Molecularly Deconstructing Sexual Dimorphism in Early Brain Injury Post Aneurysmal Subarachnoid Hemorrhage: Leveraging Human Brain Organoids and Patient Biofluids

Despite growing recognition that early brain injury [EBI] from cerebral edema significantly contributes to death and disability after aneurysmal subarachnoid hemorrhage [aSAH]—there is a critical gap in understanding the molecular mediators driving injury in humans. This limits treatment development. Women [♀] are at higher risk of poor outcome; although EBI mechanisms likely contribute, these remain unexplored. The long-term goal is to molecularly endotype clinical EBI and advance targeted therapies that improve outcome. This R01 leverages human cerebrospinal fluid [CSF] and forebrain organoids [HBO] to address important knowledge gaps in vectors and molecular signals of neuroglial damage and EBI post-aSAH. Since the brain is bathed in CSF, abnormal signals in aSAH CSF can rapidly and diffusely permeate. CSF is thus a highly plausible vector for disseminating signals causing EBI, which often occurs far from the aneurysm site. The objective is to molecularly deconstruct CSF as a conduit for toxin exposure that drives neuroglial injury and EBI. We use serially collected CSF post- aSAH from matched ♀/♂ patients to evaluate its molecular impact on ♀/♂ human brain health and isolate secreted factors. Brain health is modeled in HBOs with human cortical cell types and 3D tissue-like organization. EBI is quantified on computed tomography [CT] using validated methods (subarachnoid hemorrhage early brain edema score, selective sulcal volume). The central hypothesis is that human aSAH CSF is a paracrine mediator of EBI, with more toxic signals in ♀ vs ♂ CSF (severity matched) that can be targeted. This is supported by our pilot data from HBOs, single-cell transcriptomics [scRNASeq], and proteomics. Aim 1 tests neurobiological effects of ♀/♂ CSF from aSAH patients on ♀/♂ HBOs. Aim 2 defines immune contributions to neuroglial injury after aSAH in brain assembloids with microglia ([HBA-Ms], 2A) and molecular signatures of CSF-cells associated with EBI (scRNAseq, 2B). HBOs/HBA-Ms in Aims 1-2A are exposed to aSAH CSF for 1 week; impact on tissue health is assessed with scRNASeq and immunohistochemistry. HBO/HBA-M-CSF cultures are also exposed to drugs informed by pilot data to evaluate pharmacodynamic response. Aim 3A quantifies CSF proteomic signatures of EBI in patients. 3B reconstitutes top analytes from 3A to test on HBO/A-Ms. 3C analyzes contributions of HBO/A-M substrate to EBI by testing ‘spent media’ from cultures after CSF exposure (from Aims 1-2). Overlapping pathways across aims identify high-yield biomarkers/druggable targets. This is feasible given exciting pilot data, an existing biobank with robust enrollment, a strong multidisciplinary team and bioinformatic pipelines. It is innovative as the first aSAH study to use human organoids, molecularly deconstruct human CSF as a conduit for toxin exposure that drives EBI and create first-in-human single-cell transcriptomic atlases of CSF response in aSAH. Completion of this work will establish CSF as a driver of human neuroglial injury and EBI, define secreted and substrate contributions to injury, and delineate factors underlying higher ♀ clinical risk. This is critical to advance a transformative precision-medicine approach to understand and treat EBI in aSAH. Project Number: 1R01NS143164-01A1 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of Neurological Disorders and Stroke (NINDS) | Principal Investigator: Ruchira Jha | Institution: BARROW NEUROLOGICAL INSTITUTE AT ST. JOSEPH'S HOSPITAL AND MEDICAL CENTER, PHOENIX, AZ | Award Amount: $619,392 | Activity Code: R01 | Study Section: Brain Injury and Neurovascular Disorders Study Section[BIND] View on NIH RePORTER: https://reporter.nih.gov/project-details/11290705