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Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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Selective PPAR-α activation with pemafibrate attenuates macrophage-mediated progression of calcific aortic valve disease

BACKGROUNDCalcific aortic valve disease (CAVD) compromises valve compliance and cardiac hemodynamics leading to aortic stenosis (AS) and cardiovascular dysfunction. With treatment for severe AS limited to valve replacement and no effective pharmacotherapies, new interventions are urgently needed for patients. This study evaluated pemafibrate, a selective peroxisome proliferator-activated receptor alpha (PPAR) activator as a novel therapeutic for CAVD and AS. METHODS AND RESULTSIn an aortic valve wire injury (AVWI) model of AS in Ldlr-/- mice, pemafibrate administration (0.2 mg/kg/day) for 15 weeks improved aortic valve function and reduced valvular calcification by 39% (p<0.001), accompanied by reduced leaflet inflammation and CD68 macrophage infiltration. These effects were independent of changes in plasma triglyceride levels. In vitro, pemafibrate suppressed inflammation-mediated calcification of primary human valvular interstitial cells (VICs) by modulating macrophage-derived secreted factors, identifying macrophage-VIC crosstalk as a key disease mechanism. Direct treatment of macrophages with pemafibrate, or exposure to serum from pemafibrate-treated participants in the PROMINENT randomized controlled trial, shifted macrophages toward a less inflammatory and less chemotactic phenotype. Proteomic analyses of patient serum substantiated these findings by reflecting a systemic reduction in inflammatory parameters and monocyte activation. Network integration of the in vitro derived pemafibrate-responsive proteome with human calcified AV tissue proteomes identified aberrant protein translation (GNB2L1, GSPT1) and disrupted bioenergetics (MYDGF, PDIA4) as potential clinically relevant pemafibrate-responsive pathways and effector proteins relevant to AS progression. CONCLUSIONSPemafibrate slows experimental AS progression and valve calcification through modulation of macrophage-VIC crosstalk, independent of lipid lowering. These findings support further evaluation of pemafibrate as a potential pharmacological approach for CAVD and support further testing in randomized clinical trials.

pharmacology and toxicology↗

Tissue specificity of in vitro drug sensitivity

Research in oncology traditionally focuses on specific tissue type from which the cancer develops. However, advances in high-throughput molecular profiling technologies have enabled the comprehensive characterization of molecular aberrations in multiple cancer types. It was hoped that these large-scale datasets would provide the foundation for a paradigm shift in oncology which would see tumors being classified by their molecular profiles rather than tissue types, but tumors with similar genomic aberrations may respond differently to targeted therapies depending on their tissue of origin. There is therefore a need to reassess the potential association between pharmacological response and tissue of origin for therapeutic drugs, and to test how these associations translate from preclinical to clinical settings.\n\nIn this paper, we investigate the tissue specificity of drug sensitivities in large-scale pharmacological studies and compare these associations to those found in clinical trial descriptions. Our meta-analysis of the four largest in vitro drug screening datasets indicates that tissue of origin is strongly associated with drug response. We identify novel tissue-drug associations, which may present exciting new avenues for drug repurposing. One caveat is that the vast majority of the significant associations found in preclinical settings do not concur with clinical observations. Accordingly, our results call for more testing to find the root cause of the discrepancies between preclinical and clinical observations.

bioinformatics↗

Hydroxychloroquine Proves Ineffective in Hamsters and Macaques Infected with SARS-CoV-2

We remain largely without effective prophylactic/therapeutic interventions for COVID-19. Although many human clinical trials are ongoing, there remains a deficiency of supportive preclinical drug efficacy studies. Here we assessed the prophylactic/therapeutic efficacy of hydroxychloroquine (HCQ), a drug of interest for COVID-19 management, in two animal models. When used for prophylaxis or treatment neither the standard human malaria dose (6.5 mg/kg) nor a high dose (50 mg/kg) of HCQ had any beneficial effect on clinical disease or SARS-CoV-2 kinetics (replication/shedding) in the Syrian hamster disease model. Similarly, HCQ prophylaxis/treatment (6.5 mg/kg) did not significantly benefit clinical outcome nor reduce SARS-CoV-2 replication/shedding in the upper and lower respiratory tract in the rhesus macaque disease model. In conclusion, our preclinical animal studies do not support the use of HCQ in prophylaxis/treatment of COVID-19.One Sentence Summary Hydroxychloroquine prophylaxis/treatment showed no beneficial effect in SARS-CoV-2 hamster and macaque disease models.Competing Interest StatementThe authors have declared no competing interest.View Full Text

pharmacology and toxicology↗

Utilisation of semiconductor sequencing for detection of actionable fusions in solid tumors

Oncogenic fusions represent compelling druggable targets in solid tumours highlighted by the recent site agnostic FDA approval of larotrectinib for NTRK rearrangements. However screening for fusions in routinely processed tissue samples is constrained due to degradation of nucleic acid as a result of formalin fixation., To investigate the clinical utility of semiconductor sequencing optimised for detection of actionable fusion transcripts in formalin fixed samples, we have undertaken an analysis of test trending data generated by a clinically validated next generation sequencing platform designed to capture 867 of the most clinically relevant druggable driver-partner oncogenic fusions. Here we showacross a real-life cohort of 1112 patients with solid tumours that actionable fusions occur at high frequency (7.4%) with linkage to a wide range of targeted therapy protocols including seven fusion-drug matches with FDA/EMA approval and/or NCCN/ESMO recommendations and 80 clinical trials. The majority of actionable fusions identified were independent of tumour type in keeping with signalling via evolutionary conserved Wnt/{beta}-catenin, RAS/RAF/MEK/ERK, PI3K/AKT/MTOR, PLCy/PKC and JAK/STAT pathways. Taken together our data indicates that semiconductor sequencing for detection of actionable fusions can be integrated into routine diagnostic pathology workflows enabling the identification of personalised treatment options that have potential to improve clinical cancer management across many tumour types.

cancer biology↗

Cystinosin deficient rats recapitulate the phenotype of nephropathic cystinosis

BackgroundThe lysosomal storage disease cystinosis is caused by mutations in CTNS, encoding a cystine transporter, and in its severest form leads to proximal tubule dysfunction followed by kidney failure. Patients receive the drug-based therapy cysteamine from diagnosis. However, despite long-term treatment, cysteamine only slows the progression of end-stage renal disease and a kidney transplant is inevitable. Pre-clinical testing in cystinotic rodents is required to evaluate new therapies; however, the current models are sub-optimal. To solve this problem we generated a new cystinotic rat model. MethodsWe utilized CRISPR/Cas9-mediated gene editing to disrupt exon 3 of Ctns and measured various parameters over a 12-month time-course including blood and tissue cystine levels, urine and serum electrolytes, and analysed the histopathology and immunohistochemistry of the kidney. ResultsCtns-/- rats display hallmarks of cystinosis by 3-6 months of age as seen by a failure to thrive, excessive thirst and urination, cystine accumulation in tissues, corneal cystine crystals, a loss of Lrp2 in proximal tubules and immune cell infiltration. High levels of glucose, calcium, albumin and protein are excreted at 6-months of age, consistent with the onset of Fanconi syndrome, with a progressive diminution of urine urea and creatinine from 9-months of age, indicative of chronic kidney disease. The kidney histology and immunohistochemistry showed proximal tubule atrophy and glomerular damage as well as classic swan neck lesions. Overall, Ctns-/- rats show a disease progression that more faithfully recapitulates nephropathic cystinosis than existing rodent models. ConclusionsThe Ctns-/- rat provides an excellent new rodent model of nephropathic cystinosis that is ideally suited for conducting pre-clinical drug testing and a powerful tool to advance cystinosis research. Translational StatementGood animal models of disease are essential to perform pre-clinical testing of potential new drugs and therapies before they can progress to human clinical trials. Unfortunately, the cystinosis field has been hampered by a lack of suitable animal models that fully recapitulate the disease. We have overcome this by generating a new rat model of cystinosis by CRISPR-Cas9 gene editing. These rodents closely model the human condition in a time-frame that makes them an excellent model ideally suited for pre-clinical drug testing as well as being a powerful tool to advance cystinosis research.

physiology↗

Psilocybin prevents activity-based anorexia in female rats by enhancing cognitive flexibility: contributions from 5-HT1A and 5-HT2A receptor mechanisms.

Psilocybin has shown promise for alleviating symptoms of depression and is currently in clinical trials for the treatment of anorexia nervosa (AN), a condition that is characterised by persistent cognitive inflexibility. Considering that enhanced cognitive flexibility after psilocybin treatment is reported to occur in individuals with depression, it is plausible that psilocybin could improve symptoms of AN by breaking down cognitive inflexibility. A mechanistic understanding of the actions of psilocybin is required to tailor the clinical application of psilocybin to individuals most likely to respond with positive outcomes. This can only be achieved using incisive neurobiological approaches in animal models. Here, we use the activity-based anorexia (ABA) rat model and comprehensively assess aspects of reinforcement learning to show that psilocybin (post-acutely) improves body weight maintenance in female rats and facilitates cognitive flexibility, specifically via improved adaptation to the initial reversal of reward contingencies. Further, we reveal the involvement of signalling through the serotonin (5-HT) 1A and 5-HT2A receptor subtypes in specific aspects of learning, demonstrating that 5-HT1A antagonism negates the cognitive enhancing effects of psilocybin. Moreover, we show that psilocybin elicits a transient increase and decrease in cortical transcription of these receptors (Htr2a and Htr1a, respectively), and a further reduction in the abundance of Htr2a transcripts in rats exposed to the ABA model. Together, these findings support the hypothesis that psilocybin could ameliorate cognitive inflexibility in the context of AN and highlight a need to better understand the therapeutic mechanisms independent of 5-HT2A receptor binding.

neuroscience↗

Predicting resistance of clinical Abl mutations to targeted kinase inhibitors using alchemical free-energy calculations

The therapeutic effect of targeted kinase inhibitors can be significantly reduced by intrinsic or acquired resistance mutations that modulate the affinity of the drug for the kinase. In cancer, the majority of missense mutations are rare, making it difficult to predict their impact on inhibitor affinity. This complicates the practice of precision medicine, pairing of patients with clinical trials, and development of next-generation inhibitors. Here, we examine the potential for alchemical free-energy calculations to predict how kinase mutations modulate inhibitor affinities to Abl, a major target in chronic myelogenous leukemia (CML). We find these calculations can achieve useful accuracy in predicting resistance for a set of eight FDA-approved kinase inhibitors across 144 clinically-identified point mutations, achieving a root mean square error in binding free energy changes of [Formula] kcal/mol (95% confidence interval) and correctly classifying mutations as resistant or susceptible with [Formula] accuracy. Since these calculations are fast on modern GPUs, this benchmark establishes the potential for physical modeling to collaboratively support the rapid assessment and anticipation of the potential for patient mutations to affect drug potency in clinical applications.

cancer biology↗

Response to anti-angiogenic therapy is affected by AIMP protein family activity in glioblastoma and lower-grade gliomas

BackgroundGlioblastoma (GBM) is a highly vascularized, heterogeneous tumor, yet anti-angiogenic therapies have yielded limited survival benefits. The lack of validated predictive biomarkers for treatment response stratification remains a major challenge. Aminoacyl tRNA synthetase complex-interacting multicomplex proteins (AIMPs) 1/2/3 have been implicated in CNS diseases, but their roles in gliomas remain unexplored. We investigated their association with angiogenesis and their significance as predictive biomarkers for anti-angiogenic treatment response. MethodsIn this multi-cohort retrospective study we analyzed glioma samples from TCGA, CGGA, Rembrandt, Gravendeel, BELOB and REGOMA trials, and four single-cell transcriptomic datasets. Multi-omic analyses incorporated transcriptomic, epigenetic, and proteomic data. Kaplan-Meier and Cox proportional hazards models were used to assess the prognostic value of AIMPs in heterogeneous and homogeneous treatment-groups. Using single-cell transcriptomics, we explored spatial and cell-type-specific AIMP2 expression in GBM. ResultsAIMP1/2/3 expressions correlated significantly with angiogenesis across TCGA cancers. In gliomas, AIMPs were upregulated in tumor vs. normal tissues, higher- vs. lower-grade gliomas, and recurrent vs. primary tumors (p<0.05). Upon retrospective analysis of two clinical trials assessing different anti-angiogenic drugs, we found that high-AIMP2 subgroups had improved response to therapies in GBM (REGOMA: HR 4.75 [1.96-11.5], p<0.001; BELOB: HR 2.3 [1.17-4.49], p=0.015). AIMP2-cg04317940 methylation emerged as a clinically applicable stratification marker. Single-cell analysis revealed homogeneous AIMP2 expression in tumor tissues, particularly in AC-like cells, suggesting a mechanistic link to tumor angiogenesis. ConclusionsThese findings provide novel insights into the role of AIMPs in angiogenesis, offering improved patient stratification and therapeutic outcomes in recurrent GBM.

bioinformatics↗

System-wide biochemical analysis reveals ozonide antimalarials initially act by disrupting Plasmodium falciparum haemoglobin digestion

Ozonide antimalarials, OZ277 (arterolane) and OZ439 (artefenomel), are synthetic peroxide-based antimalarials with potent activity against the deadliest malaria parasite, Plasmodium falciparum. Here we used a "multi-omics" workflow, in combination with activity-based protein profiling (ABPP), to demonstrate that peroxide antimalarials initially target the haemoglobin (Hb) digestion pathway to kill malaria parasites. Time-dependent metabolomic profiling of ozonide-treated P. falciparum infected red blood cells revealed a rapid depletion of short Hb-derived peptides followed by subsequent alterations in lipid and nucleotide metabolism, while untargeted peptidomics showed accumulation of longer Hb-derived peptides. Quantitative proteomics and ABPP assays demonstrated that Hb-digesting proteases were increased in abundance and activity following treatment, respectively. The association between ozonide activity and Hb catabolism was also confirmed in a K13-mutant artemisinin resistant parasite line. To demonstrate that compromised Hb catabolism may be a primary mechanism involved in ozonide antimalarial activity, we showed that parasites forced to rely solely on Hb digestion for amino acids became hypersensitive to short ozonide exposures. Quantitative proteomics analysis also revealed parasite proteins involved in translation and the ubiquitin-proteasome system were enriched following drug treatment, suggestive of the parasite engaging a stress response to mitigate ozonide-induced damage. Taken together, these data point to a mechanism of action involving initial impairment of Hb catabolism, and indicate that the parasite regulates protein turnover to manage ozonide-induced damage. Author SummaryThe ozonides are a novel class of fully synthetic antimalarial drugs with potent activity against all parasite species that cause malaria, including the deadliest, Plasmodium falciparum. With the emergence of resistance to current frontline artemisinin-based antimalarials, new drugs are urgently needed and a clear understanding of their mechanism of action is essential so that they can be optimally deployed in the field. Here, we studied the biochemical effects of two ozonides, OZ277 (marketed in India in combination with piperaquine) and OZ439 (in Phase IIb clinical trials) in P. falciparum parasites using an untargeted multi-omics approach consisting of proteomics, peptidomics and time-dependent metabolomics, along with activity-based protease profiling. We found that the ozonides initially disrupt haemoglobin metabolism and that they likely engage the parasite proteostatic stress response. Furthermore, when the duration of ozonide exposure was extended beyond 3 hours to reflect clinically-relevant exposure periods, additional parasite biochemical pathways were perturbed. This comprehensive analysis provides new insight into the antimalarial mode of action of ozonides and provides new opportunities for interventions to enhance their antimalarial efficacy.

microbiology↗

TopBP1 biomolecular condensates: a new therapeutic target in advanced-stage colorectal cancer.

In cancer cells, ATR signaling is crucial to tolerate the intrinsically high damage levels that normally block replication fork progression. Assembly of TopBP1, a multifunctional scaffolding protein, into condensates is required to amplify ATR kinase activity to the levels needed to coordinate the DNA damage response and manage DNA replication stress. Many ATR inhibitors are tested for cancer treatment in clinical trials, but their overall effectiveness is oven compromised by the emergence of resistance and toxicities. In this proof-of-concept study, we propose to disrupt the ATR pathway by targeting TopBP1 condensation. First, we screened a molecule-based library using a previously developed optogenetic approach and identified several TopBP1 condensation inhibitors. Amongst them, AZD2858 disrupted TopBP1 assembly induced by the clinically relevant topoisomerase I inhibitor SN-38, thereby inhibiting the ATR/Chk1 signaling pathway. We found that AZD2858 exerted its effects by disrupting TopBP1 self-interaction and binding to ATR in mammalian cells, and by increasing its chromatin recruitment n cell-free Xenopus laevis egg extracts. Moreover, AZD2858 prevented S-phase checkpoint induction by SN-38, leading to increased DNA damage and apoptosis in a colorectal cancer cell line. Lastly, AZD2858 showed synergistic effect in combination with the FOLFIRI chemotherapy regimen in a spheroid model of colorectal cancer. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/612204v3_ufig1.gif" ALT="Figure 1"> View larger version (61K): org.highwire.dtl.DTLVardef@184d016org.highwire.dtl.DTLVardef@7975f4org.highwire.dtl.DTLVardef@2f22f0org.highwire.dtl.DTLVardef@9ecb11_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

Inhibition of glutaminase elicits senolysis in therapy-induced senescent melanoma cells.

The cyclin D1-Cyclin-Dependent Kinases 4 and 6 (CDK4/6) complex is crucial for the development of melanoma. We previously demonstrated that targeting CDK4/6 using small molecule inhibitors (CDK4/6i) suppresses BrafV600E melanoma growth in vitro and in vivo through induction of cellular senescence. Clinical trials investigating CDK4/6i in melanoma have not yielded successful outcomes, underscoring the necessity to enhance the therapeutic efficacy of CDK4/6i. Accumulated research has shown that while senescence initially suppresses cell proliferation, a prolonged state of senescence eventually leads to tumor relapse by altering the tumor microenvironment, suggesting that removal of those senescent cells (in a process referred to as senolysis) is of clinical necessity to facilitate clinical response. We demonstrate that glutaminase 1 (GLS1) expression is specifically upregulated in CDK4/6i-induced senescent BrafV600E melanoma cells. Upregulated GLS1 expression renders BrafV600E melanoma senescent cells vulnerable to GLS1 inhibitor (GLS1i). Furthermore, we demonstrate that this senolytic approach targeting upregulated GLS1 expression is applicable even though those cells developed resistance to the BrafV600E inhibitor vemurafenib, a frequently encountered substantial clinical challenge to treating patients. Thus, this novel senolytic approach may revolutionize current CDK4/6i mediated melanoma treatment if melanoma cells undergo senescence prior to developing resistance to CDK4/6i. Given that we demonstrate that a low dose of vemurafenib induced senescence, which renders BrafV600E melanoma cells susceptible to GLS1i and recent accumulated research shows many cancer cells undergo senescence in response to chemotherapy, radiation, and immunotherapy, this senolytic therapy approach may prove applicable to a wide range of cancer types once senescence and GLS1 expression are induced. Key pointsUpregulated GLS1 expression renders senescent BrafV600E melanoma cells induced by CDK4/6 inhibitor (CDK4/6i) or vemurafenib susceptible to GLS1 inhibitor (GLS1i) even with BrafV600E inhibitor resistance. This senolytic therapy combining CDK4/6i and GLS1i provides insights into potential novel therapeutic strategies for metastatic melanoma and may be applicable to various types of cancers providing alternative therapy options.

cancer biology↗

Intravenous gene therapy improves lifespan and clinical outcomes in feline Sandhoff Disease

Sandhoff Disease (SD), a fatal neurodegenerative disorder, is caused by the absence of {beta}-hexosaminidase (Hex) and subsequent accumulation of GM2 ganglioside in lysosomes. Previous studies have led to adeno-associated virus (AAV) gene therapy for children with GM2 gangliosidosis in both expanded access and Phase I/II clinical trials via intracranial and/or cerebrospinal fluid-based delivery. The current study investigated intravenous (IV) gene therapy of SD cats, treated at one month of age with a bicistronic AAV vector. While untreated SD cats lived to 4.3{+/-}0.2 months, cats treated with low and high doses lived to 8.3{+/-}1.2 and 12.4{+/-}2.7 months, respectively. In-life assessments revealed clear clinical benefit of AAV treatment, with the most dramatic improvement seen in the reduction of overt full-body tremors. Cerebrospinal fluid levels of aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were decreased, indicating a reduction of cell damage within the central nervous system. Magnetic resonance imaging (MRI) and spectroscopy (MRS) acquired on a 7 Tesla scanner indicated that structural pathology and metabolite abnormalities are partially normalized by AAV treatment. Dose-dependent reduction of GM2 ganglioside storage and increases in Hex activity were most substantial in the caudal regions of the brain and in the spinal cord. Immunohistochemistry revealed reduction in neuroinflammatory cell populations and partial correction of myelin deficits. These results support the dose-dependent efficacy of AAV delivered IV for significant restoration of clinical metrics and Hex function in a feline model of SD. One Sentence SummaryIntravenous administration of AAV gene therapy is safe and efficacious in a feline model of Sandhoff disease.

pathology↗

Convergent evolution of resistance pathways during early stage breast cancer treatment with combination cell cycle (CDK) and endocrine inhibitors

Combining cyclin-dependent kinase (CDK) inhibitors with endocrine therapy improves outcomes for metastatic estrogen receptor positive (ER+), HER2 negative, breast cancer patients. However, the value of this combination in potentially curable earlier stage patients is not clear. Using single cell transcriptomic profiling, we examined the evolutionary trajectories of early stage breast cancer tumors using serial tumor biopsies from a clinical trial of preoperative endocrine therapy (letrozole) alone or in combination with the cell cycle inhibitor ribociclib. Applying hierarchical regression and Gaussian process mathematical modelling, we classified each tumor by whether it shrinks or persists with therapy and determined cancer phenotypes related to evolution of resistance and cell cycle transcriptional rewiring. We found that all patients tumors undergo subclonal evolution during therapy, irrespective of the clinical response. However, tumors subjected to endocrine therapy alone showed reduced diversity over time, while those facing combination therapy exhibited increased diversity. Despite different subclonal diversity, single nuclei RNA sequencing uncovered common phenotypic changes in tumor cells that persist following treatment. In these tumors, cancer cells with accelerated loss of estrogen signaling have convergent up-regulation of the JNK pathway, while cells that maintain estrogen signaling during therapy show potentiation of CDK4/6 activation consistent with ERBB4 and ERK signaling up-regulation. These convergent phenotypes were associated with growing tumors resistant to combination therapy. Cell cycle reconstruction identified that these tumors can rebound during combination therapy treatment, indicating stronger selection and promotion of a proliferative state. These results indicate that combination therapy in early stage ER+ breast cancers with ER and CDK inhibition drives rapid evolution of resistance via a shift from estrogen signaling to alternative growth factor receptor mediated proliferation and JNK signaling activation, concordant with a bypass in the G1 checkpoint.

cancer biology↗

Assessment of The Broad-Spectrum Host Targeting Antiviral Efficacy of Halofuginone Hydrobromide in Human Airway, Intestinal and Brain Organoid Models.

Halofuginone hydrobromide has shown potent antiviral efficacy against a variety of viruses such as SARS-CoV-2, dengue, or chikungunya virus, and has, therefore, been hypothesized to have broad-spectrum antiviral activity. In this paper, we tested this broad-spectrum antiviral activity of Halofuginone hydrobomide against viruses from different families (Picornaviridae, Herpesviridae, Orthomyxoviridae, Coronaviridae, and Flaviviridae). To this end, we used relevant human models of the airway and intestinal epithelium and regionalised neural organoids. Halofuginone hydrobomide showed antiviral activity against SARS-CoV-2 in the airway epithelium with no toxicity at equivalent concentrations used in human clinical trials but not against any of the other tested viruses. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=199 HEIGHT=200 SRC="FIGDIR/small/565121v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@10d562eorg.highwire.dtl.DTLVardef@94f903org.highwire.dtl.DTLVardef@683b6forg.highwire.dtl.DTLVardef@11620ba_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIHalofuginone hydrobromide was identified as a possible broad-spectrum host targeting antiviral drug. C_LIO_LIHuman organoid models offer a physiologically relevant and clinically translatable model for antiviral research. C_LIO_LIHalofuginone hydrobromide shows antiviral efficacy against SARS-CoV-2, but not against EV-A71, PeV-A1, IAV, RV-A16, HCMV or ZIKV in relevant organoid models. C_LIO_LIThe efficacy of Halofuginone hydrobromide is concentration dependent as well as on proline content of the host receptor(s) or host factors for the specific virus in question. C_LI

microbiology↗

Taxonomy-free fecal microbiome profiles enable robust prediction of immunotherapy response and toxicity in melanoma

The gut microbiome has been causally linked to the efficacy of immune-checkpoint inhibitor therapy (ICI), prompting numerous clinical trials of microbiome-targeting strategies. Yet, mechanisms by which gut microbiota shape immune responses remain elusive as taxonomic biomarkers have failed to generalize across multiple cohorts. In this study, we develop a taxonomy-agnostic framework to identify microbial biomarkers of ICI response and immune-related adverse event (irAE) occurrence from metagenomic sequencing. Applying this approach to four independent melanoma cohorts from clinical centers across the United States, we uncover gut microbial proteins produced by diverse bacterial taxa that consistently predict ICI response. Notably, we uncover a previously uncharacterized operon involved in cellular redox homeostasis that is encoded by different bacteria and reliably predicts irAE occurrence. We further validated the predictive power of this operon in a prospectively sequenced melanoma cohort. Our results demonstrate that taxa-agnostic microbial protein biomarkers are robust, generalizable, and provide a path towards pretreatment risk stratification for melanoma patients initiating ICI therapy.

cancer biology↗

Foundation models for linking brain functional representations and clinical outcomes across local intervention studies targeting cognitive aging: Validity and generalizability

The benefits of interventions targeting cognitive aging vary substantially across individuals, largely owing to heterogeneity in aging-related comorbidities. It is necessary to robustly identify neural patterns underlying intervention response and test their generalizability across heterogeneous cohorts. Resting-state functional MRI (rsfMRI) offers a potential pathway, but relying on predefined summary features with conventional methods has limited capacity to capture both within-individual longitudinal variation and between-individual differences, particularly in small and heterogeneous studies. Recent rsfMRI foundation models pretrained on large observational cohorts present a promising alternative by learning transferable spatiotemporal representations from time-series signals. Yet their validity and generalizability in local intervention settings remain unclear. Here, we systematically evaluated rsfMRI foundation models using data from two independent randomized controlled trials of older adults with mild cognitive impairment, testing whether these models can robustly extract longitudinal brain representations that predict post-intervention changes in episodic memory across trials. Foundation models outperformed conventional machine learning and deep learning approaches across both trials. Clinically informed adaptation using an external Alzheimers disease cohort further improved performance and robustness to confounders (i.e., head motion, site, and intervention arm), with accuracy up to 82%. Multivariate decomposition of foundation model embeddings identified latent neural patterns associated with episodic memory change with cross-study consistency at baseline that became more spatially distributed at post-intervention. These findings show that rsfMRI foundation models can enable robust and generalizable identification of latent neural patterns linking longitudinal brain dynamics to individual intervention response, laying the foundation for precision-driven neural target discovery in cognitive aging research. Significance StatementInterventions for cognitive aging show highly variable outcomes across individuals, limiting their clinical effectiveness. This study introduces a foundation model-based approach to identify latent neural patterns underlying individual differences in intervention response using resting-state fMRI. By leveraging pretrained models and domain-adaptive fine-tuning, we demonstrate robust and generalizable prediction of cognitive improvement across independent trials. Our findings suggest that latent brain representations, rather than predefined features, provide a scalable pathway toward precision-driven intervention strategies for aging populations.

bioengineering↗

fragilityindex: An R Package for Statistical Fragility Estimates in Biomedicine

Poor reproducibility is a growing crisis in biomedical research. The fragility index was introduced as a convenient measure to estimate how fragile statistical results in clinical trials are to small perturbations in event outcome counts. There is currently no freely available R package to produce this calculation. Furthermore, the original definition of the method is applicable only to 2x2 contingency tables. As such, we developed an R package to calculate fragility index. We have also extended the concept of a statistical fragility index to two of the most commonly used methods in clinical research, survival analysis via weighted log-rank tests and logistic regression, and implemented these technique sin this R package. We describe example applications of these methods to existing publically available datasets. This R package is freely available under the AGPL license on CRAN (https://cran.r-project.org/web/packages/fragilityindex/index.html). The most recent versions may be downloaded and installed via Github (https://github.com/kippjohnson/fragilityindex).

bioinformatics↗

Early therapy with remdesivir and antibody combinations improves COVID-19 disease in mice

Improving the standard of clinical care for individuals infected with SARS-CoV-2 variants is a global health priority. Small molecule antivirals like remdesivir (RDV) and biologics such as human monoclonal antibodies (mAb) have demonstrated therapeutic efficacy against SARS-CoV-2, the causative agent of COVID-19. However, it is not known if combination RDV/mAb will improve outcomes over single agent therapies or whether antibody therapies will remain efficacious against variants. In kinetic studies in a mouse-adapted model of ancestral SARS-CoV-2 pathogenesis, we show that a combination of two mAbs in clinical trials, C144 and C135, have potent antiviral effects against even when initiated 48 hours after infection. The same antibody combination was also effective in prevention and therapy against the B.1.351 variant of concern (VOC). Combining RDV and antibodies provided a modest improvement in outcomes compared to single agents. These data support the continued use of RDV to treat SARS-CoV-2 infections and support the continued clinical development of the C144 and C135 antibody combination to treat patients infected with SARS-CoV-2 variants.

microbiology↗