Biology subjects

Islam, S.

Publications and source records attributed to Islam, S..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

Identification of transcriptome-wide cobalt chloride-induced hypoxia-responsive long noncoding RNAs regulated by cytoplasmic mRNA capping enzyme

Long non-coding RNAs (lncRNAs) are key regulators of gene expression in human cancers, influencing tumor microenvironment (TME). Hypoxia, a hallmark of solid tumors, elevates hypoxia-inducible factor 1 (HIF-1), which regulates hypoxia-responsive lncRNAs (HRLs). These HRLs are essential in regulating gene expression under hypoxic conditions at both transcriptional and post-transcriptional levels. However, the mechanisms governing the post-transcriptional regulation of lncRNAs are not fully understood. It has been shown that the cytoplasmic pool of mRNA capping enzyme (cCE) can post-transcriptionally regulate its substrate uncapped mRNAs and lncRNAs in the cytoplasm, thereby preventing their degradation. Our previous study showed elevated expression of cCE under hypoxic conditions. This study aimed to determine whether cCE influences the transcriptome-wide HRLs in CoCl2-induced hypoxia in osteosarcoma U2OS cells. We identified 306 known lncRNAs with significant differential expression under hypoxic conditions, including 137 upregulated and 169 downregulated by RNA sequencing. Gene Ontology enrichment analysis revealed their distinct association with various cancers. Our investigation aimed to ascertain whether the cCE post-transcriptionally regulates these HRLs. Overexpression of a dominant negative form of cCE suggested cCE might post-transcriptionally regulate these HRLs. Future research should focus on understanding how cCE influences substrate HRLs, which play a crucial role in the bidirectional signaling circuit between TME and cancer cells under hypoxic stress as well as establishing cCE as a key factor that may alter cellular responses to hypoxia by stabilizing cCE-targeted lncRNAs.

molecular biology↗

bioRxiv2024

Volumetric and Diffusion Tensor Imaging biomarkers indicating long lasting post-concussion abnormalities in a youth pig model of mild Traumatic Brain Injury

Mild Traumatic Brain Injury (mTBI) caused by sports-related incidents in children and youth can lead to prolonged cognitive impairments, underscoring the importance of improved diagnosis and comprehension of its enduring impacts on neuropathology. A pig model was chosen for its similarities to the human brain in terms of gyrencephalic structure, size, and regional proportions, and a closed-head mTBI was induced in adolescent pigs. In this study, 12 (n=4 male and n=8 female) 16-weeks old Yucatan pigs were tested; n=6 received mTBI and n=6 received a Sham procedure. This study utilized T1-weighted imaging to assess volumetric alterations in different regions of the brain and diffusion tensor imaging (DTI) to examine microstructural damage in white matter. The pigs were imaged at one and three months post-injury. Our volumetric analysis of key white and gray matter regions showed significant longitudinal changes in pigs with mTBI compared to sham controls. The observed volume increases may be attributed to swelling, neuroinflammation, or hyperactivity. Fractional anisotropy (FA) values derived from DTI images demonstrated an increase in corpus callosum from 1 month to 3 months only in mTBI pigs. Additionally, comparisons of the left and right internal capsules revealed a decrease in FA in the right internal capsule for mTBI pigs, likely due to the impact being slightly localized to the right side of the brain, which may indicate demyelination. Thus, the injury has disrupted the maturation of white and gray matter of the developing brain. This signifies the need for longitudinal investigations after mTBI to comprehensively assess its long-term effects and contribute to the clinical management of concussion in youth.

bioengineering↗

bioRxiv2024

Switch-like Gene Expression Modulates Disease Susceptibility

A fundamental challenge in biomedicine is understanding the mechanisms predisposing individuals to disease. While previous research has suggested that switch-like gene expression is crucial in driving biological variation and disease susceptibility, a systematic analysis across multiple tissues is still lacking. By analyzing transcriptomes from 943 individuals across 27 tissues, we identified 1,013 switch-like genes. We found that only 31 (3.1%) of these genes exhibit switch-like behavior across all tissues. These universally switch-like genes appear to be genetically driven, with large exonic genomic structural variants explaining five ([~]18%) of them. The remaining switch-like genes exhibit tissue-specific expression patterns. Notably, tissue-specific switch-like genes tend to be switched on or off in unison within individuals, likely under the influence of tissue-specific master regulators, including hormonal signals. Among our most significant findings, we identified hundreds of concordantly switched-off genes in the stomach and vagina that are linked to gastric cancer (41-fold, p<10-4) and vaginal atrophy (44-fold, p<10-4), respectively. Experimental analysis of vaginal tissues revealed that low systemic levels of estrogen lead to a significant reduction in both the epithelial thickness and the expression of the switch-like gene ALOX12. We propose a model wherein the switching off of driver genes in basal and parabasal epithelium suppresses cell proliferation therein, leading to epithelial thinning and, therefore, vaginal atrophy. Our findings underscore the significant biomedical implications of switch-like gene expression and lay the groundwork for potential diagnostic and therapeutic applications.

bioinformatics↗

bioRxiv2024

Single-molecule tracking reveals the dynamics of Ipl1 recruitment to the kinetochores and spindles in S. cerevisiae

Aurora kinase B, Ipl1 in Saccharomyces cerevisiae, is the master regulator of cell division required for checkpoint regulation, spindle assembly and disassembly, chromosome segregation, and cytokinesis. Decades of research employed ensemble averaging methods to understand its dynamics and function; however, the dynamic information was lost due to population-based averaging. Here, we use single-molecule imaging and tracking (SMIT) to quantify the recruitment dynamics of Ipl1 at the kinetochores and spindles in live cells. Our data suggest that Ipl1 is recruited to these locations with different dynamics. We have demonstrated how the recruitment dynamics of Ipl1 at the kinetochores during metaphase changes in the presence and absence of tension across the kinetochore, in the absence of protein phosphatase 1 (Glc7), and the absence of its known recruiters (Ctf19 and Bub1). The SMIT of other chromosome passenger complex members suggests its hierarchical assembly at the kinetochore. Hence, SMIT provides a dynamic view of the Ipl1 trafficking at the kinetochores and spindles.

cell biology↗

bioRxiv2024

A shared threat-anticipation circuit is dynamically engaged at different moments by certain and uncertain threat

Temporal dynamics play a central role in models of emotion: "fear" is widely conceptualized as a phasic response to certain-and-imminent danger, whereas "anxiety" is a sustained response to uncertain-or-distal harm. Yet the underlying neurobiology remains contentious. Leveraging a translationally relevant fMRI paradigm and theory-driven modeling approach in 220 adult humans, we demonstrate that certain- and uncertain-threat anticipation recruit a shared circuit that encompasses the central extended amygdala (EAc), periaqueductal gray, midcingulate, and anterior insula. This circuit exhibits persistently elevated activation when threat is uncertain and distal, and transient bursts of activation just before certain encounters with threat. Although there is agreement that the EAc plays a critical role in orchestrating responses to threat, confusion persists about the respective contributions of its major subdivisions, the bed nucleus of the stria terminalis (BST) and central nucleus of the amygdala (Ce). Here we used anatomical regions-of-interest to demonstrate that the BST and Ce exhibit statistically indistinguishable threat dynamics. Both regions exhibited activation dynamics that run counter to popular models, with the Ce showing sustained responses to uncertain-and-distal threat and the BST showing phasic responses to certain-and-imminent threat. For many scientists, feelings are the hallmark of fear and anxiety. Here we used an independently validated multivoxel brain signature to covertly probe the moment-by-moment dynamics of anticipatory distress for the first time. Results mirrored the dynamics of neural activation. These observations provide fresh insights into the neurobiology of threat-elicited emotions and set the stage for more ambitious clinical and mechanistic research. SIGNIFICANCE STATEMENT"Fear" is widely viewed as a phasic response to certain-and-imminent danger, whereas "anxiety" is a sustained response to uncertain-or-distal harm. Prior work has begun to reveal the neural systems recruited by certain and uncertain anticipated threats, but has yet to rigorously plumb the moment-by-moment dynamics anticipated by theory. Here we used a novel combination of neuroimaging techniques to demonstrate that certain and uncertain threat recruit a common threat-anticipation circuit. Activity in this circuit and covert measures of distress showed similar patterns of context-dependent dynamics, exhibiting persistent increases when anticipating uncertain-threat encounters and transient surges just before certain encounters. These observations provide fresh insights into the neurobiology of fear and anxiety, laying the groundwork for more ambitious clinical and mechanistic research.

neuroscience↗

bioRxiv2024

Cytoplasmic mRNA capping enzyme is regulated by hypoxia inducible factor HIF1α and controls stability of the target lncRNAs during hypoxia

In response to hypoxia, hypoxia-inducible factors (HIFs) control the transcriptomic output to mitigate the hypoxic stress. Long noncoding RNAs (lncRNA) are found to be very crucial in regulating hypoxia. Like mRNAs, lncRNAs are protected by 5 caps that are added by mRNA capping enzyme (CE) in the nucleus. The previous concept that capping takes place in the nucleus was changed by the recognition of a cytoplasmic pool of capping enzyme (cCE). cCE has been shown to recap its substrate uncapped mRNAs or long noncoding RNAs (lncRNAs) present in the cytoplasm, preventing their degradation, even during arsenite-induced oxidative stress. In this study, we examined the effect of CoCl2 induced hypoxia on cCE and its function in regulating the substrate lncRNAs. Here, we show that CoCl2 induced hypoxia elevates the expressions of nuclear and cytoplasmic CE in HIF1 dependent manner as evidenced by Chromatin immunoprecipitation and HIF1 inhibitor experiments. Furthermore, we found cCE post-transcriptionally controls the stability of its target lncRNAs amidst CoCl2 induced hypoxia. These results suggest that cCE, upregulated by HIF1, may act as a posttranscriptional modulator for a few cCE-targeted lncRNAs.

molecular biology↗

bioRxiv2024

Loss of FBXO31-mediated γH2AX foci formation impairs initiation of NHEJ and HR repair pathways, and sensitizes breast cancer to therapy

In response to genotoxic stress, cell initiates complex signalling cascades to combat genomic insults through simultaneous initiation of growth arrest and DNA damage repair process. {gamma}H2AX functions as a crucial initiator in DNA double strand damage repair process. Therefore, {gamma}H2AX foci formation onto the damage sites is essential to initiate the recruitment of repair proteins involved in NHEJ (Non-homologous DNA-end joining) or HR (Homologous recombination) repair process. However, molecular events associated with {gamma}H2AX foci formation onto the DNA damage sites are poorly understood. Here, we show that FBXO31, the first ubiquitin ligase, mediated Lys-63-linked ubiquitination of {gamma}H2AX is essential for its foci formation onto the DNA damage sites to initiate recruitment of proteins involved in NHEJ and HR-mediated DNA damage repair. Therefore, tumors with FBXO31 deficiency show enhanced growth suppression following chemotherapeutic drug treatment because of synthetic lethality, indicating that FBXO31 could be used as a marker for predicting the outcome of chemotherapy treatment.

cancer biology↗

bioRxiv2024

Midbrain Dopaminergic Neuron Development is Regulated by Two Molecularly Distinct Subtypes of Radial Glia Cells

Understanding midbrain dopaminergic (mDA) neuron development is key to advancing cell replacement therapies for Parkinsons disease (PD). Recent single-cell RNA-sequencing (scRNA-seq) studies have identified different subtypes of transient radial glia (Rgl) cell types in the developing mouse and human ventral midbrain. However, their individual functions and their impact on mDA neuron development are unclear. Here we analyze the transcriptome of endogenous mouse and human ventral midbrain Rgl and assess the function of key midbrain floor plate Rgl factors in human stem cells during mDA neuron differentiation. We find that Rgl1 is defined by a neurogenic network centered on Arntl, and that this transcription factor regulates human mDA neurogenesis. Conversely, the transcriptome of Rgl3 is dominated by signaling and extracellular matrix molecules that control different aspects of human mDA neuron development. Thus, our results suggest a function of Rgl1 as a mDA progenitor, and of Rgl3 as a signaling mDA niche cell. Moreover, using human stem cells we demonstrate that new knowledge of cell-type specific intrinsic and extrinsic developmental factors can readily be applied to improve the generation of cells with therapeutic interest, such as human mDA neurons for PD.

neuroscience↗

bioRxiv2024

Visualizing Mitochondrial Heme Flow through GAPDH to Targets in Living Cells and its Regulation by NO

Iron protoporphyrin IX (heme) is an essential cofactor that is chaperoned in mammalian cells by GAPDH in a process regulated by NO. To gain further understanding we generated a tetra-Cys human GAPDH reporter construct (TC-hGAPDH) which after being expressed and labeled with fluorescent FlAsH reagent could indicate heme binding by fluorescence quenching. When purified or expressed in HEK293T mammalian cells, FlAsH-labeled TC-hGAPDH displayed physical, catalytic, and heme binding properties like native GAPDH and its heme binding (2 mol per tetramer) quenched its fluorescence by 45-65%. In live HEK293T cells we could visualize TC-hGAPDH binding mitochondrially-generated heme and releasing it to the hemeprotein target IDO1 by monitoring cell fluorescence in real time. In cells with active mitochondrial heme synthesis, a low-level NO exposure increased heme allocation into IDO1 while keeping steady the level of heme-bound TC-hGAPDH. When mitochondrial heme synthesis was blocked at the time of NO exposure, low NO caused cells to reallocate existing heme from TC-hGAPDH to IDO1 by a mechanism requiring IDO1 be present and able to bind heme. Higher NO exposure had an opposite effect and caused cells to reallocate existing heme from IDO1 to TC-hGAPDH. Thus, with TC-hGAPDH we could follow mitochondrial heme as it travelled onto and through GAPDH to a downstream target (IDO1) in living cells, and to learn that NO acted at or downstream from the GAPDH heme complex to promote a heme reallocation in either direction depending on the level of NO exposure.

cell biology↗

bioRxiv2023

Adolescent social anxiety is associated with diminished discrimination of anticipated threat and safety

Social anxiety--which typically emerges in adolescence--lies on a continuum and, when extreme, can be devastating. Socially anxious individuals are prone to heightened fear, anxiety, and the avoidance of contexts associated with potential social scrutiny. Yet most neuroimaging research has focused on acute social threat. Much less attention has been devoted to understanding the neural systems recruited during the uncertain anticipation of potential encounters with social threat. Here we used a novel fMRI paradigm to probe the neural circuitry engaged during the anticipation and acute presentation of threatening faces and voices in a racially diverse sample of 66 adolescents selectively recruited to encompass a range of social anxiety and enriched for clinically significant levels of distress and impairment. Results demonstrated that adolescents with more severe social anxiety symptoms experience heightened distress when anticipating encounters with social threat, and reduced discrimination of uncertain social threat and safety in the bed nucleus of the stria terminalis (BST), a key division of the central extended amygdala (EAc). Although the EAc--including the BST and central nucleus of the amygdala--was robustly engaged by the acute presentation of threatening faces and voices, the degree of EAc engagement was unrelated to the severity of social anxiety. Together, these observations provide a neurobiologically grounded framework for conceptualizing adolescent social anxiety and set the stage for the kinds of prospective-longitudinal and mechanistic research that will be necessary to determine causation and, ultimately, to develop improved interventions for this often-debilitating illness.

neuroscience↗

bioRxiv2023

Multi-modal skin atlas associates a multicellular immune-stromal community with altered cornification and T cell expansion in atopic dermatitis

In healthy skin, a cutaneous immune system maintains the balance between tolerance towards innocuous environmental antigens and immune responses against pathological agents. In atopic dermatitis (AD), barrier and immune dysfunction result in chronic tissue inflammation. Our understanding of the skin tissue ecosystem in AD remains incomplete with regard to the hallmarks of pathological barrier formation, and cellular state and clonal composition of disease-promoting cells. Here, we generated a multi-modal cell census of 310,691 cells spanning 86 cell subsets from whole skin tissue of 19 adult individuals, including non-lesional and lesional skin from 11 AD patients, and integrated it with 396,321 cells from four studies into a comprehensive human skin cell atlas in health and disease. Reconstruction of human keratinocyte differentiation from basal to cornified layers revealed a disrupted cornification trajectory in AD. This disrupted epithelial differentiation was associated with signals from a unique immune and stromal multicellular community comprised of MMP12+ dendritic cells (DCs), mature migratory DCs, cycling ILCs, NK cells, inflammatory CCL19+ IL4I1+ fibroblasts, and clonally expanded IL13+IL22+IL26+ T cells with overlapping type 2 and type 17 characteristics. Cell subsets within this immune and stromal multicellular community were connected by multiple inter-cellular positive feedback loops predicted to impact community assembly and maintenance. AD GWAS gene expression was enriched both in disrupted cornified keratinocytes and in cell subsets from the lesional immune and stromal multicellular community including IL13+IL22+IL26+ T cells and ILCs, suggesting that epithelial or immune dysfunction in the context of the observed cellular communication network can initiate and then converge towards AD. Our work highlights specific, disease-associated cell subsets and interactions as potential targets in progression and resolution of chronic inflammation.

molecular biology↗

bioRxiv2023

Engineered BCL6 BTB Domain of the Bcl-2 Protein Family shows Dynamic Structural Behavior: Insights from Molecular Dynamics Simulations

Apoptosis is crucially regulated by the Bcl-6 protein, and mutations in this protein can have a significant impact on many malignancies. In this study, we used molecular dynamics simulations to examine the effects of specific mutations (Q8C, R67C, and N84C) in the crystal structure of the BCL6 BTB domain in a compound with pyrazole-pyrimidine ligand. We concentrated on comprehending the dynamics of these alterations and their possible effects on the emergence of cancer. To explore the structural and dynamic changes induced by these mutations, we performed in silico simulations using the GROMACS software suite (version 5.2, 2020.1) on Google Colabs Tesla T4 GPU. The crystal structure of the BCL6 BTB domain in complex with the pyrazole-pyrimidine ligand (PDB ID: 5N20) served as the wild-type reference structure. Mutations were imposed using the Rotamer functions of Chimera. The simulations were carried out for a total duration of 20 ns using a time step of 2 femtoseconds (0.002 ps). The Trajectory profiles of the BCL6 BTB domain protein and its three mutations, Q8C, R67C and N84C, were shown to differ from each other. Based on the analysis of RMSD, RMSF, and Rg, it was determined that the mutant 2 (R67C) protein exhibited increased instability and greater flexibility. In contrast, mutant 3 (N84C) demonstrates a heightened level of compactness and greater stability compared to the remaining protein mutant. PCA also provides information regarding the structural dynamics of these mutants. In addition, the SASA and SASA autocorrelation provides a distinct view of the solvent accessibility of these proteins.

bioinformatics↗

bioRxiv2023

Identification of Therapeutic Leads from Ficus hispida Fruit Phytochemicals against Prostate Cancer Using Pharmacoinformatic and Molecular Dynamics Simulation Approach

Prostate cancer is one of the leading causes of death and the most common cancer type in men. In this study, potential leads from the phytochemicals of Ficus hispida fruit were screened using in silico tools against androgen receptor (AR), a known target for prostate cancer. PASS online and ADMET tools were used to screen specific phytochemicals that are relevant to prostate cancer treatment and have drug-like properties. Of 13, a total of 10 phytochemicals passed PASS online and ADMET screening. Next, a total of three phytochemicals, including nodakenetin (CID: 26305), isowigtheone hydrate (CID: 66728267), and 7-hydroxycoumarin (CID: 5281426) were selected based on their docking scores (-9.946 to -7.653 kcal/mol) and relevance to selective bioactivity. The MD simulation further confirmed the binding stability of these three phytochemicals with their target AR protein and determined that the main amino acid residues mainly responsible for this stability including RMSD, RMSF, and post simulation binding free energies. These findings suggest that these three phytochemicals of Ficus hispida fruit can further be developed as prospective therapeutics against prostate cancer.

bioinformatics↗

bioRxiv2023

Increased bleeding and thrombosis in myeloproliferative neoplasms mediated through altered expression of inherited platelet disorder genes

An altered thrombo-hemorrhagic profile has long been observed in patients with myeloproliferative neoplasms (MPNs). We hypothesized that this observed clinical phenotype may result from altered expression of genes known to harbor genetic variants in bleeding, thrombotic, or platelet disorders. Here, we identify 32 genes from a clinically validated gene panel that were also significantly differentially expressed in platelets from MPN patients as opposed to healthy donors. This work begins to unravel previously unclear mechanisms underlying an important clinical reality in MPNs. Knowledge of altered platelet gene expression in MPN thrombosis/bleeding diathesis opens opportunities to advance clinical care by: (1) enabling risk stratification, in particular, for patients undergoing invasive procedures, and (2) facilitating tailoring of treatment strategies for those at highest risk, for example, in the form of antifibrinolytics, desmopressin or platelet transfusions (not current routine practice). Marker genes identified in this work may also enable prioritization of candidates in future MPN mechanistic as well as outcome studies.

genomics↗

bioRxiv2023

Neuroticism/negative emotionality is associated with increased reactivity to uncertain threat in the bed nucleus of the stria terminalis, not the amygdala

Neuroticism/Negative Emotionality (N/NE)--the tendency to experience anxiety, fear, and other negative emotions--is a fundamental dimension of temperament with profound consequences for health, wealth, and wellbeing. Elevated N/NE is associated with a panoply of adverse outcomes, from reduced socioeconomic attainment to psychiatric illness. Animal research suggests that N/NE reflects heightened reactivity to uncertain threat in the bed nucleus of the stria terminalis (BST) and central nucleus of the amygdala (Ce), but the relevance of these discoveries to humans has remained unclear. Here we used a novel combination of psychometric, psychophysiological, and neuroimaging approaches to rigorously test this hypothesis in an ethnoracially diverse, sex-balanced sample of 220 emerging adults selectively recruited to encompass a broad spectrum of N/NE. Cross-validated robust-regression analyses demonstrated that N/NE is preferentially associated with heightened BST activation during the uncertain anticipation of a genuinely distressing threat (aversive multimodal stimulation), whereas N/NE was unrelated to BST activation during certain-threat anticipation, Ce activation during either type of threat anticipation, or BST/Ce reactivity to threat-related faces. It is often assumed that different threat paradigms are interchangeable assays of individual differences in brain function, yet this has rarely been tested. Our results revealed negligible associations between BST/Ce reactivity to the anticipation of threat and the presentation of threat-related faces, indicating that the two tasks are non-fungible. These observations provide a framework for conceptualizing emotional traits and disorders; for guiding the design and interpretation of biobank and other neuroimaging studies of psychiatric risk, disease, and treatment; and for informing mechanistic research. SIGNIFICANCE STATEMENTNeuroticism/Negative Emotionality (N/NE) is a core dimension of mammalian temperament. Elevated levels of N/NE confer risk for a panoply of adversities--from reduced wealth and divorce to depression and death--yet the underlying neurobiology remains unclear. Here we show that N/NE is associated with heightened activation in the bed nucleus of the stria terminalis (BST) during the uncertain anticipation of a genuinely distressing threat. In contrast, N/NE was unrelated to BST reactivity during the certain anticipation of threat or the acute presentation of threat-related faces, two popular probes of the emotional brain. These findings refine our understanding of what has been termed the single most important psychological risk factor in public health, with implications for on-going biobank and therapeutics research.

neuroscience↗

bioRxiv2023

A new web resource to predict the impact of missense variants at protein interfaces using 3D structural data: Missense3D-PPI

In 2019, we released Missense3D which identifies stereochemical features that are disrupted by a missense variant, such as introducing a buried charge. Missense3D analyses the effect of a missense variant on a single structure and thus may fail to identify as damaging surface variants disrupting a protein interface i.e., a protein-protein interaction (PPI) site. Here we present Missense3D-PPI designed to predict missense variants at PPI interfaces. Our development dataset comprised of 1,279 missense variants (pathogenic n=733, benign n=546) in 434 proteins and 545 experimental structures of PPI complexes. Benchmarking of Missense3D-PPI was performed after dividing the dataset in training (320 benign and 320 pathogenic variants) and testing (226 benign and 413 pathogenic). Structural features affecting PPI, such as disruption of interchain bonds and introduction of unbalanced charged interface residues, were analysed to assess the impact of the variant at PPI. Missense3D-PPIs performance was superior to that of Missense3D: sensitivity 42% versus 8% and accuracy 58% versus 40%, p=4.23x10-16 However, the specificity of Missense3D-PPI was slightly lower compared to Missense3D (84% versus 98%). On our dataset, Missense3D-PPIs accuracy was superior to BeAtMuSiC (p=2.3x10-5), mCSM-PPI2 (p=3.2x10-12) and MutaBind2 (p=0.003). Missense3D-PPI represents a valuable tool for predicting the structural effect of missense variants on biological protein networks and is available at the Missense3D web portal (http://missense3d.bc.ic.ac.uk/missense3d/indexppi.html).

bioinformatics↗

bioRxiv2022

Epicardial reservoir-enabled multidose delivery of exogenous FSTL1 leads to improved cardiac function, healing, and angiogenesis.

Epicardial delivery of human follistatin-like 1 protein (FSTL1) induces significant cardiac benefit following a myocardial infarction (MI). However, the optimal dosing regimen for maximal therapeutic benefit has not yet been elucidated. To investigate the impact of multiple FSTL1 doses, without the confounding effects of multiple surgical procedures for multidose delivery, alternative delivery strategies are needed. Here, we use an epicardial reservoir that allows non-invasive delivery of additional doses after implantation to investigate the impact of single, double, and triple FSTL1 dose regimens in a rat model of MI. Multidose delivery of FSTL1 improves ejection fraction (3 doses), fractional shortening (1, 2 and 3 doses), and chamber stiffness (2 doses) 28 days after MI. Histologically, multiple FSTL1 doses increase ventricular wall thickness (2 and 3 doses) and reduce infarct size (1, 2, and 3 doses). We also demonstrate a dose-dependent increase in blood vessel number and density in the infarct zone, with three FSTL1 doses leading to the highest improvements. This study shows that multidose delivery of FSTL1 improves cardiac function, healing, and angiogenesis following MI. The epicardial delivery platform used here may be essential in optimizing dosing regimens of various bioagent combinations for a range of clinical indications.

bioengineering↗

bioRxiv2022

Identification of Long noncoding RNAs as substrate of cytoplasmic Capping Enzyme

Cytoplasmic capping returns a cap to specific mRNAs thus protecting uncapped RNAs from decay. Prior to the identification of cytoplasmic capping, uncapped mRNAs were thought to be degraded. Here, we test whether long non-coding RNAs (lncRNAs) are cytoplasmic capping enzyme (cCE) substrates. The subcellular localization of fourteen lncRNAs associated with sarcomas were examined in U2OS osteosarcoma cells. We used 5 rapid amplification of cDNA ends (RACE) to assay uncapped forms of these lncRNAs. Inhibiting cytoplasmic capping elevated uncapped forms of selected lncRNAs indicating a plausible role of cCE in targeting them. Analysis of published cap analysis of gene expression (CAGE) data shows increased prevalence of certain 5-RACE cloned sequences suggesting that these uncapped lncRNAs are cytoplasmic capping targets.

molecular biology↗