Biology subjects

Blake, M.

Publications and source records attributed to Blake, M..

10 recordsLinked to original sources

bioRxiv2026

Multi-Omic Profiling Defines the Renal Mechanisms of Cardiovascular-Kidney-Metabolic Syndrome in Pulmonary Arterial Hypertension

Background: Cardiovascular-kidney-metabolic (CKM) syndrome integrates cardiac, renal, and metabolic abnormalities that drive multi-organ injury. In pulmonary arterial hypertension (PAH), CKM manifests as systemic metabolic derangements, right ventricular dysfunction, and renal compromise. Renal dysfunction strongly predicts mortality in PAH, yet current therapies provide little renal benefit. Moreover, the mechanisms driving PAH nephropathy remain poorly understood, limiting our ability to effectively treat PAH-CKM. Methods: Single-nucleus RNA sequencing identified cell-type-specific transcriptional alterations in autopsy-derived kidneys from control (n=5) and PAH (n=4) patients. Mitochondrial, cytoplasmic, and phosphoproteomic analyses profiled proteomic alterations. AlphaFold 3/ChimeraX modeling defined the predicted structural consequences of altered protein phosphorylation. Histological analysis assessed renal fibrosis, glomerular structure, immune cell infiltration, and nephron segment density. Results: 3 of 4 PAH patients exhibited renal impairment, with a cohort mean estimated glomerular filtration rate of 61 plus or minus 36 mL/min/1.73m squared. snRNA-seq identified a distinct cellular architecture in PAH kidneys, marked by an increase in thick ascending limb, proximal tubule, and immune cell nuclei and depletion of collecting duct nuclei. Transcriptional profiling demonstrated proximal tubule and thick ascending limb cells both upregulated fatty acid oxidation, ferroptosis, and cuproptosis pathways. PAH lymphocytes displayed heightened T87 cell receptor signaling, natural killer cell-mediated cytotoxicity, and Th17 differentiation. Histological analyses demonstrated increased perivascular fibrosis, glomerular T-cell infiltration, and a reduction in glomerular basement membrane density in PAH kidneys. Mitochondrial and cytoplasmic proteomics revealed broad metabolic dysfunction characterized by impaired {beta}-oxidation, TCA cycle activity, amino acid metabolism, transsulfuration, and urea cycle pathways. Phosphoproteomics predicted increased GSK3{beta}, STK, and casein kinase activity in PAH kidneys. Finally, using the totality of our data, we nominated multiple druggable targets that could be evaluated to counteract PAH nephropathy. Conclusions: Integrated multi-omic profiling demonstrates PAH nephropathy is defined by glomerular structural remodeling, proximal nephron ferroptotic and cuproptotic signaling, amino acid metabolic dysregulation, and innate and adaptive leukocyte activation. Future studies intervening on these pathways could lead to the development of novel therapeutics to augment renal function in PAH.

molecular biology↗

bioRxiv2026

Pulmonary Arterial Hypertension Induces a Metabolic and Inflammatory Hepatopathy

Right ventricular failure (RVF) is a robust predictor of mortality in pulmonary arterial hypertension (PAH); however, the mechanisms linking RVF to end-organ dysfunction remain unclear. Hepatic impairments portend poor outcomes in PAH, but the cell-specific effects of PAH on the human liver are unknown. Here, we performed single nucleus RNA sequencing on autopsy-derived liver tissue from five PAH patients and four non-PAH controls and compared these findings to non-alcoholic steatohepatitis (NASH) and Fontan-associated liver disease (FALD). PAH hepatocytes were characterized by a pro-proliferative, Warburg-like metabolic phenotype. PAH endothelial cells (ECs) also adopted a Warburg-like profile. Although EC PI3K-Akt activation was present in PAH and FALD ECs, only PAH ECs demonstrated impaired adhesion/barrier signaling. In PAH hepatic stellate cells (HSCs), PI3K-Akt signaling was enriched, while NASH and FALD HSCs co-activated PI3K-Akt and TGF-{beta}. Activated HSC abundances were increased in PAH livers and associated with heightened central vein fibrosis. PAH and NASH macrophages showed elevated complement signaling but reduced JAK-STAT activity. PAH livers exhibited dysregulated vasoactive gene expression, increased interleukin-6 expression in HSCs, and suppressed hepatocyte ketone metabolism. Correlational analysis demonstrated that HSC HIF-1 activation was associated with PAH severity. In total, these findings define the metabolic and inflammatory hepatopathy of PAH.

biochemistry↗

bioRxiv2025

Impaired Lung BCAA Metabolism Promotes Ferroptosis and Resultant Pulmonary Arterial Hypertension-Associated Hepatopathy

BackgroundDysregulated branched chain amino acid (BCAA) homeostasis occurs in pulmonary arterial hypertension (PAH) as BCAA metabolites accumulate and cause metabolic alterations in pulmonary artery smooth muscle cells (PASMC). In other cells, altered BCAA metabolism promotes ferroptosis, a PAH-inducing metabolic pathway. However, the interplay between BCAAs, lung ferroptosis, and PAH is unexplored, as is the impact of PAH severity on liver molecular regulation, a key unknown as recent clinical data highlight the importance of the lung-right heart-liver axis in PAH outcomes. MethodsHuman metabolomic and transcriptomic studies examined BCAA metabolism and ferroptosis pathways. The relationship between BCAAs and ferroptotic-phenotypes in PASMCs was evaluated. Multi-omics and physiological analyses evaluated how modulation of BCAA catabolism impacted preclinical PAH multi-organ physiology. Confocal microscopy and proteomic analyses assessed hepatic alterations in human PAH. ResultsMetabolomic analyses identified alterations in BCAA metabolites across multiple physiological gradients in patients with pulmonary vascular disease. RNA sequencing demonstrated deficits in the BCAA catabolic and ferroptosis pathways in PAH lungs and smooth muscle cells. In vitro, excess BCAAs induced mitochondrial fragmentation, reactive oxygen species generation, and lipid peroxidation in PASMC. Moreover, BCAAs promoted PASMC death, which ferrostatin-1, a ferroptosis antagonist, rescued. BT2, a small-molecule inducer of BCAA catabolism, reduced PAH severity, improved RV function, and enhanced maximal exercise capacity in monocrotaline rats. BT2 blunted pro-ferroptotic changes in lung metabolites and proteins, and combatted peri-vascular complement deposition. In the liver, BT2 blocked mechanical shear stress phenotypes including hepatocyte nuclear expansion and restructured mitochondrial protein regulation and the metabolomic signature. Additionally, a low BCAA diet modestly combatted preclinical PAH severity. Finally, human PAH livers exhibited increased hepatocyte nuclear size and derangements in liver metabolic regulation. ConclusionsImpaired BCAA metabolism promotes PAH via ferroptosis. PAH severity is associated with hepatic pathological shear stress phenotypes and metabolic alterations, which are combatted by a BCAA-targeted therapy. Graphical Abstract/Summary Figure O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/672819v1_ufig1.gif" ALT="Figure 1"> View larger version (55K): org.highwire.dtl.DTLVardef@1649980org.highwire.dtl.DTLVardef@199c40aorg.highwire.dtl.DTLVardef@1586fdorg.highwire.dtl.DTLVardef@15166c1_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2024

In silico analysis of the evolution of root phenotypes during maize domestication in Neolithic soils of Tehuacan

Roots are essential for plant adaptation to changing environments, yet the role of roots in crop domestication remains unclear. This study examines the evolution of root phenotypes from teosinte to maize, a transition resulting in reduced nodal root number (NRN), multiseriate cortical sclerenchyma (MCS), and increased seminal root number (SRN). We reconstructed the root phenotypes of maize and teosinte, as well as the environments of the Tehuacan Valley over the last 18,000 years using a combination of ancient DNA, paleobotany, and functional-structural modeling. Our models reveal that increasing Holocene atmospheric CO2 concentrations favored the appearance of reduced NRN and MCS between 12000 to 8000 years before present (yBP), promoting deeper root systems. The advent of irrigation by 6000 yBP switched nitrogen distribution from topsoil to subsoil domains, a change which increased the utility of reduced NRN and MCS. Comparison of allelic frequencies among ancient samples ranging from 5500 to 500 yBP suggest that increased SRN may have appeared around 3500 yBP, coinciding with a period of increased human population, agricultural intensification, and soil degradation. Our results suggest that root phenotypes that enhance plant performance under nitrogen stress were important for maize adaptation to changing agricultural practices in the Tehuacan Valley. ClassificationPhysiology & Development

plant biology↗

bioRxiv2024

Lactobacillus Restructures the Micro/Mycobiome to Combat Glycoprotein-130 Associated Microtubule Remodeling and Right Ventricular Dysfunction in Pulmonary Arterial Hypertension

Emerging data demonstrate systemic and local inflammation regulate right ventricular (RV) adaption in preclinical and human pulmonary arterial hypertension (PAH). Pathological RV inflammation is targetable as antagonism of glycoprotein-130 (GP130) signaling counteracts pathological microtubule remodeling and improves RV function in rodents. Microtubules control several aspects of cardiomyocyte biology including cellular and nuclear size/structure, t-tubule homeostasis, and the proper localization of connexin-43. The intestinal microbiome regulates systemic inflammation, but the impact of the gut microbiome on the GP130-microtubule axis in RV failure is unknown. Here, we examined how the anti-inflammatory bacteria, Lactobacillus, modulated cellular and physiological RV phenotypes in preclinical and clinical PAH. Lactobacillus supplementation restructured the gut micro/mycobiome, suppressed systemic inflammation, combatted pathological GP130-mediated RV cardiomyocyte microtubule remodeling, and augmented RV function in rodent PAH. Moreover, Lactobacillus was associated with superior RV adaption in human PAH. These data further support the hypothesis that inflammation negatively impacts RV adaption in PAH, and identify the gut microbiome as a potentially targetable regulator of RV function in PAH.

physiology↗

bioRxiv2023

VTA dopamine neurons drive spatiotemporally heterogeneous striatal dopamine signals during learning

Environmental cues, through Pavlovian learning, become conditioned stimuli that invigorate and guide animals toward acquisition of rewards. Dopamine neurons in the ventral tegmental area (VTA) and substantia nigra (SNC) are crucial for this process. Dopamine neurons are embedded in a reciprocally connected network with their striatal targets, the functional organization of which remains poorly understood. Here, we investigated how learning during optogenetic Pavlovian cue conditioning of VTA or SNC dopamine neurons directs cue-evoked behavior and shapes subregion-specific striatal dopamine dynamics. We used a fluorescent dopamine biosensor to monitor dopamine in the nucleus accumbens (NAc) core and shell, dorsomedial striatum (DMS), and dorsolateral striatum (DLS). We demonstrate spatially heterogeneous, learning-dependent dopamine changes across striatal regions. While VTA stimulation evoked robust dopamine release in NAc core, shell, and DMS, cues predictive of this activation preferentially recruited dopamine release in NAc core, starting early in training, and DMS, late in training. Corresponding negative prediction error signals, reflecting a violation in the expectation of dopamine neuron activation, only emerged in the NAc core and DMS, and not the shell. Despite development of vigorous movement late in training, conditioned dopamine signals did not similarly emerge in the DLS, even during Pavlovian conditioning with SNC dopamine neuron activation, which elicited robust DLS dopamine release. Together, our studies show broad dissociation in the fundamental prediction and reward-related information generated by different dopamine neuron populations and signaled by dopamine across the striatum. Further, they offer new insight into how larger-scale plasticity across the striatal network emerges during Pavlovian learning to coordinate behavior.

neuroscience↗

bioRxiv2023

Ketone bodies in Right Ventricular Failure: A Unique Therapeutic Opportunity

Introductory ParagraphKetone bodies are pleotropic metabolites that play important roles in multiple biological processes ranging from bioenergetics to inflammation regulation via suppression of the NLRP3 inflammasome, and epigenetic modifications. Ketone bodies are elevated in left ventricular failure (LVF) and multiple approaches that increase ketone concentrations exert advantageous cardiac effects in rodents and humans. However, the relationships between ketone bodies and right ventricular failure (RVF) are relatively unexplored. Moreover, the cardioprotective properties of ketones in preclinical RVF are unknown. Here, we show a compensatory ketosis is absent in pulmonary arterial hypertension (PAH) patients with RVF. In the monocrotaline (MCT) rat model of PAH-mediated RVF, a dietary-induced ketosis improves RV function, suppresses NLRP3 inflammasome activation, and combats RV fibrosis. The summation of these data suggest ketogenic therapies may be particularly efficacious in RVF, and therefore future studies evaluating ketogenic interventions in human RVF are warranted.

biochemistry↗

bioRxiv2021

Understanding Others Requires Right Temporoparietal and Inferior Frontal Regions

The human ability to infer other peoples knowledge and beliefs, known as theory of mind, is an essential component of social interactions. Theory of mind tasks activate frontal and temporoparietal regions of cortex in fMRI studies. However, it is unknown whether these regions are critical. We examined this question using multivariate voxel-based lesion symptom mapping in 22 patients with acute right hemisphere brain damage. Studies of acute patients eliminate questions of recovery and reorganization that plague long-term studies of lesioned patients. Damage to temporoparietal and inferior frontal regions impaired thinking about others perspectives. This impairment held even after adjustment for overall extent of brain damage and language comprehension, memory, comprehension, and attention abilities. These results provide evidence that right temporoparietal and inferior frontal regions are necessary for the human ability to reason about the knowledge and beliefs of others.

neuroscience↗

bioRxiv2020

Cognitive deficits found in a pro-inflammatory state are independent of ERK 1/2 signaling in the murine brain hippocampus treated with Shiga toxin 2 from enterohemorrhagic Escherichia Coli

Shiga toxin 2 (Stx2) from enterohemorrhagic Escherichia coli (EHEC) produces hemorrhagic colitis, hemolytic uremic syndrome (HUS) and acute encephalopathy. The mortality rate in HUS increases significantly when the central nervous system (CNS) is involved. Besides, EHEC also releases lipopolysaccharide (LPS). Many reports have described cognitive dysfunctions in HUS patients, the hippocampus being one of the brain areas targeted by EHEC infection. In this context, a translational murine model of encephalopathy was employed to establish the deleterious effects of Stx2 and the contribution of LPS in the hippocampus. Results demonstrate that systemic administration of a sublethal dose of Stx2 reduced memory index and produced depression like behavior, pro-inflammatory cytokine release and NF-kB activation independent of the ERK 1/2 signaling pathway. On the other hand, LPS activated NF-kB dependent on ERK 1/2 signaling pathway. Cotreatment of Stx2 with LPS aggravated the pathologic state, while dexamethasone treatment succeeded in preventing behavioral alterations. Our present work suggests that the use of drugs such as corticosteroids or NF-kB signaling inhibitors may serve as neuroprotectors from EHEC infection.

pathology↗

bioRxiv2019

Inhibition of the Myocardin-Related Transcription Factor pathway increases efficacy of Trametinib in NRAS-mutant melanoma cell lines

The Ras/MEK/ERK pathway has been the primary focus of targeted therapies in melanoma; it is aberrantly activated in almost 80% of human cutaneous melanomas ([~]50% BRAFV600 mutations and [~]30% NRAS mutations). While targeted therapies have yielded success in BRAFV600 mutant melanoma patients, such therapies have been ineffective in NRAS mutant melanomas in part due to their cytostatic effects and primary resistance in this patient population. Here, we demonstrate that increased Rho/MRTF-pathway activation correlates with high intrinsic resistance to the MEK inhibitor, trametinib, in a panel of NRAS mutant melanoma cell lines. Combination of trametinib with the Rho/MRTF-pathway inhibitor, CCG-222740, synergistically reduced cell viability in NRAS mutant melanoma cell lines in vitro. Furthermore, the combination of CCG-222740 with trametinib induced apoptosis and reduced clonogenicity in SK-Mel-147 cells which have a high level of trametinib resistance. These findings suggest a role of the Rho/MRTF-pathway in intrinsic trametinib resistance in a subset of NRAS mutant melanoma cell lines and highlights the potential of concurrently targeting the Rho/MRTF-pathway and MEK in NRAS mutant melanomas.

cancer biology↗