Youssef Zaim Wadghiri

Cerebral amyloid angiopathy (CAA) is a prevalent cerebrovascular pathology in AD and contributes to amyloid-related imaging abnormalities (ARIA), a major complication of current anti-amyloid immunotherapy. Despite its growing clinical importance, critical gaps remain in the development of reliable biomarkers for antemortem diagnosis of CAA. Squirrel monkeys (SQMs) are a valuable non-human primate model with translational relevance due to their universal propensity to develop abundant CAA and spontaneous ARIA in geriatric animals. The present study employed R ₂ *, the apparent transverse relaxation rate, which is sensitive to susceptibility-related tissue properties, including iron content and blood oxygenation levels, to monitor age-related brain pathology in SQMs with varying CAA severity. Young, early geriatric, and late geriatric SQMs underwent 7T MRI using a dual-purpose T ₂ *-w 3D multi-gradient-echo sequence for high-resolution anatomy and quantitative R ₂ * mapping, alongside T ₂ -w/FLAIR imaging. Whole-brain and gray matter R ₂ * increased with age. In contrast, white matter R ₂ * showed an initial increase followed by a late-life reversal, likely reflecting age-related changes in myelin integrity, tissue microstructure, and tissue water content. MRI-histopathology correlation linked T ₂ *-w MRI hypointensities to CAA-positive iron-laden vessels associated with perivascular inflammation and, in some cases, hemosiderin deposits. Here we confirmed the occurrence of ARIA-H and ARIA-E events in geriatric animals. SQMs provided a valuable opportunity to examine the underlying pathology of spontaneous ARIA-E, revealing distinctive tissue signatures associated with its manifestation. ARIA-E hyperintensities were characterized by reactive gliosis and BBB disruption, whereas more advanced lesions exhibited perivascular lymphocytic infiltration and evidence of myelin and axonal injury. The current study presents compelling evidence linking R ₂ * alterations with CAA severity and ARIA-related tissue injury, providing a foundation for further advancing early detection of CAA, ARIA risk assessment, and treatment strategies.

Vascular mapping of fixed postmortem human brain tissue remains biologically complex and technically challenging because postmortem changes, including clot contraction and fragmentation, vascular collapse, and fixation‐induced alterations, substantially affect vascular MRI contrast. Furthermore, the mechanisms governing vascular contrast in postmortem MRI remain incompletely understood. In this study, we aim to determine the feasibility and reliability of using blood clot formation as a susceptibility contrast source to improve vascular visibility and enable quantitative assessment on ex vivo MRI. Postmortem brain hemispheres and tissue blocks were imaged to assess vascular conspicuity in the cortex, hippocampus, and white matter. Coagulated blood signal was clearly observed within the postmortem brain surface vasculature, with intact clots in small vessels and partial or discontinuous clotting in larger vessels. High‐resolution gradient echo (GRE) imaging of tissue blocks enabled detailed reconstruction of local vascular networks, including intrahippocampal vasculature, for vessel density quantification. Quantitative analysis demonstrated markedly shorter T2* values for blood clots (6.6 ± 2.0 ms) compared with gray matter (34.8 ± 8.9 ms) and white matter (19.1 ± 3.6 ms) at 7 T, resulting in appropriate vascular contrast and conspicuity. Histological hematoxylin–eosin and Luxol Fast Blue staining confirmed intravascular clot formation and localization. These findings demonstrate that blood clots can act as an intrinsic contrast for mesoscopic vascular MRI in the postmortem human brain, enabling detailed assessment of microvascular changes and their pathological correlates relevant to vascular contributions to cognitive impairment and dementia.

APG157DS is a multi-component investigational drug which is currently the subject of multiple cancer trials. It has shown promising efficacy in patients with head and neck cancer. We report its immuno-modulatory effect in a syngeneic mouse model of glioblastoma (GBM). Long-term treatment with APG157DS led to durable tumor remission in 50% of mice, while all vehicle-treated mice reached humane endpoints within 42 days. Mechanistically, the drug induced selective repolarization of tumor-associated macrophages (TAMs) from an immunosuppressive Arg1^high/iNOS^low phenotype to a tumoricidal Arg1^low/iNOS^high state, accompanied by increased intratumoral recruitment of activated (NKp46+) natural killer cells and CD8+ cytotoxic T-cells. APG157DS also suppressed vascular endothelial growth factor (VEGF) and Hypoxia-inducible factor 1-alpha (HIF-1α) expression in tumors, further impairing tumor growth. Notably, APG157DS did not elicit off-target macrophage activation in peripheral tissues such as the spleen, highlighting its selective immune targeting. These findings provide a mechanistic rationale for further clinical development of APG157DS in GBM and potentially other immune-evasive cancers.

Reprogramming of macrophages into the inflammatory state (also known as M1) is currently considered as an effective way of eliminating cancer cells, but systemic deployment of this strategy is likely to induce dangerous autoimmune reactions. Consequently, converting immunosuppressive M2-type macrophages into M1 systemically is not a safe and effective therapeutic approach against cancer. Through cleavable covalent linking of curcumin to the chemotherapeutic agent Paclitaxel (Taxol), we have created a novel prodrug (STO-1) that, upon intravenous delivery, selectively reprograms tumor-associated microglia and macrophages (TAMs) and eliminates glioblastoma (GBM) without triggering autoimmunity. Demonstrating its therapeutic efficacy, prolonged treatment of six orthotopic GBM-bearing mice with STO-1 resulted in 67% long-term survival, with three surviving mice exhibiting complete tumor clearance and one displaying minimal residual disease, as confirmed by high-resolution ex vivo T2-weighted MRI 85 days after tumor inoculation. In contrast, the vehicle-treated mice displayed extensive intracranial tumors with edema and hemorrhage. Mechanistically, scRNA-seq analysis indicated induction of multiple M1-associated transcripts (ccrl2, cxcl9, ccr2, ccl5) consistent with robust TAMs reprogramming. In striking contrast to the M2⟶M1 reprogramming of TAMs, M1-type macrophages were suppressed in the spleens of STO-1-treated cancer-free mice. Therefore, STO-1 induces selective anti-tumor immunity and GBM elimination without triggering systemic autoimmune reactions.

Reprogramming of macrophages into the inflammatory state (also known as M1) is currently considered as an effective way of eliminating cancer cells, but, systemic deployment of this strategy is likely to induce dangerous autoimmune reactions. Consequently, converting immunosuppressive M2-type macrophages into M1 systemically is not a safe and effective therapeutic approach against cancer. Through cleavable covalent linking of curcumin to the chemotherapeutic agent Paclitaxel (Taxol), we have created a novel prodrug (STO-1) that, upon intravenous delivery, selectively reprograms tumor-associated microglia and macrophages (TAMs) and eliminates glioblastoma (GBM) without triggering autoimmunity. Demonstrating its therapeutic efficacy, prolonged treatment of six orthotopic GBM-bearing mice with STO-1 resulted in 67% long-term survival, with three surviving mice exhibiting complete tumor clearance and one displaying minimal residual disease, as confirmed by high-resolution ex vivo T2-weighted MRI 85 days after tumor inoculation. In contrast, the vehicle-treated mice displayed extensive intracranial tumors with edema and hemorrhage. Mechanistically, scRNA-seq analysis indicated induction of multiple M1-associated transcripts (ccrl2, cxcl9, ccr2, ccl5) consistent with robust TAMs reprogramming. In striking contrast to the M2M1 reprogramming of TAMs, M1-type macrophages were suppressed in the spleens of STO-1-treated cancer-free mice. Therefore, STO-1 induces selective anti-tumor immunity and GBM elimination without triggering systemic autoimmune reactions.

Embryonic development in many species, including case reports in humans, can be temporarily halted before implantation during a process called diapause. Facultative diapause occurs under conditions of maternal metabolic stress such as nursing. While molecular mechanisms of diapause have been studied, a natural inducing factor has yet to be identified. Here, we show that oxytocin induces embryonic diapause in mice. We show that gestational delays were triggered during nursing or optogenetic stimulation of oxytocin neurons simulating nursing patterns. Mouse blastocysts express oxytocin receptors, and oxytocin induced delayed implantation-like dispersion in cultured embryos. Last, oxytocin receptor–knockout embryos transferred into wild-type surrogates had low survival rates during diapause. Our results indicate that oxytocin coordinates timing of embryonic development with uterine progression through pregnancy, providing an evolutionarily conserved mechanism for ensuring successful reproduction.

The mouse is the mammalian model of choice for investigating cardiovascular biology, given our ability to manipulate it by genetic, pharmacologic, mechanical, and environmental means. Imaging is an important approach to phenotyping both function and structure of cardiac and vascular components. This review details commonly used imaging approaches, with a focus on echocardiography and magnetic resonance imaging, with brief overviews of other imaging modalities. In this update, we also emphasize the importance of rigor and reproducibility in imaging approaches, experimental design, and documentation. Finally, we briefly outline emerging imaging approaches but caution that reliability and validity data may be lacking. © 2024 Wiley Periodicals LLC.

Triple-negative breast cancer (TNBC) lacks expressed protein targets, making therapy development challenging. Hydrogels offer a promising new route in this regard by improving the chemotherapeutic efficacy through increased solubility and sustained release. Moreover, subcutaneous hydrogel administration reduces patient burden by requiring less therapy and shorter treatment times. We recently established the design principles for the supramolecular assembly of single-domain coiled-coils into hydrogels. Using a modified computational design algorithm, we designed Q8, a hydrogel with rapid assembly for faster therapeutic hydrogel preparation. Q8 encapsulates and releases doxorubicin (Dox), enabling localized sustained release via subcutaneous injection. Remarkably, a single subcutaneous injection of Dox-laden Q8 (Q8•Dox) significantly suppresses tumors within just 1 week. This work showcases the bottom-up engineering of a fully protein-based drug delivery vehicle for improved TBNC treatment via noninvasive localized therapy.