02435nas a2200361   4500000000100000008004100001260001500042100002100057700001700078700001500095700001900110700001900129700001500148700002200163700001500185700001600200700001700216700001600233700001500249700001700264700001700281700002300298700003000321700001900351700002200370700001800392700001700410245006500427856005300492300001600545490000800561520150400569       2025                            d  c2025-10-211 aAlice E. Stanton1 aAdele Bubnys1 aEmre Agbas1 aBenjamin James1 aDong Shin Park1 aAlan Jiang1 aRebecca L. Pinals1 aLiwang Liu1 aNhat Truong1 aAnjanet Loon1 aColin Staab1 aOyku Cerit1 aHsin-Lan Wen1 aDavid Mankus1 aMargaret E. Bisher1 aAbigail K. R. Lytton-Jean1 aManolis Kellis1 aJoel W. Blanchard1 aRobert Langer1 aLi-Huei Tsai00aEngineered 3D immuno-glial-neurovascular human miBrain model  uhttps://www.pnas.org/doi/10.1073/pnas.2511596122  ae25115961220 v1223 aPatient-specific, human-based cellular models integrating a biomimetic blood–brain barrier, immune, and myelinated neuron components are critically needed to enable accelerated, translationally relevant discovery of neurological disease mechanisms and interventions. To construct a human cell-based model that includes these features and all six major brain cell types needed to mimic disease and dissect pathological mechanisms, we have constructed, characterized, and utilized a multicellular integrated brain (miBrain) immuno-glial-neurovascular model by engineering a brain-inspired 3D hydrogel and identifying conditions to coculture these six brain cell types, all differentiated from patient induced pluripotent stem cells. miBrains recapitulate in vivo–like hallmarks inclusive of neuronal activity, functional connectivity, barrier function, myelin-producing oligodendrocyte engagement with neurons, multicellular interactions, and transcriptomic profiles. We implemented the model to study Alzheimer’s Disease pathologies associated with APOE4 genetic risk. APOE4 miBrains differentially exhibit amyloid aggregation, tau phosphorylation, and astrocytic glial fibrillary acidic protein. Unlike the coemergent fate specification of glia and neurons in other organoid approaches, miBrains integrate independently differentiated cell types, a feature we harnessed to identify that APOE4 in astrocytes promotes neuronal tau pathogenesis and dysregulation through crosstalk with microglia.