Biology subjects

Woods, P. S.

Publications and source records attributed to Woods, P. S..

10 recordsLinked to original sources

bioRxiv2026

Fructose Dendrimer-Based Poly Ionic Complexes for Glut5-Specific Intracellular Drug Delivery in Murine Brain

Glial cells play essential roles in maintaining neural tissue homeostasis and limiting the spread of injury-induced neuroinflammation, yet their dysfunction can also exacerbate neurodegenerative, neuroimmune, and neurodevelopmental disorders. Therapeutic targeting of specific glial cell populations would open up new treatment possibilities, but currently available viral and non-viral delivery vehicles are limited by carrier toxicity as well as poor delivery efficiency and specificity. To work towards new glia-targeted, non-viral delivery vehicles, we performed an in silico analysis on neural cell specific RNA-Seq datasets in mice to identify surface molecules differentially enriched on neurons, astrocytes, and microglia. We identified Slc2a5 (Glut5) as a microglia-enriched transporter and validated its microglia specific expression in healthy murine neural tissue using RNA in situ hybridization. By employing a sequential thiol-ene and enzymatic catalyzed reaction scheme, we synthesized polyelectrolytic dendrimers with multivalent presentation of fructose, the natural ligand for Glut5, and formulated nano-sized polyionic complexes (PICs) loaded with protein or nucleic acid cargo by mixing oppositely charged dendrimers. Fructose functionalized PICs lacking cationic surface charge enabled fructose-dependent intracellular protein delivery to Glut5-expressing human breast cancer cells (MCF-7) and mouse fibroblasts, while restricting uptake by Glut5-negative mouse astrocytes, confirming transporter-dependent selectivity in vitro. Fructose functionalized PICs resulted in minimal neuroinflammation when injected into mouse striatum at 1 mg/ml but elicited concentration-dependent neural tissue toxicity at higher doses. Fructose-PICs failed to achieve microglia specific intracellular delivery of functional proteins when injected into healthy neural tissue but aided in directing protein delivery to microglia and astrocytes at ischemic stroke lesions. Together, our findings demonstrate proof-of-principle for using in silico RNA-seq screening workflows to identify cell specific surfaceome targets and incorporating that insight into a modular biomaterial platform for targeted drug delivery.

bioengineering↗

bioRxiv2026

Transfer Learning Enables Drug-Target Interaction Prediction in Data-Scarce One-Carbon Metabolism

Predicting drug-target interactions (DTIs) with deep learning offers opportunities to accelerate drug discovery, yet performance is constrained by the scarcity of target-specific training data. This is a particular challenge for mitochondrial one-carbon (1C) pathway enzymes, which are attractive therapeutic targets but remain pharmacologically understudied. Mitochondrial 1C metabolism supplies glycine, reducing equivalents, and 1C units critical for nucleotide synthesis, and has emerged as a key pathway in cancer and fibrosis. SHMT2 and MTHFD2, two key 1C enzymes, support collagen production in fibroblasts, blocking either prevents TGF-{beta}-induced glycine and collagen accumulation. Here, we developed transfer learning-based deep learning models to predict interactions between approved drugs and SHMT2 or MTHFD2 despite minimal target-specific training data, pre-training on large datasets from related enzymes before fine-tuning to these targets. Virtual screening of the DrugBank library identified six candidates, three of which, Carbimazole, Crizotinib, and GSK2018682 reduced TGF-{beta}-induced collagen production and glycine accumulation in human lung fibroblasts, demonstrating transfer learning as a strategy for repurposable drug identification in data-scarce metabolic targets.

bioinformatics↗

bioRxiv2026

Predicting recovery trajectories and injury severity following partial crush spinal cord injury in mice

The partial crush spinal cord injury (SCI) model enables preclinical testing of experimental therapies in mice, but substantial inter-animal variability in recovery outcomes confounds efficacy assessments. Here, we used open field behavioral data collected during the first 3 days post partial thoracic SCI to generate an Acute Functional Score (AFS) that defined three subgroups with divergent recovery trajectories. Applying latent class growth analysis and growth mixture modeling to open field and grid walk testing data, we demonstrated 83-92% prediction accuracy for AFS-defined recovery trajectories. The three subgroups differed significantly in treadmill kinematics and histological assessments of lesion size and astrocyte bridging. Applying the recovery trajectory framework to mice receiving saline or biomaterial vehicle injections at 3 days post-SCI revealed robust predictive accuracy while exposing disproportionate injury severity distributions between experimental groups. The approach enables individualized post-SCI recovery characterization that can neutralize procedural bias, minimize animal numbers, and provide a probabilistic basis for evaluating whether interventions enhance or suppress wound repair processes. Our findings establish a foundation for improving preclinical SCI study design and accelerating identification of effective therapies.

neuroscience↗

bioRxiv2024

Role of Arginine and its Metabolism in TGF-β-Induced Activation of Lung Fibroblasts

Arginine is a conditionally essential amino acid with known roles in protein production, nitric oxide synthesis, biosynthesis of proline and polyamines, and regulation of intracellular signaling pathways. Arginine biosynthesis and catabolism have been linked to TGF-{beta}-induced activation of fibroblasts in the context of pulmonary fibrosis; however, a thorough study on the metabolic and signaling roles of arginine in the process of fibroblast activation has not been conducted. Here, we used metabolic dropouts and labeling strategies to determine how activated fibroblasts utilize arginine. We found that arginine limitation leads to activation of GCN2 while inhibiting TGF-{beta}-induced mTORC1 activation and collagen protein production. Extracellular citrulline could rescue the effect of arginine deprivation in an ASS1-dependent manner. Using metabolic tracers of arginine and its precursors, we found little evidence of arginine synthesis or catabolism in lung fibroblasts treated with TGF-{beta}. Extracellular ornithine or glutamine were the primary sources of ornithine and polyamines, not arginine. Our findings suggest that the major role for arginine in lung fibroblasts is for charging of arginyl-tRNAs and for promotion of mTOR signaling. Highlights- Arginine depletion inhibits TGF-{beta}-induced transcription in human lung fibroblasts (HLFs). - Arginine is not significantly catabolized in HLFs either through NOS or ARG dependent pathways. - Extracellular glutamine and ornithine are the primary sources of polyamines in lung fibroblasts. - The primary role of arginine in lung fibroblasts is for signaling through mTOR and GNC2.

cell biology↗

bioRxiv2024

HIF-1α regulates mitochondrial function in bone marrow-derived macrophages, but not in tissue-resident alveolar macrophages

HIF-1 plays a critical role in shaping macrophage phenotype and effector function. We have previously shown that tissue-resident alveolar macrophages (TR-AMs) have extremely low glycolytic capacity at steady-state, but can shift toward glycolysis under hypoxic conditions. Here, using inducible HIF-1 knockout (Hif1a-/-) TR-AMs and bone marrow-derived macrophages (BMDMs) and show that TR-AM HIF-1 is required for the glycolytic shift under prolyl hydroxylase inhibition, but is dispensable at steady-state for inflammatory effector function. In contrast, HIF-1 deletion in BMDMs led to diminished glycolytic capacity at steady-state and reduced inflammatory capacity, but higher mitochondrial function. Gene set enrichment analysis revealed enhanced c-Myc transcriptional activity in Hif1a-/- BMDMs, and upregulation of gene pathways related to ribosomal biogenesis and cellular proliferation. The findings highlight the heterogeneity of HIF-1 function in distinct macrophage populations and provide new insight into how HIF-1 regulates gene expression, inflammation, and metabolism in macrophages.

cell biology↗

bioRxiv2024

ATF4 and mTOR regulate metabolic reprogramming in TGF-β-treated lung fibroblasts

Idiopathic pulmonary fibrosis is a fatal disease characterized by the TGF-{beta}-dependent activation of lung fibroblasts, leading to excessive deposition of collagen proteins and progressive replacement of healthy lung with scar tissue. We and others have shown that fibroblast activation is supported by metabolic reprogramming, including the upregulation of the de novo synthesis of glycine, the most abundant amino acid found in collagen protein. How fibroblast metabolic reprogramming is regulated downstream of TGF-{beta} is incompletely understood. We and others have shown that TGF-{beta}-mediated activation of the Mechanistic Target of Rapamycin Complex 1 (mTORC1) and downstream upregulation of Activating Transcription Factor 4 (ATF4) promote increased expression of the enzymes required for de novo glycine synthesis; however, whether mTOR and ATF4 regulate other metabolic pathways in lung fibroblasts has not been explored. Here, we used RNA sequencing to determine how both ATF4 and mTOR regulate gene expression in human lung fibroblasts following TGF-{beta}. We found that ATF4 primarily regulates enzymes and transporters involved in amino acid homeostasis as well as aminoacyl-tRNA synthetases. mTOR inhibition resulted not only in the loss of ATF4 target gene expression, but also in the reduced expression of glycolytic enzymes and mitochondrial electron transport chain subunits. Analysis of TGF-{beta}-induced changes in cellular metabolite levels confirmed that ATF4 regulates amino acid homeostasis in lung fibroblasts while mTOR also regulates glycolytic and TCA cycle metabolites. We further analyzed publicly available single cell RNAseq data sets and found increased expression of ATF4 and mTOR metabolic targets in pathologic fibroblast populations from the lungs of IPF patients. Our results provide insight into the mechanisms of metabolic reprogramming in lung fibroblasts and highlight novel ATF4 and mTOR-dependent pathways that may be targeted to inhibit fibrotic processes.

cell biology↗

bioRxiv2023

Mitochondrial One-Carbon Metabolism is Required for TGF-β-Induced Glycine Synthesis and Collagen Protein Production

A hallmark of Idiopathic Pulmonary Fibrosis is the TGF-{beta}-dependent activation of lung fibroblasts, leading to excessive deposition of collagen proteins and progressive scarring. We have previously shown that synthesis of collagen by lung fibroblasts requires de novo synthesis of glycine, the most abundant amino acid in collagen protein. TGF-{beta} upregulates the expression of the enzymes of the de novo serine/glycine synthesis pathway in lung fibroblasts through mTORC1 and ATF4- dependent transcriptional programs. SHMT2, the final enzyme of the de novo serine/glycine synthesis pathway, transfers a one-carbon unit from serine to tetrahydrofolate (THF), producing glycine and 5,10-methylene-THF (meTHF). meTHF is converted back to THF in the mitochondrial one-carbon (1C) pathway through the sequential actions of MTHFD2 (which converts meTHF to 10-formyl-THF), and either MTHFD1L, which produces formate, or ALDH1L2, which produces CO2. It is unknown how the mitochondrial 1C pathway contributes to glycine biosynthesis or collagen protein production in fibroblasts, or fibrosis in vivo. Here, we demonstrate that TGF-{beta} induces the expression of MTHFD2, MTHFD1L, and ALDH1L2 in human lung fibroblasts. MTHFD2 expression was required for TGF-{beta}-induced cellular glycine accumulation and collagen protein production. Combined knockdown of both MTHFD1L and ALDH1L2 also inhibited glycine accumulation and collagen protein production downstream of TGF-{beta}; however knockdown of either protein alone had no inhibitory effect, suggesting that lung fibroblasts can utilize either enzyme to regenerate THF. Pharmacologic inhibition of MTHFD2 recapitulated the effects of MTHFD2 knockdown in lung fibroblasts and ameliorated fibrotic responses after intratracheal bleomycin instillation in vivo. Our results provide insight into the metabolic requirements of lung fibroblasts and provide support for continued development of MTHFD2 inhibitors for the treatment of IPF and other fibrotic diseases.

cell biology↗

bioRxiv2022

Endogenous production of hyaluronan, PRG4, and cytokines is sensitive to cyclic loading in synoviocytes

Synovial fluid is composed of hyaluronan and proteoglycan-4 (PRG4 or lubricin), which work synergistically to maintain joint lubrication. In diseases like osteoarthritis, hyaluronan and PRG4 concentrations can be altered, resulting in lowered synovial fluid viscosity, and pro-inflammatory cytokine concentrations within the synovial fluid increase. Synovial fibroblasts within the synovium are responsible for contributing to synovial fluid and can be targeted to improve endogenous production of hyaluronan and PRG4 and to alter the cytokine profile. We cyclically loaded SW982 synoviocytes to 0%, 5%, 10%, or 20% strain for three hours at 1 Hz. To assess the impact of substrate stiffness, we compared the 0% strain group to cells grown on tissue culture plastic. We measured the expression of hyaluronan turnover genes, hyaluronan localization within the cell layer, hyaluronan concentration, PRG4 concentration, and the cytokine profile within the media. Our results show that the addition of cyclic loading increased HAS3 expression, but not in a magnitude-dependent response. Hyaluronidase expression was impacted by strain magnitude, which is exemplified by the decrease in hyaluronan concentration due to cyclic loading. We also show that PRG4 concentration is increased at 5% strain, while higher strain magnitude decreases overall PRG4 concentration. Finally, 10% and 20% strain show a distinct, more pro-inflammatory cytokine profile when compared to the unloaded group. Multivariate analysis showed distinct separation between certain strain groups in being able to predict strain group, hyaluronan concentration, and PRG4 concentration from gene expression or cytokine concentration data, highlighting the complexity of the system. Overall, this study shows that cyclic loading can be used tool to modulate the endogenous production of hyaluronan, PRG4, and cytokines from synovial fibroblasts.

bioengineering↗

bioRxiv2022

HIF-1α induces glycolytic reprogramming in tissue-resident alveolar macrophagesto promote survival during acute lung injury

Cellular metabolism is a critical regulator of macrophage effector function. Tissue-resident alveolar macrophages (TR-AMs) inhabit a unique niche marked by high oxygen and low glucose. We have recently shown that in contrast to bone marrow-derived macrophages (BMDMs), TR-AMs cannot utilize glycolysis and predominantly rely on mitochondrial function for their effector response. It is not known how changes in local oxygen concentration that occur during conditions such as acute respiratory distress syndrome (ARDS) might affect TR-AM metabolism and function; however, ARDS is associated with progressive loss of TR-AMs, which correlates with the severity of disease and mortality. Here, we demonstrate that hypoxia robustly stabilizes HIF-1 in TR-AMs to promote a glycolytic phenotype. Hypoxia altered TR-AM metabolite signatures, cytokine production, and decreased their sensitivity to the inhibition of mitochondrial function. By contrast, hypoxia had minimal effects on BMDM metabolism. The effects of hypoxia on TR-AMs were mimicked by FG-4592, a HIF-1 stabilizer. Treatment with FG-4592 decreased TR-AM death and attenuated acute lung injury in mice. These findings reveal the importance of microenvironment in determining macrophage metabolic phenotype, and highlight the therapeutic potential in targeting cellular metabolism to improve outcomes in diseases characterized by acute inflammation.

cell biology↗

bioRxiv2020

Endogenous itaconate is not required for particulate matter-induced NRF2 expression or inflammatory response

Particulate matter (PM) air pollution causing significant cardiopulmonary mortality via macrophage-driven lung inflammation; however, the mechanisms are not completely understood. RNA-sequencing demonstrated Acod1 (Aconitate decarboxylase 1) as one of the top genes induced by PM in macrophages. Acod1 encodes a mitochondrial enzyme that produces itaconate, which has been shown to exert anti-inflammatory effects via NRF2 after LPS. Here, we demonstrate that PM induces Acod1 and itaconate, which reduced mitochondrial respiration via complex II inhibition. Using Acod1-/- macrophages, we found that Acod1/endogenous itaconate was not required for PM-induced inflammation or NRF2 activation. In contrast to endogenous itaconate, exogenous cell permeable form of itaconate (4-octyl itaconate (OI)) attenuated the PM-induced inflammation and activated NRF2 but NRF2 was not required for the anti-inflammatory effects of OI. We conclude that the effects of itaconate production on inflammation are stimulus-dependent, and that there are important differences between endogenous and exogenously-applied itaconate.

cell biology↗