Viscoelastic high-molecular-weight hyaluronic acid hydrogels support rapid glioblastoma cell invasion with leader-follower dynamics.

Hyaluronic acid (HA), the primary component of brain extracellular matrix, is increasingly used to model neuropathological processes, including glioblastoma (GBM) tumor invasion. While elastic hydrogels based on crosslinked low-molecular-weight (LMW) HA are widely exploited for this purpose and have proven valuable for discovery and screening, brain tissue is both viscoelastic and rich in high-MW (HMW) HA, and it remains unclear how these differences influence invasion. To address this question, hydrogels comprised of either HMW (1.5 MDa) or LMW (60 kDa) HA are introduced, characterized, and applied in GBM invasion studies. Unlike LMW HA hydrogels, HMW HA hydrogels relax stresses quickly, to a similar extent as brain tissue, and to a greater extent than many conventional HA-based scaffolds. GBM cells implanted within HMW HA hydrogels invade much more rapidly than in their LMW HA counterparts and exhibit distinct leader-follower dynamics. Leader cells adopt dendritic morphologies, similar to invasive GBM cells observed in vivo. Transcriptomic, pharmacologic, and imaging studies suggest that leader cells exploit hyaluronidase, an enzyme strongly enriched in human GBMs, to prime a path for followers. This study offers new insight into how HA viscoelastic properties drive invasion and argues for the use of highly stress-relaxing materials to model GBM.

FATP5 Is Indispensable for the Growth of Intrahepatic Cholangiocarcinoma.

Altered lipid metabolism is a common hallmark of various cancers, including intrahepatic cholangiocarcinoma (ICC), a highly lethal carcinoma that lacks effective treatment options. To elucidate the lipid metabolism changes in ICC, we coupled the expression of the firefly luciferase gene (FFL) to AKT1 (AKT-FFL) via an IRES linker, and then hydrodynamically injected mice with AKT-FFL and Notch1 intracellular cytoplasmic domain (NICD) to establish a luciferase-positive ICC model. This model not only enabled us to monitor and quantify tumor growth by injecting the mice with luciferin, but also allowed us to assess the fatty acid uptake rate by injecting the mice with free fatty acid luciferin (FFA-Luc). The ICC model exhibited robust uptake of exogenous fatty acids compared with the HCC model induced by AKT-FFL/ neuroblastoma Ras (Ras). Lipidomics analysis showed a dramatically higher level of fatty acid in ICC, further supporting the increased fatty acids uptake. Mechanistic studies identified FATP5 as the predominant mediator of fatty acid uptake required for ICC growth using Fatp5 knockout mice and AAV-based shRNA silencing of Fatp5. Our study discovered a novel therapeutic target for the treatment of ICC and shed light on the contributions of lipid metabolism to ICC development. IMPLICATIONS: This study provides the first in vivo evidence that FATP5 is a potential therapeutic target for treating ICC.

Human iPSC-Derived Proinflammatory Macrophages cause Insulin Resistance in an Isogenic White Adipose Tissue Microphysiological System.

Chronic white adipose tissue (WAT) inflammation has been recognized as a critical early event in the pathogenesis of obesity-related disorders. This process is characterized by the increased residency of proinflammatory M1 macrophages in WAT. However, the lack of an isogenic human macrophage-adipocyte model has limited biological studies and drug discovery efforts, highlighting the need for human stem cell-based approaches. Here, human induced pluripotent stem cell (iPSC) derived macrophages (iMACs) and adipocytes (iADIPOs) are cocultured in a microphysiological system (MPS). iMACs migrate toward and infiltrate into the 3D iADIPOs cluster to form crown-like structures (CLSs)-like morphology around damaged iADIPOs, recreating classic histological features of WAT inflammation seen in obesity. Significantly more CLS-like morphologies formed in aged and palmitic acid-treated iMAC-iADIPO-MPS, showing the ability to mimic inflammatory severity. Importantly, M1 (proinflammatory) but not M2 (tissue repair) iMACs induced insulin resistance and dysregulated lipolysis in iADIPOs. Both RNAseq and cytokines analyses revealed a reciprocal proinflammatory loop in the interactions of M1 iMACs and iADIPOs. This iMAC-iADIPO-MPS thus successfully recreates pathological conditions of chronically inflamed human WAT, opening a door to study the dynamic inflammatory progression and identify clinically relevant therapies.

Generation of two human iPSC lines with Exon 3 mutations in BCL2-Associated Athanogene 3 (BAG3) from dilated cardiomyopathy patients.

Dilated cardiomyopathies (DCM) are one of the main causes of heart failure as one ages. BAG3 is a chaperone protein that is heavily implicated in the development of DCM and speed of progression toward heart failure. Here we generate two human iPSC lines from individuals with mutations in exon 3 of BAG3 and provide validation of their pluripotency and ability to differentiate toward the three primary germ layers. These two cell lines can help our understanding of BAG3 and its role in DCM by providing a good model for BAG3 inactivation and insufficiency.