The mechanisms underlying Zika virus (ZIKV)-related microcephaly and other neurodevelopment defects remain poorly understood. Here, we describe the derivation and characterization, including ...single-cell RNA-seq, of neocortical and spinal cord neuroepithelial stem (NES) cells to model early human neurodevelopment and ZIKV-related neuropathogenesis. By analyzing human NES cells, organotypic fetal brain slices, and a ZIKV-infected micrencephalic brain, we show that ZIKV infects both neocortical and spinal NES cells as well as their fetal homolog, radial glial cells (RGCs), causing disrupted mitoses, supernumerary centrosomes, structural disorganization, and cell death. ZIKV infection of NES cells and RGCs causes centrosomal depletion and mitochondrial sequestration of phospho-TBK1 during mitosis. We also found that nucleoside analogs inhibit ZIKV replication in NES cells, protecting them from ZIKV-induced pTBK1 relocalization and cell death. We established a model system of human neural stem cells to reveal cellular and molecular mechanisms underlying neurodevelopmental defects associated with ZIKV infection and its potential treatment.
Display omitted
•Derivation of human neocortical and spinal cord neuroepithelial stem (NES) cells•Zika virus (ZIKV) infects NES cells and radial glia, impairing mitosis and survival•ZIKV induces mitochondrial sequestration of centrosomal phospho-TBK1•Nucleoside analogs inhibit ZIKV replication, protecting NES cells from cell death
Onorati et al. establish neuroepithelial stem (NES) cells as a model for studying human neurodevelopment and ZIKV-induced microcephaly. Together with analyses in human brain slices and microcephalic human fetal tissue, they find that ZIKV predominantly infects NES and radial glial cells, reveal a pivotal role for pTBK1, and find that nucleoside analogs inhibit ZIKV replication, protecting NES cells from cell death.
The integrity of the epidermis and mucosal epithelia is highly dependent on resident self-renewing stem cells, which makes them vulnerable to physical and chemical insults compromising the ...repopulating capacity of the epithelial stem cell compartment. This is frequently the case in cancer patients receiving radiation or chemotherapy, many of whom develop mucositis, a debilitating condition involving painful and deep mucosal ulcerations. Here, we show that inhibiting the mammalian target of rapamycin (mTOR) with rapamycin increases the clonogenic capacity of primary human oral keratinocytes and their resident self-renewing cells by preventing stem cell senescence. This protective effect of rapamycin is mediated by the increase in expression of mitochondrial superoxide dismutase (MnSOD), and the consequent inhibition of ROS formation and oxidative stress. mTOR inhibition also protects from the loss of proliferative basal epithelial stem cells upon ionizing radiation in vivo, thereby preserving the integrity of the oral mucosa and protecting from radiation-induced mucositis.
Display omitted
► Rapamycin increases the repopulating capacity of human epithelial stem cells ► mTOR inhibition prevents epithelial stem cell senescence ► mTOR inhibition protects from oxidative stress by increasing MnSOD expression ► Rapamycin protects from radiation-induced oral ulcers and mucositis
Targeting mTOR with rapamycin, a known drug approved in other contexts, protects human epithelial stem cells from replicative senescence after radiation treatment. These findings highlight a potential treatment approach for mucositis, a common and painful side effect of many forms of cancer therapy.
The importance of mesenchymal stem cells (MSC) in vascular regeneration is becoming increasingly recognized. However, few in vitro studies have been performed to identify the effects of environmental ...elasticity on the differentiation of MSC into vascular cell types. Electrospinning and photopolymerization techniques were used to fabricate a three-dimensional (3-D) polyethylene glycol dimethacrylate nanofiber hydrogel matrix with tunable elasticity for use as a cellular substrate. Compression testing demonstrated that the elastic modulus of the hydrated 3-D matrices ranged from 2 to 15kPa, similar to the in vivo elasticity of the intima basement membrane and media layer. MSC seeded on rigid matrices (8–15kPa) showed an increase in cell area compared with those seeded on soft matrices (2–5kPa). Furthermore, the matrix elasticity guided the cells to express different vascular-specific phenotypes with high differentiation efficiency. Around 95% of MSC seeded on the 3-D matrices with an elasticity of 3kPa showed Flk-1 endothelial markers within 24h, while only 20% of MSC seeded on the matrices with elasticity >8kPa demonstrated Flk-1 marker. In contrast, ∼80% of MSC seeded on 3-D matrices with elasticity >8kPa demonstrated smooth muscle α-actin marker within 24h, while fewer than 10% of MSC seeded on 3-D matrices with elasticity <5kPa showed α-actin markers. The ability to control MSC differentiation into either endothelial or smooth muscle-like cells based purely on the local elasticity of the substrate could be a powerful tool for vascular tissue regeneration.
Lenvatinib in combination with pembrolizumab or everolimus has activity against advanced renal cell carcinoma. The efficacy of these regimens as compared with that of sunitinib is unclear.
In this ...phase 3 trial, we randomly assigned (in a 1:1:1 ratio) patients with advanced renal cell carcinoma and no previous systemic therapy to receive lenvatinib (20 mg orally once daily) plus pembrolizumab (200 mg intravenously once every 3 weeks), lenvatinib (18 mg orally once daily) plus everolimus (5 mg orally once daily), or sunitinib (50 mg orally once daily, alternating 4 weeks receiving treatment and 2 weeks without treatment). The primary end point was progression-free survival, as assessed by an independent review committee in accordance with Response Evaluation Criteria in Solid Tumors, version 1.1. Overall survival and safety were also evaluated.
A total of 1069 patients were randomly assigned to receive lenvatinib plus pembrolizumab (355 patients), lenvatinib plus everolimus (357), or sunitinib (357). Progression-free survival was longer with lenvatinib plus pembrolizumab than with sunitinib (median, 23.9 vs. 9.2 months; hazard ratio for disease progression or death, 0.39; 95% confidence interval CI, 0.32 to 0.49; P<0.001) and was longer with lenvatinib plus everolimus than with sunitinib (median, 14.7 vs. 9.2 months; hazard ratio, 0.65; 95% CI, 0.53 to 0.80; P<0.001). Overall survival was longer with lenvatinib plus pembrolizumab than with sunitinib (hazard ratio for death, 0.66; 95% CI, 0.49 to 0.88; P = 0.005) but was not longer with lenvatinib plus everolimus than with sunitinib (hazard ratio, 1.15; 95% CI, 0.88 to 1.50; P = 0.30). Grade 3 or higher adverse events emerged or worsened during treatment in 82.4% of the patients who received lenvatinib plus pembrolizumab, 83.1% of those who received lenvatinib plus everolimus, and 71.8% of those who received sunitinib. Grade 3 or higher adverse events occurring in at least 10% of the patients in any group included hypertension, diarrhea, and elevated lipase levels.
Lenvatinib plus pembrolizumab was associated with significantly longer progression-free survival and overall survival than sunitinib. (Funded by Eisai and Merck Sharp and Dohme; CLEAR ClinicalTrials.gov number, NCT02811861.).
Abstract
Acute heart failure (HF) and in particular, cardiogenic shock are associated with high morbidity and mortality. A therapeutic dilemma is that the use of positive inotropic agents, such as ...catecholamines or phosphodiesterase-inhibitors, is associated with increased mortality. Newer drugs, such as levosimendan or omecamtiv mecarbil, target sarcomeres to improve systolic function putatively without elevating intracellular Ca2+. Although meta-analyses of smaller trials suggested that levosimendan is associated with a better outcome than dobutamine, larger comparative trials failed to confirm this observation. For omecamtiv mecarbil, Phase II clinical trials suggest a favourable haemodynamic profile in patients with acute and chronic HF, and a Phase III morbidity/mortality trial in patients with chronic HF has recently begun. Here, we review the pathophysiological basis of systolic dysfunction in patients with HF and the mechanisms through which different inotropic agents improve cardiac function. Since adenosine triphosphate and reactive oxygen species production in mitochondria are intimately linked to the processes of excitation–contraction coupling, we also discuss the impact of inotropic agents on mitochondrial bioenergetics and redox regulation. Therefore, this position paper should help identify novel targets for treatments that could not only safely improve systolic and diastolic function acutely, but potentially also myocardial structure and function over a longer-term.
Abstract Curcumin (Cur) has been demonstrated to have wide pharmacological window including anti-oxidant and anti-inflammatory properties. However, phototoxicity under sunlight exposure and poor ...biological availability limits its applicability. We have synthesized biodegradable and non-toxic polymer-poly (lactic-co-glycolic) acid (PLGA) encapsulated formulation of curcumin (PLGA-Cur-NPs) of 150 nm size range. Photochemically free curcumin generates ROS, lipid peroxidation and induces significant UVA and UVB mediated impaired mitochondrial functions leading to apoptosis/necrosis and cell injury in two different origin cell lines viz., mouse fibroblasts-NIH-3T3 and human keratinocytes-HaCaT as compared to PLGA-Cur-NPs. Molecular docking studies suggested that intact curcumin from nanoparticles, bind with BAX in BIM SAHB site and attenuate it to undergo apoptosis while upregulating anti-apoptotic genes like BCL2. Real time studies and western blot analysis with specific phosphorylation inhibitor of ERK1 and AKT1/2/3 confirm the involvement of ERK/AKT signaling molecules to trigger the survival cascade in case of PLGA-Cur-NPs. Our finding demonstrates that low level sustained release of curcumin from PLGA-Cur-NPs could be a promising way to protect the adverse biological interactions of photo-degradation products of curcumin upon the exposure of UVA and UVB. Hence, the applicability of PLGA-Cur-NPs could be suggested as prolonged radical scavenging ingredient in curcumin containing products.
The Caenorhabditis elegans SUN domain protein, UNC-84, functions in nuclear migration and anchorage in the soma. We discovered a novel role for UNC-84 in DNA damage repair and meiotic recombination. ...Loss of UNC-84 leads to defects in the loading and disassembly of the recombinase RAD-51. Similar to mutations in Fanconi anemia (FA) genes, unc-84 mutants and human cells depleted of Sun-1 are sensitive to DNA cross-linking agents, and sensitivity is rescued by the inactivation of nonhomologous end joining (NHEJ). UNC-84 also recruits FA nuclease FAN-1 to the nucleoplasm, suggesting that UNC-84 both alters the extent of repair by NHEJ and promotes the processing of cross-links by FAN-1. UNC-84 interacts with the KASH protein ZYG-12 for DNA damage repair. Furthermore, the microtubule network and interaction with the nucleoskeleton are important for repair, suggesting that a functional linker of nucleoskeleton and cytoskeleton (LINC) complex is required. We propose that LINC complexes serve a conserved role in DNA repair through both the inhibition of NHEJ and the promotion of homologous recombination at sites of chromosomal breaks.
Ionizing radiation (IR) is effectively used in cancer therapy. However, in subsets of patients, a few radioresistant cancer cells survive and cause disease relapse with metastatic progression. The ...MET oncogene encodes the hepatocyte growth factor (HGF) receptor and is known to drive "invasive growth", a regenerative and prosurvival program unduly activated in metastasis.
Human tumor cell lines (MDA-MB-231, MDA-MB-435S, U251) were subjected to therapeutic doses of IR. MET mRNA, and protein expression and signal transduction were compared in treated and untreated cells, and the involvement of the DNA-damage sensor ataxia telangiectasia mutated (ATM) and the transcription factor nuclear factor kappa B (NF-κB) in activating MET transcription were analyzed by immunoblotting, chromatin immunoprecipitation, and use of NF-κB silencing RNA (siRNA). Cell invasiveness was measured in wound healing and transwell assays, and cell survival was measured in viability and clonogenic assays. MET was inhibited by siRNA or small-molecule kinase inhibitors (PHA665752 or JNJ-38877605). Combinations of MET-targeted therapy and radiotherapy were assessed in MDA-MB-231 and U251 xenografts (n = 5-6 mice per group). All P values were from two-sided tests.
After irradiation, MET expression in cell lines was increased up to fivefold via activation of ATM and NF-κB. MET overexpression increased ligand-independent MET phosphorylation and signal transduction, and rendered cells more sensitive to HGF. Irradiated cells became more invasive via a MET-dependent mechanism that was further enhanced in the presence of HGF. MET silencing by siRNA or inhibition of its kinase activity by treatment with PHA665752 or JNJ-38877605 counteracted radiation-induced invasiveness, promoted apoptosis, and prevented cells from resuming proliferation after irradiation in vitro. Treatment with MET inhibitors enhanced the efficacy of IR to stop the growth of or to induce the regression of xenografts (eg, at day 13, U251 xenografts, mean volume increase relative to mean tumor volume at day 0: vehicle = 438%, 5 Gy IR = 151%, 5 Gy IR + JNJ-38877605 = 76%; difference, IR vs JNJ-38877604 + IR = 75%, 95% CI = 59% to 91%, P = .01).
IR induces overexpression and activity of the MET oncogene through the ATM-NF-κB signaling pathway; MET, in turn, promotes cell invasion and protects cells from apoptosis, thus supporting radioresistance. Drugs targeting MET increase tumor cell radiosensitivity and prevent radiation-induced invasiveness.
Mast cells are tissue-resident immune cells that play a key role in inflammation and allergy. Here we show that interaction of mast cells with antibody-targeted cells induces the polarized exocytosis ...of their granules resulting in a sustained exposure of effector enzymes, such as tryptase and chymase, at the cell-cell contact site. This previously unidentified mast cell effector mechanism, which we name the antibody-dependent degranulatory synapse (ADDS), is triggered by both IgE- and IgG-targeted cells. ADDSs take place within an area of cortical actin cytoskeleton clearance in the absence of microtubule organizing centre and Golgi apparatus repositioning towards the stimulating cell. Remarkably, IgG-mediated degranulatory synapses also occur upon contact with opsonized Toxoplasma gondii tachyzoites resulting in tryptase-dependent parasite death. Our results broaden current views of mast cell degranulation by revealing that human mast cells form degranulatory synapses with antibody-targeted cells and pathogens for dedicated secretion and defence.
PDF
