced via bilateral common carotid artery occlusion (BCCAO) in rats, and clemastine, a well-established pro-myelinating agent, was administered to boost myelin renewal. A series of behavioral tests was performed to assess learning and memory. We found that animals exhibited profound cognitive deficits 3 months after BCCAO, accompanied by significant myelin loss, structural disruption at the nodes of Ranvier, and synaptic dysfunction in various brain regions, without notable neuronal loss and oligodendrocyte apoptosis. Importantly, pharmacological enhancement of myelination preserved dendritic spine density and prevented synaptic loss, cognitive deficits, and neurovascular dysfunction following BCCAO. These findings suggest that clemastine may represent a promising therapeutic option for CCH-associated cognitive impairment.

Myelin is a multilamellar membrane that surrounds axons in the vertebrate nervous system. Properly functioning myelin is essential for the rapid conduction of nerve impulses, and it metabolically supports axonal integrity. Emerging evidence indicates that myelin is also involved in various aspects of cognition, with adaptive myelination playing a critical role in memory consolidation and motor learning. However, these physiological processes can be disrupted in various diseases. Understanding the mechanisms underlying myelin pathology is therefore essential for the development of targeted therapies for associated medical conditions. This review provides a comprehensive overview of the role of myelin in neural function, with a particular focus on adaptive myelination in cognition. We also highlight myelin dysfunction and the underlying mechanisms in the aging brain, as well as in diverse brain disorders and neurological conditions, including neurodegenerative diseases, psychiatric conditions, brain injuries, chemotherapy-related cognitive impairment, and neurological symptoms associated with COVID-19. Furthermore, we discuss the therapeutic potential of recently identified pro-myelinating compounds in aging-associated cognitive decline and brain disorders, as well as the future of remyelination therapies. Current evidence suggests that restoring functional myelin may serve as a therapeutic strategy for various medical conditions associated with myelin dysfunction.

Recent research suggests that photobiomodulation therapy (PBMT) positively impacts the vascular function associated with various cerebrovascular diseases. Nevertheless, the specific mechanisms by which PBMT improves vascular function remain ambiguous. Since endothelial nitric oxide synthase (eNOS) is crucial in regulating vascular function following cerebral ischemia, we investigated whether eNOS is a key element controlling cerebrovascular function and the senescence of vascular endothelial cells following PBMT treatment. Both rat photothrombotic (PT) stroke and in vitro oxygen–glucose deprivation (OGD)-induced vascular endothelial injury models were utilized. We demonstrated that treatment with PBMT (808 nm, 350 mW/cm², 2 min/day) for 7 days significantly reduced PT-stroke-induced vascular permeability. Additionally, PBMT inhibited the levels of endothelial senescence markers (senescence green and p21) and antiangiogenic factor (endostatin), while increasing the phospho-eNOS (Ser1177) in the peri-infarct region following PT stroke. In vitro study further indicated that OGD increased p21, endostatin, and DNA damage (γH2AX) levels in the brain endothelial cell line, but they were reversed by PBMT. Intriguingly, the beneficial effects of PBMT were attenuated by a NOS inhibitor. In summary, these findings provide novel insights into the role of eNOS in PBMT-mediated protection against cerebrovascular senescence and endothelial dysfunction following ischemia. The use of PBMT as a therapeutic is a promising strategy to improve endothelial function in cerebrovascular disease.