Human Cells Research Articles

Genetically engineered human embryonic kidney cells as a novel vehicle for dual patch clamp study of human gap junction channels.

Mutations in more than half of human connexin genes encoding gap junction subunits have been linked to inherited human diseases. Functional studies of human gap junction (GJ) channels are essential for revealing mechanistic insights on the etiology of disease-linked connexin mutants. However, the commonly used Xenopus oocytes, N2A, HeLa, and other model cells for recombinant expression of human connexins have different and significant limitations. Here we developed a human cell line (HEK293) with each of the endogenous connexins (Cx43 and Cx45) knocked out using the CRISPR-Cas9 system. Double knockout HEK293 cells showed no background GJ coupling, were easily transfected with several human connexin genes (such as those encoding Cx46, Cx50, Cx37, Cx45, Cx26, and Cx36) which successfully formed functional GJs and were readily accessible for dual patch clamp analysis. Single knockout Cx43 or Cx45 HEK cell lines could also be used to characterize human GJ channels formed by Cx45 or Cx43, respectively, with an expression level suitable for studying macroscopic and single channel GJ channel properties. A cardiac arrhythmia linked Cx45 mutant R184G failed to form functional GJs in DKO HEK293 cells with impaired localizations. These genetically engineered HEK293 cells are well suited for patch clamp study of human GJ channels.

Bcl-2 dependent modulation of Hippo pathway in cancer cells

IntroductionBcl-2 and Bcl-xL are the most studied anti-apoptotic members of Bcl-2 family proteins. We previously characterized both of them, not only for their role in regulating apoptosis and resistance to therapy in cancer cells, but also for their non-canonical functions, mainly including promotion of cancer progression, metastatization, angiogenesis, and involvement in the crosstalk among cancer cells and components of the tumor microenvironment. Our goal was to identify transcriptional signature and novel cellular pathways specifically modulated by Bcl-2.MethodsWe performed RNAseq analysis of siRNA-mediated transient knockdown of Bcl-2 or Bcl-xL in human melanoma cells and gene ontology analysis to identify a specific Bcl-2 transcriptional signature. Expression of genes modulated by Bcl-2 and associated to Hippo pathway were validated in human melanoma, breast adenocarcinoma and non-small cell lung cancer cell lines by qRT-PCR. Western blotting analysis were performed to analyse protein expression of upstream regulators of YAP and in relation to different level of Bcl-2 protein. The effects of YAP silencing in Bcl-2 overexpressing cancer cells were evaluated in migration and cell viability assays in relation to different stiffness conditions. In vitro wound healing assays and co-cultures were used to evaluate cancer-specific Bcl-2 ability to activate fibroblasts.ResultsWe demonstrated the Bcl-2-dependent modulation of Hippo Pathway in cancer cell lines from different tumor types by acting on upstream YAP regulators. YAP inhibition abolished the ability of Bcl-2 to increase tumor cell migration and proliferation on high stiffness condition of culture, to stimulate in vitro fibroblasts migration and to induce fibroblasts activation.ConclusionsWe discovered that Bcl-2 regulates the Hippo pathway in different tumor types, promoting cell migration, adaptation to higher stiffness culture condition and fibroblast activation. Our data indicate that Bcl-2 inhibitors should be further investigated to counteract cancer-promoting mechanisms.

Synthesis, characterization, and biological activity of cationic ruthenium-arene complexes with sulfur ligands.

Five cationic ruthenium-arene complexes with the generic formula [Ru(SAc)(S2C·NHC)(p-cymene)](PF6) (5a-e) were prepared in almost quantitative yields using a straightforward one-pot, two-step experimental procedure starting from [RuCl2(p-cymene)]2, an imidazol(in)ium-2-dithiocarboxylate (NHC·CS2) zwitterion, KSAc, and KPF6. These half-sandwich compounds were fully characterized by various analytical techniques and the molecular structures of two of them were solved by X-ray diffraction analysis, which revealed the existence of an intramolecular chalcogen bond between the oxygen atom of the thioacetate ligand and a proximal sulfur atom of the dithiocarboxylate unit. DFT calculations showed that the C=S…O charge transfer amounted to 2.4kcalmol-1. The dissolution of [Ru(SAc)(S2C·IMes)(p-cymene)](PF6) (5a) in moist DMSO-d6 at room temperature did not cause the dissociation of its sulfur ligands. Instead, p-cymene was slowly released to afford the 12-electron [Ru(SAc)(S2C·IMes)]+ cation that could be detected by mass spectrometry. Monitoring the solvolysis process by 1H NMR spectroscopy showed that more than 22days were needed to fully decompose the starting ruthenium-arene complex. Compounds 5a-e exhibited a high antiproliferative activity against human glioma Hs683 and human lung carcinoma A549 cancer cells. In particular, the IMes derivative (5a) was the most potent compound of the series, achieving toxicities similar to those displayed by marketed platinum drugs.

GPS2 ameliorates cigarette smoking-induced pulmonary vascular remodeling by modulating the ras-Raf-ERK axis.

Mitogen-activated protein kinase (MAPK)signaling-mediated smoking-associated pulmonary vascular remodeling (PVR) plays an important role in the pathogenesis of group 3 pulmonary hypertension (PH). And G protein pathway suppressor 2 (GPS2) could suppress G-protein signaling such as Ras and MAPK, but its role in cigarette smoking -induced PVR (CS-PVR) is unclear. An in vivo model of smoke-exposed rats was constructed to assess the role of GPS2 in smoking-induced PH and PVR. In vitro, the effects of GPS2 overexpression and silencing on the function of human pulmonary arterial smooth cells (HPASMCs) and the underlying mechanisms were explored. GPS2 expression was downregulated in rat pulmonary arteries (PAs) and HPASMCs after CS exposure. More importantly, CS-exposed rats with GPS2 overexpression had lower right ventricular systolic pressure (RVSP), right ventricular hypertrophy index (RVHI), and wall thickness (WT%) than those without. And enhanced proliferation and migration of HPASMCs induced by cigarette smoking extract (CSE) can be evidently inhibited by overexpressed GPS2. Besides, GPS2siRNA significantly enhanced the proliferation, and migration of HPASMCs as well as activated Ras and Raf/ERK signaling, while these effects were inhibited by zoledronic acid (ZOL). In addition, GPS2 promoter methylation level in rat PAs and HPASMCs was increased after CS exposure, and 5-aza-2-deoxycytidine (5-aza) inhibited CSE-induced GPS2 hypermethylation and downregulation in vitro. GPS2 overexpression could improve the CS-PVR, suggesting that GPS2 might serve as a novel therapeutic target for PH-COPD in the future.

An AAV capsid reprogrammed to bind human transferrin receptor mediates brain-wide gene delivery.

Developing vehicles that efficiently deliver genes throughout the human central nervous system (CNS) will broaden the range of treatable genetic diseases. We engineered an adeno-associated virus (AAV) capsid, BI-hTFR1, that binds human transferrin receptor (TfR1), a protein expressed on the blood-brain barrier (BBB). BI-hTFR1 was actively transported across human brain endothelial cells and, relative to AAV9, provided 40-50 times greater reporter expression in the CNS of human TFRC knock-in mice. The enhanced tropism was CNS-specific and absent in wild type mice. When used to deliver GBA1, mutations of which cause Gaucher disease and are linked to Parkinson's disease, BI-hTFR1 substantially increased brain and cerebrospinal fluid glucocerebrosidase activity compared to AAV9. These findings establish BI-hTFR1 as a potential vector for human CNS gene therapy.

FRUCTOSE EXACERBATES ANTHRACYCLINE AND HER–2 BLOCKING AGENT MEDIATED CARDIOTOXICITY THROUGH NLRP3 AND MYD88 MEDIATED PATHWAYS: NEW ROLES OF SWEETENERS IN CARDIO–ONCOLOGY

Abstract Background Combinatorial therapy based on anthracyclines and HER–2 blocking agents increases the risk of cardiomyopathy in women with breast cancer. Fructose is a monosaccharide associated with high risk of diabetes, non–alcoholic fatty liver disease, atherosclerosis and visceral obesity. A high fructose diet is a potential cardiometabolic risk factor and may increase cardiac risk in women with breast cancer treated with cardiotoxic drugs. Purpose In this study, we highlighted the role of sweeteners fructose in the worsening of cardiotoxicity induced by combinatorial therapy anthracycline–HER2–blocking agents. Methods Human cardiomyocytes were pre–exposed with doxorubicin combined to trastuzumab (at 300 and 1000 nM) for 48 and 72h alone or combined to fructose at 0.25, 1 and 2.5 mM. After the incubation period, we performed the following tests: determination of cell viability, through mitochondrial dehydrogenase activity, study of lipid peroxidation (quantifying cellular Malondialdehyde and 4–hydroxynonenal), intracellular Ca2+ homeostasis. Moreover, pro–inflammatory studied were also performed (activation of NLRP3 inflammasome; expression of peroxisome proliferator–activated receptor–α; transcriptional activation of p65/NF–κB and secretion of cytokines involved in cardiotoxicity (Interleukins 1β, 8, 6, CXCL–12). Results High fructose increases significantly cell mortality of cardiomyocytes exposed to doxorubicin and trastuzumab thorugh the activation of NLRP–3 and Myd–88 expression. Intracellular Ca++ levels were also increased of 4 times compared to non–fructose exposed cardiomyocytes; MDA and 4–HNA levels were increased of 48,3 and 51,2 % compared to non–fructose exposed cells (p<0.001). Fructose increases IL–1, IL–6 and CXCL–12 expression in cardiomyocytes in a concentration dependent manner, compard to doxorubicin–trastuzumab group (p<0.05). Conclusion Data of the present study indicate that fructose induces a pro–inflammatory phenotype in human cardiac cells exposed to anticancer cardiotoxic drugs, providing even more data on the harmful role of fructose as a key player of cardiotoxic phenomena.

Mussel-Inspired Polymer-Based Coating Technology for Antifouling and Antibacterial Properties.

Zwitterionic coatings provide a promising antifouling strategy against biofouling adhesion. Quaternary ammonium cationic polymers can effectively kill bacteria on the surface, owing to their positive charges. This strategy can avoid the release of toxic biocides, which is highly desirable for constructing coatings for biomedical devices. The present work aims to develop a facile method by covalently grafting zwitterionic and cationic copolymers containing aldehydes to the remaining amine groups of self-polymerized dopamine. Reversible addition-fragmentation chain transfer polymerization was used to copolymerize either zwitterionic 2-methacryloyloxyethyl phosphorylcholine monomer (MPC) or cationic 2-(methacryloyloxy)ethyl trimethylammonium monomer (META) with 4-formyl phenyl methacrylate monomer (FPMA), and the formed copolymers poly(MPC-st-FPMA) and poly(META-st-FPMA) are denoted as MPF and MTF, respectively. MPF and MTF copolymers were then covalently grafted onto the amino groups of polydopamine-coated surfaces. PDA/MPF/MTF-coated surfaces exhibited antibacterial and antifouling properties against S. aureus, E. coli, and bovine serum albumin protein. In addition, they showed excellent viability of normal human lung fibroblast cells MRC-5. We expect the facile surface modification strategy discussed here to be applicable to medical device manufacturing.

Spatial Transcriptomics Reveals Interaction of Injury-Derived Osteopontin with Mesothelial Cells in Serosal Scarring

Abstract Background Abdominal surgeries are often live-saving procedures. However, surgical interventions in the peritoneal cavity can cause the formation of post-surgical adhesions. These irreversible scar bands can trigger severe complications, such as chronic pelvic pain, small bowel obstruction, and infertility in women. Unfortunately, no effective treatment options for adhesion patients exist. On a cellular level, mesothelium-derived mesenchymal myofibroblasts have been identified as key pro-fibrotic players in adhesion formation. Aims Our aim is to study the molecular mechanisms of mesothelial cell recruitment in serosal repair and scarring, and thereby to identify potential targets for specific pharmacological anti-adhesion treatments. Methods We used a mesothelial cell reporter mouse system (Wt1CreERT2xRosa26tdTomato) and experimental injury models to study the differences of mesothelial cell recruitment to sites of adhesion formation in comparison to wound sites healing scar-free. To answer how injury zones affect the accumulation of mesothelial cells, we used untargeted spatial transcriptomics, identifying candidate molecules that were i) upregulated in adhesion formation sites, ii) not highly expressed in scar-free wound sites, and iii) had the potential to interact with mesothelial cells. Results We observed strong spatiotemporal correlation between accumulation of tdTomato+ cells and consecutive scarring. Spatial deconstruction of scar-specific signaling identified the candidate molecule Secreted phosphoprotein 1; an inflammatory zone-specific gene that encodes Osteopontin (OPN). After confirming increased OPN protein levels 7d post-surgery, we investigated its effect on adhesion formation using Spp1-/- mice. Indeed, Spp1-deficient mice showed significantly lower adhesion scores compared to control mice. Mechanistically, recombinant OPN had no chemotactic effect on primary human mesothelial cells, however triggered the upregulation of transcription factors associated with mesothelial-to-mesenchymal transition. Conclusion Together, these findings suggest a pivotal role for OPN in linking inflammation at injury sites with mesothelial cell recruitment in post-surgical serosal scarring. Therefore, OPN represents a potential target for novel pharmacological strategies to specifically inhibit scarring without affecting normal wound repair.

Sequential glycosylations at the multibasic cleavage site of SARS-CoV-2 spike protein regulate viral activity

The multibasic furin cleavage site at the S1/S2 boundary of the spike protein is a hallmark of SARS-CoV-2 and plays a crucial role in viral infection. However, the mechanism underlying furin activation and its regulation remain poorly understood. Here, we show that GalNAc-T3 and T7 jointly initiate clustered O-glycosylations in the furin cleavage site of the SARS-CoV-2 spike protein, which inhibit furin processing, suppress the incorporation of the spike protein into virus-like-particles and affect viral infection. Mechanistic analysis reveals that the assembly of the spike protein into virus-like particles relies on interactions between the furin-cleaved spike protein and the membrane protein of SARS-CoV-2, suggesting a possible mechanism for furin activation. Interestingly, mutations in the spike protein of the alpha and delta variants of the virus confer resistance against glycosylation by GalNAc-T3 and T7. In the omicron variant, additional mutations reverse this resistance, making the spike protein susceptible to glycosylation in vitro and sensitive to GalNAc-T3 and T7 expression in human lung cells. Our findings highlight the role of glycosylation as a defense mechanism employed by host cells against SARS-CoV-2 and shed light on the evolutionary interplay between the host and the virus.

Novel combination of Olesoxime/Resveratrol-encapsulated exosomes to improve cognitive function by targeting amyloid β-induced Alzheimer's disease: investigation on in vitro and in vivo model.

Alzheimer's disease (AD) is a fatal neurological illness that worsens with time. Preventing the aggregate formation of amyloid beta protein is a promising approach to treat Alzheimer's disease. This article describes an amiable procedure for the synthesis of Olesoxime-Resveratrol (OLX-RSV) encapsulated in exosomes. By suppressing Aβ1-42 aggregation and crossing the blood-brain barrier also known as BBB after intravenous treatment without resulting in any discernible damage, the nanocomposite demonstrated good biocompatibility. A variety of characterization technique including particle size, TEM, and in vitro drug release experiments, were used to characterize the exosomes. Human Neuroblastoma (SHSY5Y) cells were used to test the cytotoxicity and viability of cells of the formulation using the Cell Counting Kit-8 assay. The prepared OLX-RSV-loaded exosomes were tested for their ability to suppress Aβ1-42 in SHSY5Y Cells by analyzing the amyloid samples using CD spectra. The effects of apoptosis on Human neuroblastoma cells were studied using cytofluorometry. The parameters of SOD, caspase-3 and the ability to scavenge reactive oxygen species (ROS) were also evaluated. The behavioral outcomes of Morris water maze test demonstrated that OLX-RSV-loaded exosomes significantly enhanced the APP/PS1 mice's capacity to learn and remember spatial cues. Therefore, we hypothesized that OLX-RSV-loaded exosomes could be a useful and efficient method in the treatment of AD.

COMBINATORIAL IMMUNE CHECKPOINT BLOCKADE INCREASES MYOCARDIAL SECRETION OF H–FABP, NT–PRO–BNP, NLRP–3 INFLAMMASOME, INTERLEUKIN–1Β AND INTERLEUKIN–6: BIOCHEMICAL IMPLICATIONS IN CARDIO–IMMUNO–ONCOLOGY

Abstract Background Immune checkpoint blockade have become an integral part of oncology in recent years. Monoclonal antibodies against CTLA–4 or PD–1 or PDL–1 are the most studied ICIs in randomized clinical trials, however, more recently, an anti–LAG3 monoclonal antibody, Relatlimab, has been approved by FDA for combinatorial treatment with Nivolumab for metastatic melanoma. Moreover, anti PD–L1 blocking agent Atezolizumab is actually under study in association with Ipilimumab as innovative thearpy for metastatic lung cancer. Myocarditis, vasculitis and endothelitis are rarely observed in these patients on monotherapy, however new combination therapies and the use of new targets in immunotherapy could expose patients to more adverse cardiovascular events. Purpose In this study, we highlighted the cardiotoxic properties of new Combinatorial immune checkpoint blockade therapies. Methods Human cardiomyocytes co–cultured with human peripheral blood lymphocytes (hPBMCs) were exposed to monotherapy and combinatorial ICIs (PD–L1 and CTLA–4 or PD–1 and LAG–3 blocking agents, at 100 nM) for 48 h. After treatments, cardiac cell lysis and secretion of biomarkers of cardiotoxicity (H–FABP, NT–Pro–BNP), NLRP3–inflammasome and Interleukin 1 and 6 were determined through colorimetric and enzymatic assays. Results Both combinations of immune checkpoint inhibitors exert more potent cardiotoxic side effects compared to monotherapies against human cardiac cells co–cultured with human lymphocytes. LDH release from cardiac cells was 43% higher in PD–L1/CTLA–4 blocking agents, and 35.7% higher in PD–1/LAG–3 blocking agents compared to monotherapies. NT–Pro–BNP and H–FABP, were also strongly increased in combination therapy with respect to monotherapies. NLRP3, IL–6 and IL–1β levels were also increased by PDL–1/CTLA–4 and PD–1/LAG–3 combined blocking agents compared to untreated cells and monotherapies. Conclusion Data of the present study, although in vitro, indicate that combinatorial immune checkpoint blockade, induce a pro– inflammatory phenotype, thus indicating that these therapies should be closely monitored by the multidisciplinary team consisting of oncologists, cardiologists and immunologists.

Endothelial EGLN3-PKM2 signaling induces the formation of acute astrocytic barrier to alleviate immune cell infiltration after subarachnoid hemorrhage.

Most subarachnoid hemorrhage (SAH) patients have no obvious hematoma lesions but exhibit blood-brain barrier dysfunction and vasogenic brain edema. However, there is a few days between blood‒brain barrier dysfunction and vasogenic brain edema. The present study sought to investigate whether this phenomenon is caused by endothelial injury induced by the acute astrocytic barrier, also known as the glial limitans. Bioinformatics analyses of human endothelial cells and astrocytes under hypoxia were performed based on the GEO database. Wild-type, EGLN3 and PKM2 conditional knock-in mice were used to confirm glial limitan formation after SAH. Then, the effect of endothelial EGLN3-PKM2 signaling on temporal and spatial changes in glial limitans was evaluated in both in vivo and in vitro models of SAH. The data indicate that in the acute phase after SAH, astrocytes can form a temporary protective barrier, the glia limitans, around blood vessels that helps maintain barrier function and improve neurological prognosis. Molecular docking studies have shown that endothelial cells and astrocytes can promote glial limitans-based protection against early brain injury through EGLN3/PKM2 signaling and further activation of the PKC/ERK/MAPK signaling pathway in astrocytes after SAH. Improving the ability to maintain glial limitans may be a new therapeutic strategy for improving the prognosis of SAH patients.

Mechanistic insights into SARS-CoV-2 spike protein induction of the chemokine CXCL10

During a SARS-CoV-2 infection, macrophages recognize viral components resulting in cytokine production. While this response fuels virus elimination, overexpression of cytokines can lead to severe COVID-19. Previous studies suggest that the spike protein (S) of SARS-CoV-2 can elicit cytokine production via the transcription factor NF-κB and the toll-like receptors (TLRs). In this study, we found that: (i) S and the S2 subunit induce CXCL10, a chemokine implicated in severe COVID-19, gene expression by human macrophage cells (THP-1); (ii) a glycogen synthase kinase-3 inhibitor attenuates this induction; (iii) S and S2 do not activate NF-κB but do activate the transcription factor IRF; (iv) S and S2 do not require TLR2 to elicit CXCL10 production or activate IRF; and (v) S and S2 elicit CXCL10 production by peripheral blood mononuclear cells (PBMCs). We also discovered that the cellular response, or lack thereof, to S and S2 is a function of the recombinant S and S2 used. While such a finding raises the possibility of confounding LPS contamination, we offer evidence that potential contaminating LPS does not underly induced increases in CXCL10. Combined, these results provide insights into the complex immune response to SARS-CoV-2 and suggest possible therapeutic targets for severe COVID-19.

The role of regulatory T-cells in the development of endometriosis.

Endometriosis is a benign disease of the female reproductive tract, characterized by the process of chronic inflammation and alterations in immune response. It is estimated to affect 2-19% of women in the general population and is commonly associated with symptoms of chronic pelvic pain and infertility. Regulatory T cells (Treg) are a subpopulation of T lymphocytes that are potent suppressors of inflammatory immune response, essential in preventing destructive immunity in all tissues. In endometriosis, several studies have investigated the possible role of Treg cells in the development of the disease. Most studies to date are heterogeneous in methodology and are based on a small number of cases, which means that it is impossible to define their exact role at present. Based on current knowledge, it seems that disturbed Treg homeostasis, leading to increased systemic and local inflammation within ectopic and eutopic endometrium, is present in women who eventually develop endometriosis. It is also evident that different subsets of human Treg cells have different roles in suppressing the immune response. Recent studies in patients with endometriosis have investigated naive/resting FOXP3lowCD45RA+ Treg cells, which upon T cell receptor stimulation, differentiate into activated/effector FOXP3highCD45RA- Treg cells, characterized by a strong immunosuppressive activity. In addition, critical factors controlling expression of Treg/effector genes, including reactive oxygen species and heme-responsive master transcription factor BACH2, were found to be upregulated in endometriotic lesions. As shown recently for cancer microenvironments, microbial inflammation may also contribute to the local composition of FOXP3+ subpopulations in endometriotic lesions. Furthermore, cytokines, such as IL-7, which control the homeostasis of Treg subsets through the tyrosine phosphorylation STAT5 signalling pathway, have also been shown to be dysregulated. To better understand the role of Treg in the development of endometriosis, future studies should use clear definitions of Tregs along with specific characterization of the non-Treg (FOXP3lowCD45RA-) fraction, which itself is a mixture of follicular Tregs and cells producing inflammatory cytokines.

Comparing fabrication techniques for engineered cardiac tissue.

Tissue engineering can provide in vitro models for drug testing, disease modeling, and perhaps someday, tissue/organ replacements. For building 3D heart tissue, the alignment of cardiac cells or cardiomyocytes (CMs) is important in generating a synchronously contracting tissue. To that end, researchers have generated several fabrication methods for building heart tissue, but direct comparisons of pros and cons using the same cell source is lacking. Here, we derived cardiomyocytes (CMs) from human induced pluripotent stem cells (hiPSCs) and compare the assembly of these cells using three fabrication methods: cardiospheres, muscle rings, and muscle strips. All three protocols successfully generated compacted tissue comprised of hiPSC-derived CMs stable for at least 2 weeks. The percentage of aligned cells was greatest in the muscle strip (55%) and the muscle ring (50%) compared with the relatively unaligned cardiospheres (35%). The iPSC-derived CMs within the muscle strip also exhibited the greatest elongation, with elongation factor at 2.0 compared with 1.5 for the muscle ring and 1.2 for the cardiospheres. This is the first direct comparison of various fabrication techniques using the same cell source.

Genome-Wide CRISPR Screen Identifies an NF2-Adherens Junction Mechanistic Dependency for Cardiac Lineage.

Cardiomyocyte differentiation involves a stepwise clearance of repressors and fate-restricting regulators through the modulation of BMP (bone morphogenic protein)/Wnt-signaling pathways. However, the mechanisms and how regulatory roadblocks are removed with specific developmental signaling pathways remain unclear. We conducted a genome-wide CRISPR screen to uncover essential regulators of cardiomyocyte specification in human embryonic stem cells using a myosin heavy chain 6 (MYH6)-GFP (green fluorescence protein) reporter system. After an independent secondary sgRNA validation of 25 candidates, we identified NF2 (neurofibromin 2), a moesin-ezrin-radixin like (MERLIN) tumor suppressor, as an upstream driver of early cardiomyocyte lineage specification. Independent monoclonal NF2 knockouts were generated using CRISPR-Cas9, and cell states were inferred through bulk RNA sequencing and protein expression analysis across differentiation time points. Terminal lineage differentiation was assessed by using an in vitro 2-dimensional-micropatterned gastruloid model, trilineage differentiation, and cardiomyocyte differentiation. Protein interaction and post-translation modification of NF2 with its interacting partners were assessed using site-directed mutagenesis, coimmunoprecipitation, and proximity ligation assays. Transcriptional regulation and trajectory inference from NF2-null cells reveal the loss of cardiomyocyte identity and the acquisition of nonmesodermal identity. Sustained elevation of early mesoderm lineage repressor SOX2 and upregulation of late anticardiac regulators CDX2 and MSX1 in NF2 knockout cells reflect a necessary role for NF2 in removing regulatory roadblocks. Furthermore, we found that NF2 and AMOT (angiomotin) cooperatively bind to YAP (yes-associated protein) during mesendoderm formation, thereby preventing YAP activation, independent of canonical MST (mammalian sterile 20-like serine-threonine protein kinase)-LATS (large tumor suppressor serine-threonine protein kinase) signaling. Mechanistically, cardiomyocyte lineage identity was rescued by wild-type and NF2 serine-518 phosphomutants, but not NF2 FERM (ezrin-radixin-meosin homology protein) domain blue-box mutants, demonstrating that the critical FERM domain-dependent formation of the AMOT-NF2-YAP scaffold complex at the adherens junction is required for early cardiomyocyte lineage differentiation. These results provide mechanistic insight into the essential role of NF2 during early epithelial-mesenchymal transition by sequestering the repressive effect of YAP and relieving regulatory roadblocks en route to cardiomyocytes.

Nuclear export is a limiting factor in eukaryotic mRNA metabolism.

The eukaryotic mRNA life cycle includes transcription, nuclear mRNA export and degradation. To quantify all these processes simultaneously, we perform thiol-linked alkylation after metabolic labeling of RNA with 4-thiouridine (4sU), followed by sequencing of RNA (SLAM-seq) in the nuclear and cytosolic compartments of human cancer cells. We develop a model that reliably quantifies mRNA-specific synthesis, nuclear export, and nuclear and cytosolic degradation rates on a genome-wide scale. We find that nuclear degradation of polyadenylated mRNA is negligible and nuclear mRNA export is slow, while cytosolic mRNA degradation is comparatively fast. Consequently, an mRNA molecule generally spends most of its life in the nucleus. We also observe large differences in the nuclear export rates of different 3'UTR transcript isoforms. Furthermore, we identify genes whose expression is abruptly induced upon metabolic labeling. These transcripts are exported substantially faster than average mRNAs, suggesting the existence of alternative export pathways. Our results highlight nuclear mRNA export as a limiting factor in mRNA metabolism and gene regulation.

Subminute thermal damage to cell types present in the skin

Introduction Psoriasis is characterized by an increase in the proliferation of keratinocytes and nerve fiber activity, contributing to the typical skin lesions. Pulsed Dye Laser (PDL) treatment is effective for the treatment of psoriatic lesions but its mechanism remains unclear. One hypothesis is that PDL causes thermal damage by the diffusion of heat to neighboring structures in lesional skin. There is limited information on the thermal sensitivity of these neighboring skin cells when exposed to hyperthermia for durations lasting less than a minute. Our study aimed to investigate the cell-specific responses to heat using sub-minute exposure times and moderate to ablative hyperthermia. Materials and Methods Cultured human endothelial cells, smooth muscle cells, neuronal cells, and keratinocytes were exposed to various time (2–20 sec) and temperature (45–70 °C) combinations. Cell viability was assessed by measuring intracellular ATP content 24 h after thermal exposure and this data was used to calculate fit parameters for the Arrhenius model and CEM43 calculations. Results Our results show significant differences in cell survival between cell types (p < 0.0001). Especially within the range of 50–60 °C, survival of neuronal cells and keratinocytes was significantly less than that of endothelial and smooth muscle cells. No statistically significant difference was found in the lethal dose (LT50) of thermal energy between neuronal cells and keratinocytes. However, CEM43 calculations showed significant differences between all four cell types. Conclusion The results imply that there is a cell-type-dependent sensitivity to thermal damage which suggests that neuronal cells and keratinocytes are particularly susceptible to diffusing heat from laser treatment. Damage to these cells may aid in modulating the neuro-inflammatory pathways in psoriasis. These data provide insight into the potential mechanisms of PDL therapy for psoriasis and advance our understanding of how thermal effects may play a role in its effectiveness.

Extracellular vesicles from senescent mesenchymal stromal cells are defective and cannot prevent osteoarthritis.

Age is the most important risk factor in degenerative diseases such as osteoarthritis (OA), which is associated with the accumulation of senescent cells in the joints. Here, we aimed to assess the impact of senescence on the therapeutic properties of extracellular vesicles (EVs) from human fat mesenchymal stromal cells (ASCs) in OA. We generated a model of DNA damage-induced senescence in ASCs using etoposide and characterized EVs isolated from their conditioned medium (CM). Senescent ASCs (S-ASCs) produced 3-fold more EVs (S-EVs) with a slightly bigger size and that contain 2-fold less total RNA. Coculture experiments showed that S-ASCs were as efficient as healthy ASCs (H-ASCs) in improving the phenotype of OA chondrocytes cultured in resting conditions but were defective when chondrocytes were proliferating. S-EVs were also impaired in their capacity to polarize synovial macrophages towards an anti-inflammatory phenotype. A differential protein cargo mainly related to inflammation and senescence was detected in S-EVs and H-EVs. Using the collagenase-induced OA model, we found that contrary to H-EVs, S-EVs could not protect mice from cartilage damage and joint calcifications, and were less efficient in protecting subchondral bone degradation. In addition, S-EVs induced a pro-catabolic and pro-inflammatory gene signature in the joints of mice shortly after injection, while H-EVs decreased hypertrophic, catabolic and inflammatory pathways. In conclusion, S-EVs are functionally impaired and cannot protect mice from developing OA.

Nerolidol Alleviates Oxidative Stress and Inflammation in Diabetic Retinopathy Mediated by High Glucose Through Ameliorating Nrf2/HO-1 Pathway

Background Diabetic retinopathy (DR) is the foremost microvascular problem that causes drastic visual impairment in diabetes patients. Hyperglycemia-triggered reaction cascade of inflammation and oxidative stress constitute the DR pathogenesis. The existing treatment options are not completely satisfactory. Materials and Methods We investigated the cell viability by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, inflammatory mediators, lactate dehydrogenase (LDH), superoxide dismutase, glutathione, and malonaldehyde (MDA) levels by ELISA and qRT-PCR assay, protein expression of Nrf2 and heme oxygenase-1 (HO-1) by western blotting assay were analyzed. Results According to our research, nerolidol (NRD) increases the proliferation and antioxidant activity of human retinal endothelial cells (HRECs) by inducing Nrf2/HO-1 signaling, while attenuating MDA, an oxidative stress marker, LDH, and inflammatory mediators. These outcomes suggest that a substantial reaction of inflammation and oxidative stress injury happened in DR, which might be correlated to the instigation of the signaling Nrf2/HO-1. Conclusion NRD effectively suppresses oxidative stress and inflammation in HG-induced HRECs. The primary mechanism of NRD on DR may be linked to the activation of the Nrf2/HO-1 pathway and may give a useful medicine for DR treatment.