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42 result(s) for "Gujral, Taranjit S"
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Hippo pathway mediates resistance to cytotoxic drugs
Chemotherapy is widely used for cancer treatment, but its effectiveness is limited by drug resistance. Here, we report a mechanism by which cell density activates the Hippo pathway, which in turn inactivates YAP, leading to changes in the regulation of genes that control the intracellular concentrations of gemcitabine and several other US Food and Drug Administration (FDA)-approved oncology drugs. Hippo inactivation sensitizes a diverse panel of cell lines and human tumors to gemcitabine in 3D spheroid, mouse xenografts, and patient-derived xenograft models. Nuclear YAP enhances gemcitabine effectiveness by down-regulating multidrug transporters as well by converting gemcitabine to a less active form, both leading to its increased intracellular availability. Cancer cell lines carrying genetic aberrations that impair the Hippo signaling pathway showed heightened sensitivity to gemcitabine. These findings suggest that “switching off” of the Hippo–YAP pathway could help to prevent or reverse resistance to some cancer therapies.
Machine learning identifies molecular regulators and therapeutics for targeting SARS‐CoV2‐induced cytokine release
Although 15–20% of COVID‐19 patients experience hyper‐inflammation induced by massive cytokine production, cellular triggers of this process and strategies to target them remain poorly understood. Here, we show that the N‐terminal domain (NTD) of the SARS‐CoV‐2 spike protein substantially induces multiple inflammatory molecules in myeloid cells and human PBMCs. Using a combination of phenotypic screening with machine learning‐based modeling, we identified and experimentally validated several protein kinases, including JAK1, EPHA7, IRAK1, MAPK12, and MAP3K8, as essential downstream mediators of NTD‐induced cytokine production, implicating the role of multiple signaling pathways in cytokine release. Further, we found several FDA‐approved drugs, including ponatinib, and cobimetinib as potent inhibitors of the NTD‐mediated cytokine release. Treatment with ponatinib outperforms other drugs, including dexamethasone and baricitinib, inhibiting all cytokines in response to the NTD from SARS‐CoV‐2 and emerging variants. Finally, ponatinib treatment inhibits lipopolysaccharide‐mediated cytokine release in myeloid cells in vitro and lung inflammation mouse model. Together, we propose that agents targeting multiple kinases required for SARS‐CoV‐2‐mediated cytokine release, such as ponatinib, may represent an attractive therapeutic option for treating moderate to severe COVID‐19. SYNOPSIS Massive cytokine production and hyper‐inflammation have been associated with fatal SARS‐CoV‐2 infection outcomes. Phenotypic screening combined with machine learning‐based modeling identifies regulators and therapeutics for targeting SARS‐CoV‐2‐induced cytokine release. The N‐terminus domain (NTD) of the SARS‐CoV‐2 spike protein induces multiple inflammatory molecules in myeloid cells and PBMCs. Machine learning‐based drug screening approaches identify several kinases including JAK1, EPHA7, IRAK1, MAPK12, and MAP3K8 as essential downstream mediators of NTD‐induced cytokine release. FDA‐approved multi‐kinase inhibitors, including Ponatinib and Cobimetinib, are identified as potent inhibitors of SARS‐CoV‐2 and lipopolysaccharide‐mediated cytokine release. Graphical Abstract Massive cytokine production and hyper‐inflammation have been associated with fatal SARS‐CoV‐2 infection outcomes. Phenotypic screening combined with machine learning‐based modeling identifies regulators and therapeutics for targeting SARS‐CoV‐2‐induced cytokine release.
Polypharmacology-based kinome screen identifies new regulators of KSHV reactivation
Kaposi’s sarcoma-associated herpesvirus (KSHV) causes several human diseases including Kaposi’s sarcoma (KS), a leading cause of cancer in Africa and in patients with AIDS. KS tumor cells harbor KSHV predominantly in a latent form, while typically <5% contain lytic replicating virus. Because both latent and lytic stages likely contribute to cancer initiation and progression, continued dissection of host regulators of this biological switch will provide insights into fundamental pathways controlling the KSHV life cycle and related disease pathogenesis. Several cellular protein kinases have been reported to promote or restrict KSHV reactivation, but our knowledge of these signaling mediators and pathways is incomplete. We employed a polypharmacology-based kinome screen to identify specific kinases that regulate KSHV reactivation. Those identified by the screen and validated by knockdown experiments included several kinases that enhance lytic reactivation: ERBB2 (HER2 or neu ), ERBB3 (HER3), ERBB4 (HER4), MKNK2 (MNK2), ITK, TEC, and DSTYK (RIPK5). Conversely, ERBB1 (EGFR1 or HER1), MKNK1 (MNK1) and FRK (PTK5) were found to promote the maintenance of latency. Mechanistic characterization of ERBB2 pro-lytic functions revealed a signaling connection between ERBB2 and the activation of CREB1, a transcription factor that drives KSHV lytic gene expression. These studies provided a proof-of-principle application of a polypharmacology-based kinome screen for the study of KSHV reactivation and enabled the discovery of both kinase inhibitors and specific kinases that regulate the KSHV latent-to-lytic replication switch.
Vertical silicon nanowires as a universal platform for delivering biomolecules into living cells
A generalized platform for introducing a diverse range of biomolecules into living cells in high-throughput could transform how complex cellular processes are probed and analyzed. Here, we demonstrate spatially localized, efficient, and universal delivery of biomolecules into immortalized and primary mammalian cells using surface-modified vertical silicon nanowires. The method relies on the ability of the silicon nanowires to penetrate a cell's membrane and subsequently release surface-bound molecules directly into the cell's cytosol, thus allowing highly efficient delivery of biomolecules without chemical modification or viral packaging. This modality enables one to assess the phenotypic consequences of introducing a broad range of biological effectors (DNAs, RNAs, peptides, proteins, and small molecules) into almost any cell type. We show that this platform can be used to guide neuronal progenitor growth with small molecules, knock down transcript levels by delivering siRNAs, inhibit apoptosis using peptides, and introduce targeted proteins to specific organelles. We further demonstrate codelivery of siRNAs and proteins on a single substrate in a microarray format, highlighting this technology's potential as a robust, monolithic platform for high-throughput, miniaturized bioassays.
A kinase to cytokine explorer to identify molecular regulators and potential therapeutic opportunities
Cytokines and chemokines are secreted proteins that regulate various biological processes, such as inflammation, immune response, and cell differentiation. Therefore, disruption of signaling pathways involving these proteins has been linked to a range of diseases, including cancer. However, targeting individual cytokines, chemokines, or their receptors is challenging due to their regulatory redundancy and incomplete understanding of their signaling networks. To transform these difficult-to-drug targets into a pharmacologically manageable class, we developed a web-based platform called KinCytE. This platform was designed to link the effects of kinase inhibitors, a well-established class of drugs, with cytokine and chemokine release and signaling networks. The resulting KinCytE platform enables users to investigate protein kinases that regulate specific cytokines or chemokines, generate a ranked list of FDA-approved kinase inhibitors that affect cytokine/chemokine activity, and explore and visualize cytokine signaling network thus facilitating drugging this challenging target class. KinCytE is freely accessible via https://atlas.fredhutch.org/kincyte .
DNAJB1-PRKACA fusion protein-regulated LINC00473 promotes tumor growth and alters mitochondrial fitness in fibrolamellar carcinoma
Fibrolamellar carcinoma (FLC) is a rare liver cancer that disproportionately affects adolescents and young adults. Currently, no standard of care is available and there remains a dire need for new therapeutics. Most patients harbor the fusion oncogene DNAJB1-PRKACA (DP fusion), but clinical inhibitors are not yet developed and it is critical to identify downstream mediators of FLC pathogenesis. Here, we identify long noncoding RNA LINC00473 among the most highly upregulated genes in FLC tumors and determine that it is strongly suppressed by RNAi-mediated inhibition of the DP fusion in FLC tumor epithelial cells. We show by loss- and gain-of-function studies that LINC00473 suppresses apoptosis, increases the expression of FLC marker genes, and promotes FLC growth in cell-based and in vivo disease models. Mechanistically, LINC00473 plays an important role in promoting glycolysis and altering mitochondrial activity. Specifically, LINC00473 knockdown leads to increased spare respiratory capacity, which indicates mitochondrial fitness. Overall, we propose that LINC00473 could be a viable target for this devastating disease.
Olverembatinib inhibits SARS‐CoV‐2‐Omicron variant‐mediated cytokine release in human peripheral blood mononuclear cells
Graphical Abstract The N‐terminus domain (NTD) of the SARS‐CoV‐2 Omicron variant spike protien strongly induces multiple inflammatory molecules in human peripheral blood mononuclear cells, unaffected by the mutations observed in the NTD. Olverembatinib, a clinical‐stage multi‐kinase inhibitor, potently inhibits Omicron NTD‐mediated cytokine release.
Identifying host regulators and inhibitors of liver stage malaria infection using kinase activity profiles
Plasmodium parasites have extensive needs from their host hepatocytes during the obligate liver stage of infection, yet there remains sparse knowledge of specific host regulators. Here we assess 34 host-targeted kinase inhibitors for their capacity to eliminate Plasmodium yoelii -infected hepatocytes. Using pre-existing activity profiles of each inhibitor, we generate a predictive computational model that identifies host kinases, which facilitate Plasmodium yoelii liver stage infection. We predict 47 kinases, including novel and previously described kinases that impact infection. The impact of a subset of kinases is experimentally validated, including Receptor Tyrosine Kinases, members of the MAP Kinase cascade, and WEE1. Our approach also predicts host-targeted kinase inhibitors of infection, including compounds already used in humans. Three of these compounds, VX-680, Roscovitine and Sunitinib, each eliminate >85% of infection. Our approach is well-suited to uncover key host determinants of infection in difficult model systems, including field-isolated parasites and/or emerging pathogens. Host kinases facilitate Plasmodium liver stage (LS) infection, but systematic accounting of important players is lacking. Here, the authors use a computational approach and kinase activity profiles to identify host kinase regulators of LS infection and drugs that could eliminate parasite burden.
Anesthetics inhibit phosphorylation of the ribosomal protein S6 in mouse cultured cortical cells and developing brain
The development and maintenance of neural circuits is highly sensitive to neural activity. General anesthetics have profound effects on neural activity and, as such, there is concern that these agents may alter cellular integrity and interfere with brain wiring, such as when exposure occurs during the vulnerable period of brain development. Under those conditions, exposure to anesthetics in clinical use today causes changes in synaptic strength and number, widespread apoptosis, and long-lasting cognitive impairment in a variety of animal models. Remarkably, most anesthetics produce these effects despite having differing receptor mechanisms of action. We hypothesized that anesthetic agents mediate these effects by inducing a shared signaling pathway. We exposed cultured cortical cells to propofol, etomidate, or dexmedetomidine and assessed the protein levels of dozens of signaling molecules and post-translational modifications using reverse phase protein arrays. To probe the role of neural activity, we performed separate control experiments to alter neural activity with non-anesthetics. Having identified anesthetic-induced changes , we investigated expression of the target proteins in the cortex of sevoflurane anesthetized postnatal day 7 mice by Western blotting. All the anesthetic agents tested reduced phosphorylation of the ribosomal protein S6, an important member of the mTOR signaling pathway. We found a comparable decrease in cortical S6 phosphorylation by Western blotting in sevoflurane anesthetized neonatal mice. Using a systems approach, we determined that propofol, etomidate, dexmedetomidine, and APV/TTX all similarly modulate a signaling module that includes pS6 and other cell mediators of the mTOR-signaling pathway. Reduction in S6 phosphorylation and subsequent suppression of the mTOR pathway may be a common and novel signaling event that mediates the impact of general anesthetics on neural circuit development.