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The ectopic expression of the transcription factors OCT4, SOX2, KLF4 and MYC (OSKM) enables reprogramming of differentiated cells into pluripotent embryonic stem cells. Methods based on partial and reversible in vivo reprogramming are a promising strategy for tissue regeneration and rejuvenation. However, little is known about the barriers that impair reprogramming in an in vivo context. We report that natural killer (NK) cells significantly limit reprogramming, both in vitro and in vivo. Cells and tissues in the intermediate states of reprogramming upregulate the expression of NK-activating ligands, such as MULT1 and ICAM1. NK cells recognize and kill partially reprogrammed cells in a degranulation-dependent manner. Importantly, in vivo partial reprogramming is strongly reduced by adoptive transfer of NK cells, whereas it is significantly increased by their depletion. Notably, in the absence of NK cells, the pancreatic organoids derived from OSKM-expressing mice are remarkably large, suggesting that ablating NK surveillance favours the acquisition of progenitor-like properties. We conclude that NK cells pose an important barrier for in vivo reprogramming, and speculate that this concept may apply to other contexts of transient cellular plasticity. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether HCWs return to work (RTW) after COVID-19 was associated with time to a negative viral detection test. Methods: To evaluate the association of RTW with an undetectable RT-PCR adjusting for different factors. Results: Three hundred seventy-five HCWs who required medical leave for COVID-19 at a hospital in Madrid. Multivariable analyses confirmed the association of delayed RTW with interval to negative PCR (ORadj 1.12, 95% CI 1.08, 1.17) as well as age, sex, and nursing staff and clinical support services compared to physicians. A predictive model based on those variables is proposed, which had an area under the receiver operating curve of 0.82. Conclusions: Delayed RTW was associated with longer interval to a negative RT-PCR after symptom onset, adjusting for occupational category, age, and sex. [ABSTRACT FROM AUTHOR]

Background: The ubiquitin-proteasome-system (UPS) is the major intracellular pathway leading to the degradation of unwanted and/or misfolded soluble proteins. This includes proteins regulating cellular survival, synaptic plasticity and neurotransmitter signaling; processes controlling excitability thresholds that are altered by epileptogenic insults. Dysfunction of the UPS has been reported to occur in a brain region- and cell-specific manner and contribute to disease progression in acute and chronic brain diseases. Prolonged seizures, status epilepticus, may alter UPS function but there has been no systematic attempt to map when and where this occurs in vivo or to determine the consequences of proteasome inhibition on seizure-induced brain injury. Method: To determine whether seizures lead to an impairment of the UPS, we used a mouse model of status epilepticus whereby seizures are triggered by an intra-amygdala injection of kainic acid. Status ilepticus in this model causes cell death in selected brain areas, in particular the ipsilateral CA3 subfield of the hippocampus, and the development of epilepsy after a short latent period. To monitor seizure-induced sfunction of the UPS we used a UPS inhibition reporter mouse expressing the ubiquitin fusion degradation substrate ubiquitinG76V-green fluorescent protein. Treatment with the specific proteasome inhibitorepoxomicin was used to establish the impact of proteasome inhibition on seizure-induced pathology. Results and conclusions: Our studies show that status epilepticus induced by intra-amygdala kainic acid causes select spatio-temporal UPS inhibition which is most evident in damage-resistant regions of the hippocampus, including CA1 pyramidal and dentate granule neurons then appears later in astrocytes. In support of this exerting a beneficial effect, injection of mice with the proteasome inhibitor epoxomicin protected the normally vulnerable hippocampal CA3 subfield from seizure-induced neuronal death in the model. These studies reveal brain region- and cell-specific UPS impairment occurs after seizures and suggest UPS inhibition can protect against seizure-induced brain damage. Identifying networks or pathways regulated through the proteasome after seizures may yield novel target genes for the treatment of seizure-induced cell death and possibly epilepsy. [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted to assess the three dimensional anatomy of the Lisfranc ligament and its attachment sites. Researchers evaluated 37 cadaver feet that were dissected to expose the ligament attachments at the Lisfranc joint.They found that the Lisfranc ligament is variable in anatomy and can have a single or double-bundle arrangement and that its area of attachment is larger than that of the plantar ligament.

The glycine transporter GLYT1 regulates both glycinergic and glutamatergic neurotransmission by controlling the reuptake of glycine at synapses. Trafficking of GLYT1 to and from the cell surface is critical for its function. Activation of PKC down-regulates the activity of GLYT1 through a mechanism that has so far remained uncharacterized. Here we show that GLYT1b undergoes fast constitutive endocytosis that is accelerated by phorbol esters. Both constitutive and regulated endocytosis occur through a dynamin 2and clathrin-dependent pathway, accumulating in the transporter in transferrin-containing endosomes. A chimera with the extracellular and transmembrane domains of the nerve growth factor receptor and the COOH-terminal tail of GLYT1 was efficiently internalized through this clathrin pathway, suggesting the presence of molecular determinants for GLYT1b endocytosis in its COOH-terminal tail. Extensive site-directed mutagenesis in this region of the chimera highlighted the involvement of lysine residues in its internalization. In the context of the full-length transporter, lysine 619 played a prominent role in both the constitutive and phorbol 12-myristate 13-acetate-induced endocytosis of GLYT1b, suggesting the involvement of ubiquitin modification of GLYT1b during the internalization process. Indeed, we show that GLYT1b undergoes ubiquitination and that this process is stimulated by phorbol 12-myristate 13-acetate. In addition, this endocytosis is impaired in an ubiquitination-deficient cell line, further evidence that constitutive and regulated endocytosis of GLYT1b is ubiquitin-dependent. It remains to be determined whether GLYT1b recycling might be affected in pathologies involving alterations to the ubiquitin system, thereby interfering with its influence on inhibitory and excitatory neurotransmission. [ABSTRACT FROM AUTHOR]

Understanding urothelial stem cell biology and differentiation has been limited by the lack of methods for their unlimited propagation. Here, we establish mouse urothelial organoids that can be maintained uninterruptedly for >1 year. Organoid growth is dependent on EGF and Wnt activators. High CD49f/ITGA6 expression features a subpopulation of organoid-forming cells expressing basal markers. Upon differentiation, multilayered organoids undergo reduced proliferation, decreased cell layer number, urothelial program activation, and acquisition of barrier function. Pharmacological modulation of PPARγ and EGFR promotes differentiation. RNA sequencing highlighted genesets enriched in proliferative organoids (i.e. ribosome) and transcriptional networks involved in differentiation, including expression of Wnt ligands and Notch components. Single-cell RNA sequencing (scRNA-Seq) analysis of the organoids revealed five clusters with distinct gene expression profiles. Together with the use of γ-secretase inhibitors, scRNA-Seq confirms that Notch signaling is required for differentiation. Urothelial organoids provide a powerful tool to study cell regeneration and differentiation. The biology of the urothelium has been difficult to study given the lack of methods to propagate these cells. Here, the authors generate mouse urothelial organoids derived from bladder urothelial cells with high CD49f/ITGA6 and define what regulates urothelium differentiation, which is PPARγ, EGFR and Notch signalling. [ABSTRACT FROM AUTHOR]

Hyperekplexia or startle disease is characterized by an exaggerated startle response, evoked by tactile or auditory stimuli, producing hypertonia and apnea episodes. Although rare, this orphan disorder can have serious consequences, including sudden infant death. Dominant and recessive mutations in the human glycine receptor (GlyR) α1 gene (GLRA1) are the major cause of this disorder. However, recessive mutations in the presynaptic Na+/Cl--dependent glycine transporter GlyT2 gene (SLC6A5) are rapidly emerging as a second major cause of startle disease. In this study, systematic DNA sequencing of SLC6A5 revealed a new dominant GlyT2 mutation: pY705C (c.2114A→G) in transmembrane domain 11, in eight individuals from Spain and the United Kingdom. Curiously, individuals harboring this mutation show significant variation in clinical presentation. In addition to classical hyperekplexia symptoms, some individuals had abnormal respiration, facial dysmorphism, delayed motor development, or intellectual disability. We functionally characterized this mutation using molecular modeling, electrophysiology, [3H]glycine transport, cell surface expression, and cysteine labeling assays. We found that the introduced cysteine interacts with the cysteine pair Cys-311- Cys-320 in the second external loop of GlyT2. This interaction impairs transporter maturation through the secretory pathway, reduces surface expression, and inhibits transport function. Additionally, Y705C presents altered H+ and Zn2+ dependence of glycine transport that may affect the function of glycinergic neurotransmission in vivo. [ABSTRACT FROM AUTHOR]

Glutamate transporter-1 (GLT-1) is the main glutamate transporter in the central nervous system, and its concentration severely decreases in neurodegenerative diseases. The number of transporters in the plasma membrane reflects the balance between their insertion and removal, and it has been reported that the regulated endocytosis of GLT-1 depends on its ubiquitination triggered by protein kinase C (PKC) activation. Here, we identified serine 520 of GLT-1 as the primary target for PKC-dependent phosphorylation, although elimination of this serine did not impair either GLT-1 ubiquitination or endocytosis in response to phorbol esters. In fact, we present evidence indicating that the ubiquitin ligase Nedd4-2 mediates the PKC-dependent ubiquitination and down-regulation of GLT-1. Overexpression of Nedd4-2 increased the ubiquitination of the transporter and promoted its degradation. Moreover, phorbol myristate acetate enhanced Nedd4-2 phosphorylation and the formation of GLT-1_Nedd4-2 complexes, whereas siRNA knockdown of Nedd4-2 prevented ubiquitination, endocytosis, and the concomitant decrease in GLT-1 activity triggered by PKCactivation. These results indicate that GLT-1 endocytosis is independent of its phosphorylation and that Nedd4-2 mediates PKC-dependent down-regulation of the transporter. [ABSTRACT FROM AUTHOR]

Objective: Genome wide association studies have identified an exon 6 CTRB2 deletion variant that associates with increased risk of pancreatic cancer. To acquire evidence on its causal role, we developed a new mouse strain carrying an equivalent variant in Ctrb1 , the mouse orthologue of CTRB2 ., Design: We used CRISPR/Cas9 to introduce a 707bp deletion in Ctrb1 encompassing exon 6 ( Ctrb1 Δexon6 ). This mutation closely mimics the human deletion variant. Mice carrying the mutant allele were extensively profiled at 3 months to assess their phenotype., Results: Ctrb1 Δexon6 mutant mice express a truncated CTRB1 that accumulates in the ER. The pancreas of homozygous mutant mice displays reduced chymotrypsin activity and total protein synthesis. The histological aspect of the pancreas is inconspicuous but ultrastructural analysis shows evidence of dramatic ER stress and cytoplasmic and nuclear inclusions. Transcriptomic analyses of the pancreas of mutant mice reveals acinar program down-regulation and increased activity of ER stress-related and inflammatory pathways. Heterozygous mice have an intermediate phenotype. Agr2 is one of the most up-regulated genes in mutant pancreata. Ctrb1 Δexon6 mice exhibit impaired recovery from acute caerulein-induced pancreatitis. Administration of TUDCA or sulindac partially alleviates the phenotype. A transcriptomic signature derived from the mutant pancreata is significantly enriched in normal human pancreas of CTRB2 exon 6 deletion variant carriers from the GTEx cohort., Conclusions: This mouse strain provides formal evidence that the Ctrb1 Δexon6 variant causes ER stress and inflammation in vivo , providing an excellent model to understand its contribution to pancreatic ductal adenocarcinoma development and to identify preventive strategies., Summary Box: What is already known about this subject?: - CTRB2 is one of the most abundant proteins produced by human pancreatic acinar cells. - A common exon 6 deletion variant in CTRB2 has been associated with an increased risk of pancreatic ductal adenocarcinoma. - Misfolding of digestive enzymes is associated with pancreatic pathology. What are the new findings?: - We developed a novel genetic model that recapitulates the human CTRB2 deletion variant in the mouse orthologue, Ctrb1 . - Truncated CTRB1 misfolds and accumulates in the ER; yet, mutant mice display a histologically normal pancreas at 3 months age.- CTRB1 and associated chaperones colocalize in the ER, the cytoplasm, and the nucleus of acinar cells.- Transcriptomics analysis reveals reduced activity of the acinar program and increased activity of pathways involved in ER stress, unfolded protein response, and inflammation.- Mutant mice are sensitized to pancreatic damage and do not recover properly from a mild caerulein-induced pancreatitis.- TUDCA administration partially relieves the ER stress in mutant mice. How might it impact on clinical practice in the foreseeable future?: - The new mouse model provides a tool to identify the mechanisms leading to increased pancreatic cancer risk in CTRB2 exon 6 carriers. - The findings suggest that drugs that cause ER stress relief and/or reduce inflammation might provide preventive opportunities.

Bladder cancer is a highly prevalent tumor, requiring the urgent development of novel therapies, especially for locally advanced and metastatic disease. Nintedanib is a potent antifibrotic angio-kinase inhibitor, which has shown clinical efficacy in combination with chemotherapy in patients with locally advanced muscle-invasive bladder cancer. Nintedanib inhibits fibroblast growth factor receptors (FGFRs), validated targets in patients with bladder cancer harboring FGFR3/2 genetic alterations. Here, we aimed at studying its mechanisms of action to understand therapy resistance, identify markers predictive of response, and improve the design of future clinical trials. We have used a panel of genetically well-characterized human bladder cancer cells to identify the molecular and transcriptomic changes induced upon treatment with nintedanib, in vitro and in vivo, at the tumor and stroma cell levels. We showed that bladder cancer cells display an intrinsic resistance to nintedanib treatment in vitro, independently of their FGFR3 status. However, nintedanib has higher antitumor activity on mouse xenografts. We have identified PI3K activation as a resistance mechanism against nintedanib in bladder cancer and evidenced that the combination of nintedanib with the PI3K inhibitor alpelisib has synergistic antitumor activity. Treatment with this combination is associated with cell-cycle inhibition at the tumoral and stromal levels and potent nontumor cell autonomous effects on α-smooth muscle actin-positive tumor infiltrating cells and tumor vasculature. The combination of nintedanib with PI3K inhibitors not only reversed bladder cancer resistance to nintedanib but also enhanced its antiangiogenic effects., (©2023 American Association for Cancer Research.)

Motivation: Transposable elements (TE) have played a major role in configuring the structures of mammalian genomes through evolution. In normal conditions, the expression of these elements is repressed by different epigenetic regulation mechanisms such as DNA methylation, histone modification and regulation by small RNAs. TE re-activation is associated with stemness potential acquisition, regulation of innate immunity and disease, such as cancer. However, the vast majority of current knowledge in the field is based on bulk expression studies, and very little is known on cell-type- or state-specific expression of TE-derived transcripts. Therefore, cost-efficient single-cell-resolution TE expression analytical approaches are needed., Results: We have implemented an analytical approach based on pseudoalignment to consensus sequences to incorporate TE expression information to scRNAseq data., Availability and Implementation: All the data and code implemented are available as Supplementary data and in: https://github.com/jmzvillarreal/kallisto_TE_scRNAseq., Supplementary Information: Supplementary data are available at Bioinformatics online., (© The Author(s) 2022. Published by Oxford University Press.)

Differentiated cells can be converted into pluripotent stem cells by expressing the transcription factors OCT4, SOX2, KLF4, and MYC (OSKM) in a process known as reprogramming. Here, using single-cell RNA sequencing of pancreas undergoing reprogramming, we identify markers along the trajectory from acinar cell identity to pluripotency. These markers allow direct in situ visualization of cells undergoing dedifferentiation and acquiring features of early and advanced intermediate reprogramming. We also find that a fraction of cells do not dedifferentiate upon OSKM expression and are characterized by stress markers of the REG3 and AP-1 families. Importantly, most markers of intermediate reprogramming in the pancreas are also observed in stomach, colon, and cultured fibroblasts expressing OSKM. Among them is LY6A, a protein characteristic of progenitor cells and generally upregulated during tissue repair. Our roadmap defines intermediate reprogramming states that could be functionally relevant for tissue regeneration and rejuvenation., Competing Interests: Conflict of interests M.S. is shareholder and advisor of Senolytic Therapeutics, Inc., Life Biosciences, Inc, Rejuveron Senescence Therapeutics, AG, and Altos Labs, Inc. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: VCN-01 is an oncolytic adenovirus (Ad5 based) designed to replicate in cancer cells with dysfunctional RB1 pathway, express hyaluronidase to enhance virus intratumoral spread and facilitate chemotherapy and immune cells extravasation into the tumor. This phase I clinical trial was aimed to find the maximum tolerated dose/recommended phase II dose (RP2D) and dose-limiting toxicity (DLT) of the intravenous delivery of the replication-competent VCN-01 adenovirus in patients with advanced cancer., Methods: Part I: patients with advanced refractory solid tumors received one single dose of VCN-01. Parts II and III: patients with pancreatic adenocarcinoma received VCN-01 (only in cycle 1) and nab-paclitaxel plus gemcitabine (VCN-concurrent on day 1 in Part II, and 7 days before chemotherapy in Part III). Patients were required to have anti-Ad5 neutralizing antibody (NAbs) titers lower than 1/350 dilution. Pharmacokinetic and pharmacodynamic analyses were performed., Results: 26% of the patients initially screened were excluded based on high NAbs levels. Sixteen and 12 patients were enrolled in Part I and II, respectively: RP2D were 1×10 13 viral particles (vp)/patient (Part I), and 3.3×10 12 vp/patient (Part II). Fourteen patients were included in Part III: there were no DLTs and the RP2D was 1×10 13 vp/patient. Observed DLTs were grade 4 aspartate aminotransferase increase in one patient (Part I, 1×10 13  vp), grade 4 febrile neutropenia in one patient and grade 5 thrombocytopenia plus enterocolitis in another patient (Part II, 1×10 13  vp). In patients with pancreatic adenocarcinoma overall response rate were 50% (Part II) and 50% (Part III). VCN-01 viral genomes were detected in tumor tissue in five out of six biopsies (day 8). A second viral plasmatic peak and increased hyaluronidase serum levels suggested replication after intravenous injection in all patients. Increased levels of immune biomarkers (interferon-γ, soluble lymphocyte activation gene-3, interleukin (IL)-6, IL-10) were found after VCN-01 administration., Conclusions: Treatment with VCN-01 is feasible and has an acceptable safety. Encouraging biological and clinical activity was observed when administered in combination with nab-paclitaxel plus gemcitabine to patients with pancreatic adenocarcinoma., Trial Registration Number: NCT02045602., Competing Interests: Competing interests: MB-P, MF-S, AM-B, MVM, EB, CB and MC are employees, and RS is consultant for VCN Biosciences. MC and RAle are co-inventors of one patent application concerning the expression of hyaluronidase by oncolytic adenoviruses and both have ownership interest in VCN Biosciences. RG-C has provided scientific advice and/or received honoraria or funding for continuous medical education from AAA, Advanz Pharma, Amgen, Bayer, BMS, HMP, Ipsen, Merck, Midatech Pharma, MSD, Novartis, PharmaMar, Pfizer, Pierre Fabre, Roche, Servier and Sanofi, and has received research support from Pfizer, BMS and MSD., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Among malignant mesotheliomas (MM), the sarcomatoid subtype is associated with higher chemoresistance and worst survival. Due to its low incidence, there has been little progress in the knowledge of the molecular mechanisms associated with sarcomatoid MM, which might help to define novel therapeutic targets. In this work, we show that loss of PTEN expression is frequent in human sarcomatoid MM and PTEN expression levels are lower in sarcomatoid MM than in the biphasic and epithelioid subtypes. Combined Pten and Trp53 deletion in mouse mesothelium led to nonepithelioid MM development. In Pten;Trp53 -null mice developing MM, the Gαi2-coupled receptor subunit activated MEK/ERK and PI3K, resulting in aggressive, immune-suppressed tumors. Combined inhibition of MEK and p110β/PI3K reduced mouse tumor cell growth in vitro . Therapeutic inhibition of MEK and p110β/PI3K using selumetinib (AZD6244, ARRY-142886) and AZD8186, two drugs that are currently in clinical trials, increased the survival of Pten ; Trp53 -null mice without major toxicity. This drug combination effectively reduced the proliferation of primary cultures of human pleural (Pl) MM, implicating nonepithelioid histology and high vimentin, AKT1/2, and Gαi2 expression levels as predictive markers of response to combined MEK and p110β/PI3K inhibition. Our findings provide a rationale for the use of selumetinib and AZD8186 in patients with MM with sarcomatoid features. This constitutes a novel targeted therapy for a poor prognosis and frequently chemoresistant group of patients with MM, for whom therapeutic options are currently lacking. SIGNIFICANCE: Mesothelioma is highly aggressive; its sarcomatoid variants have worse prognosis. Building on a genetic mouse model, a novel combination therapy is uncovered that is relevant to human tumors., (©2020 American Association for Cancer Research.)