Siano and colleagues provided evidence that soluble, nuclear microtubule associated protein tau (MAPT/tau) associated with reshaping the neuronal transcriptome in a manner that most strongly resembles intermediate (proAD) stages of human AD, not the earliest or latest phases. Mechanistically, tau overabundance associates with a reduction in heterochromatin markers -heterochromatin protein 1 alpha (HP1α) and histone H3 lysine 9 trimethylation (H3K9me3) -both in vitro cell-based systems and in human temporal cortex, and the differentially expressed genes align with histone acetylation changes observed in AD brains. These findings support a model in which nuclear tau drives epigenetic modulation and transcriptional reprogramming prior to irreversible degeneration in AD. Complementing this, a large postmortem temporal cortex cohort shows decreased CAMKK2, TF, and TFRC in AD (and TFRC in PD as well), alongside increased iron content correlating with TF/TFRC levels -implicating disrupted receptor-mediated iron handling in neurotoxicity 3 . Together these studies position CAMKK2 as a mechanistic hub linking Ca²⁺ signaling to iron homeostasis, with regional and stage specificity: TFRC loss emerged late in hippocampus but was evident earlier in cortex. Translationally, they argue for biomarkers that pair quantitative susceptibility mapping (QSM) Magnetic resonance imaging for measuring brain iron content 4 5 with a plasma or cerebrospinal fluid (CSF) TF/TFRC and AD biomarker panels (amyloid-β 42/40 ratio, phosphorylated tau at threonine 181, glial fibrillary acidic protein, neurofilament light chain, phosphorylated tau at threonine 217 and apolipoprotein E ε4 allele) 6 , and for therapies that restore CAMKK2 axis activity or stabilize TF/TFRC trafficking.Huang et al. reviewed the dual, stage-dependent roles of TREM2 in tauopathy. TREM2 signaling can suppress glycogen synthase kinase 3 beta/cyclin-dependent kinase 5 (GSK3β/CDK5) activity and reduce tau phosphorylation; yet chronic or mis-timed activation may exacerbate amyloid-β (Aβ)-associated tau seeding and spread. Soluble TREM2 (CSF) rises early during AD pathogenesis and correlates with t-tau/p-tau, and genetic variants of TREM2, notably R47H (arginine-to-histidine) modulate microglial phenotypes. These dynamics reinforce a precision-timing concept: TREM2 agonism may be beneficial when it promotes disease-associated microglia stage 2 (DAM2) transitions, but harmful if it sustains microgliosis without clearing Aβ in seeding-permissive contexts.Yi et al. demonstrate that fangchinoline (a natural bisbenzylisoquinoline) promotes autophagy-lysosome degradation of beta-secretase 1 (BACE1), reduces amyloidogenic amyloid beta precursor protein (APP) processing, and improves cognition in an Aβ1-42 mouse model while enhancing antioxidant programs (nuclear factor erythroid 2-related factor 2/ heme oxygenase-1/ superoxide dismutase 1)and reducing hydrogen peroxide (H₂O₂) and inducible nitric oxide synthase (iNOS). While a single plant derived alkaloid cannot address AD's full complexity, these data highlight autophagy induction as a practical lever that simultaneously lowers Aβ drive and attenuates oxidative stress, thereby relieving pressure on pathways that may fuel AD pathogenesis.The O-linked-β-N-acetylglucosamine (O-GlcNAc) post-translational modificationaddition of a single N-acetylglucosamine (GlcNAc) to serine/threonine residues -has been proposed to modulate the amyloidogenic processing of APP, motivating pharmacological strategies that enhance O-GlcNAcylation. Building on this rationale, Garcia et al. tested the selective O-GlcNAcase (OGA) inhibitor thiamet-G to increase O-GlcNAcylation and potentially alleviate progressive AD pathology in female transgenic TgF344-AD rats. The results were mixed: plaque burden did not change, microglial reactivity did not increase, and noradrenergic axon density was not rescued. By contrast, astrocytes adjacent to plaques showed greater morphological complexity (consistent with a more encapsulating "glial border"), and dystrophic axon morphology was reduced. Overall, these data suggest an astrocyte-proximal benefit coexisting with neutral effects on plaques and microglia, reinforcing the need for cell-and compartment-specific readouts when evaluating metabolic/proteostasis interventions.Teng et al. review how pathogen exposure (viruses, bacteria, parasites) may shape AD risk and progression not only through inflammation and barrier injury, but also by modulating RNA 5-methylcytosine (m⁵C) in host cells. The writers/readers/erasers (e.g., NSUN, ALYREF, TET family proteins) influence RNA stability and immune programs; alterations in m⁵C have been linked to pathogen replication, host antiviral signaling, and, increasingly, to neuropathology and cognition. This positions epitranscriptomic drift -potentially infectiontriggered-as a plausible upstream driver that intersects with the nuclear tau-chromatin axis and with microglial immune state via transcript control.Collectively, the contributions in this research topic argue that AD is best understood as a network disorder in which neuronal, glial, vascular, and immune programs interact across time through a set of convergent axes: nuclear tau-chromatin remodeling that reprograms transcription at intermediate stages; a Ca²⁺-CAMKK2-transferrin signaling hub that links calcium signaling to brain iron handling; microglial state transitions gated by TREM2 that can contain or propagate tau; proteostatic control via autophagy that lowers amyloidogenic drive and oxidative stress; and infection-linked m⁵C epitranscriptomic drift that may recalibrate innate immune tone and intersect with amyloid/tau biology. Together, these insights motivate an integrated, stage-aware roadmap for therapy development.
Mohammad Golam Sabbir (Thu,) studied this question.