Natural killer cells act as an extrinsic barrier for in vivo reprogramming.

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.

Pseudoalignment tools as an efficient alternative to detect repeated transposable elements in scRNAseq data.

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.

Integrating socioeconomic and ecological data into restoration practice.

Driven by the United Nations Decade on Restoration and international funding initiatives, such as the Mangrove Breakthrough, investment in mangrove restoration is expected to increase. Yet, mangrove restoration efforts frequently fail, usually because of ad hoc site-selection processes that do not consider mangrove ecology and the socioeconomic context. Using decision analysis, we developed an approach that accounts for socioeconomic and ecological data to identify sites with the highest likelihood of mangrove restoration success. We applied our approach in the Biosphere Reserve Marismas Nacionales Nayarit, Mexico, an area that recently received funding for implementing mangrove restoration actions. We identified 468 potential restoration sites, assessed their restorability potential based on socioeconomic and ecological metrics, and ranked sites for implementation with spatial optimization. The metrics we used included favorable conditions for propagules to establish and survive under sea-level rise, provision of ecosystem services, and community dynamics. Sites that were selected based on socioeconomic or ecological metrics alone had lower likelihood of mangrove restoration success than sites that were selected based on integrated socioeconomic and ecological metrics. For example, selecting sites based on only socioeconomic metrics captured 16% of the maximum attainable value of functioning mangroves able to provide propagules to potential restoration sites, whereas selecting sites based on ecological and socioeconomic metrics captured 46% of functioning mangroves. Our approach was developed as part of a collaboration between nongovernmental organizations, local government, and academics under rapid delivery time lines given preexisting mangrove restoration implementation commitments. The systematic decision process we used integrated socioeconomic and ecological considerations even under short delivery deadlines, and our approach can be adapted to help mangrove restoration site-selection decisions elsewhere.

Integración de datos socioeconómicos y ecológicos en las prácticas de restauración Resumen Se espera que la inversión en la restauración de los manglares incremente debido a la Década de Restauración de las Naciones Unidad y las iniciativas internacionales de financiamiento, como The Mangrove Breakthrough. Sin embargo, los esfuerzos de restauración de manglares fallan con frecuencia, generalmente por los procesos de selección de sitios ad­hoc que no consideran la ecología del manglar y el contexto socioeconómico. Usamos el análisis de decisiones para desarrollar una estrategia que considera los datos socioeconómicos y ecológicos para identificar los sitios con mayor probabilidad de éxito de restauración. Aplicamos nuestra estrategia en la Reserva de la Biósfera Marismas Nacionales Nayarit, México, un área que recibió financiamiento reciente para la restauración del manglar. Identificamos 468 sitios potencialmente restaurables, evaluamos su potencial de restauración con base en medidas ecológicas y socioeconómicas y clasificamos los sitios para la implementación con la optimización espacial. Las medidas que usamos incluían las condiciones favorables para que los propágulos se establezcan y sobrevivan con el incremento en el nivel del mar, el suministro de servicios ambientales y las dinámicas de la comunidad. Los sitios seleccionados sólo con base en las medidas ecológicas o socioeconómicas tuvieron una menor probabilidad de éxito de restauración que los sitios que se seleccionaron con base en medidas socioeconómicas y ecológicas integradas. Por ejemplo, la selección de sitios con base sólo en las medidas socioeconómicas capturó el 16% del máximo valor alcanzable de manglares funcionales capaces de proporcionar propágulos a los sitios potenciales de restauración, mientras que la selección basada en medidas ecológicas y socioeconómicas capturó el 46% de los manglares funcionales. Desarrollamos nuestra estrategia como parte de una colaboración entre organizaciones no gubernamentales, el gobierno local y académicos sujetos a una fecha pronta de entrega debido a los compromisos preexistentes para la restauración de manglares. El proceso de decisión sistemática que usamos integró las consideraciones ecológicas y socioeconómicas incluso con plazos cortos de entrega. Nuestra estrategia puede adaptarse para apoyar en la selección de sitios de restauración de manglares en otros sitios.

A GATA6-centred gene regulatory network involving HNFs and ΔNp63 controls plasticity and immune escape in pancreatic cancer.

OBJECTIVE: Molecular taxonomy of tumours is the foundation of personalised medicine and is becoming of paramount importance for therapeutic purposes. Four transcriptomics-based classification systems of pancreatic ductal adenocarcinoma (PDAC) exist, which consistently identified a subtype of highly aggressive PDACs with basal-like features, including ΔNp63 expression and loss of the epithelial master regulator GATA6. We investigated the precise molecular events driving PDAC progression and the emergence of the basal programme. DESIGN: We combined the analysis of patient-derived transcriptomics datasets and tissue samples with mechanistic experiments using a novel dual-recombinase mouse model for Gata6 deletion at late stages of KRasG12D-driven pancreatic tumorigenesis (Gata6LateKO). RESULTS: This comprehensive human-to-mouse approach showed that GATA6 loss is necessary, but not sufficient, for the expression of ΔNp63 and the basal programme in patients and in mice. The concomitant loss of HNF1A and HNF4A, likely through epigenetic silencing, is required for the full phenotype switch. Moreover, Gata6 deletion in mice dramatically increased the metastatic rate, with a propensity for lung metastases. Through RNA-Seq analysis of primary cells isolated from mouse tumours, we show that Gata6 inhibits tumour cell plasticity and immune evasion, consistent with patient-derived data, suggesting that GATA6 works as a barrier for acquiring the fully developed basal and metastatic phenotype. CONCLUSIONS: Our work provides both a mechanistic molecular link between the basal phenotype and metastasis and a valuable preclinical tool to investigate the most aggressive subtype of PDAC. These data, therefore, are important for understanding the pathobiological features underlying the heterogeneity of pancreatic cancer in both mice and human.

Contribution of BRCA1 and BRCA2 germline mutations to early onset breast cancer: a series from north of Morocco.

BACKGROUND: To date, the contribution of BRCA1/2 mutations in Moroccan early onset breast cancer patients remains unknown. Here we assess these genetic alterations for the first time in a cohort from North of Morocco. METHODS: Thirty-three patients diagnosed with breast cancer at the age of ≤40 years were recruited irrespective of breast and/or ovarian cancer family history. Coding regions and intron-exon boundaries of BRCA1 and BRCA2 genes were sequenced from peripheral blood DNA using Ion Proton (Thermo Fisher Scientific) next generation sequencing platform. RESULTS: Overall, five BRCA germline mutations were identified (15.1%). The frequency of mutations among patients with family history of breast cancer was 16.7%. Three mutations were found in BRCA1 (9%) and two within the BRCA2 gene (6%). These are three frameshift mutations (c.798_799del, c.2125_2126insA, c.5116_5119delAATA), one missense (c.116G > A) and one nonsense mutation (c.289G > T). The mutation c.5116_5119delAATA has a founder effect in North Africa. Moreover, one variant of unknown significance was identified in BRCA2 (c.4090A > G). Most BRCA mutations carriers (80%) had no family history of breast cancer. CONCLUSION: Our data do not support the hypothesis that BRCA mutations alone explain the higher frequency of breast cancer in Moroccan young women. The young age (≤40 years) for breast cancer diagnosis seems to be strongly predictive of BRCA mutation status in Moroccan patients. These results will help in decision making with regard to genetic counseling and testing in the national scale.

Vitamin D opposes multilineage cell differentiation induced by Notch inhibition and BMP4 pathway activation in human colon organoids.

Understanding the mechanisms involved in colonic epithelial differentiation is key to unraveling the alterations causing inflammatory conditions and cancer. Organoid cultures provide an unique tool to address these questions but studies are scarce. We report a differentiation system toward enterocytes and goblet cells, the two major colonic epithelial cell lineages, using colon organoids generated from healthy tissue of colorectal cancer patients. Culture of these organoids in medium lacking stemness agents resulted in a modest ultrastructural differentiation phenotype with low-level expression of enterocyte (KLF4, KRT20, CA1, FABP2) and goblet cell (TFF2, TFF3, AGR2) lineage markers. BMP pathway activation through depletion of Noggin and addition of BMP4 resulted in enterocyte-biased differentiation. Contrarily, blockade of the Notch pathway using the γ-secretase inhibitor dibenzazepine (DBZ) favored goblet cell differentiation. Combination treatment with BMP4 and DBZ caused a balanced strong induction of both lineages. In contrast, colon tumor organoids responded poorly to BMP4 showing only weak signals of cell differentiation, and were unresponsive to DBZ. We also investigated the effects of 1α,25-dihydroxyvitamin D3 (calcitriol) on differentiation. Calcitriol attenuated the effects of BMP4 and DBZ on colon normal organoids, with reduced expression of differentiation genes and phenotype. Consistently, in normal organoids, calcitriol inhibited early signaling by BMP4 as assessed by reduction of the level of phospho-SMAD1/5/8. Our results show that BMP and Notch signaling play key roles in human colon stem cell differentiation to the enterocytic and goblet cell lineages and that calcitriol modulates these processes favoring stemness features.

BPTF cooperates with MYCN and MYC to link neuroblastoma cell cycle control to epigenetic cellular states.

The nucleosome remodeling factor BPTF is required for the deployment of the MYC-driven transcriptional program. Deletion of one Bptf allele delays tumor progression in mouse models of pancreatic cancer and lymphoma. In neuroblastoma, MYCN cooperates with the transcriptional core regulatory circuitry (CRC). High BPTF levels are associated with high-risk features and decreased survival. BPTF depletion results in a dramatic decrease of cell proliferation. Bulk RNA-seq, single-cell sequencing, and tissue microarrays reveal a positive correlation of BPTF and CRC transcription factor expression. Immunoprecipitation/mass spectrometry shows that BPTF interacts with MYCN and the CRC proteins. Genome-wide distribution analysis of BPTF and CRC in neuroblastoma reveals a dual role for BPTF: 1) it co-localizes with MYCN/MYC at the promoter of genes involved in cell cycle and 2) it co-localizes with the CRC at super-enhancers to regulate cell identity. The critical role of BPTF across neuroblastoma subtypes supports its relevance as a therapeutic target.

A common CTRB misfolding variant associated with pancreatic cancer risk causes ER stress and inflammation in mice.

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.

Protein kinase C (PKC)-promoted endocytosis of glutamate transporter GLT-1 requires ubiquitin ligase Nedd4-2-dependent ubiquitination but not phosphorylation.

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 PKC activation. These results indicate that GLT-1 endocytosis is independent of its phosphorylation and that Nedd4-2 mediates PKC-dependent down-regulation of the transporter.

A novel dominant hyperekplexia mutation Y705C alters trafficking and biochemical properties of the presynaptic glycine transporter GlyT2.

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, [(3)H]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 Zn(2+) dependence of glycine transport that may affect the function of glycinergic neurotransmission in vivo.

Mitochondrial localization of the forkhead box class O transcription factor FOXO3a in brain.

FOXO3a is member of the Forkhead box class O transcription factors, which functions in diverse pathways to regulate cellular metabolism, differentiation, and apoptosis. FOXO3a shuttles between the cytoplasm and nucleus and may be activated in neurons by stressors, including seizures. A subset of nuclear transcription factors may localize to mitochondria, but whether FOXO3a is present within brain mitochondria is unknown. Here, we report that purified mitochondrial fractions from rat, mouse, and human hippocampus, as well as HT22 hippocampal cells, contain FOXO3a protein. Immunogold electron microscopy supported the presence of FOXO3a within brain mitochondria, and chromatin immunoprecipitation analysis suggested FOXO3a was associated with mitochondrial DNA. Over-expression of a mitochondrially targeted FOXO3a fusion protein in HT22 cells, but not primary hippocampal neurons, conferred superior protection against glutamate toxicity than FOXO3a alone. Mitochondrial FOXO3a levels were reduced in the damaged region of the mouse hippocampus after status epilepticus, while mitochondrial fractions from the hippocampus of patients with temporal lobe epilepsy displayed higher levels of FOXO3a than controls. These results support mitochondria as a site of FOXO3a localization, which may contribute to the overall physiological and pathophysiological functions of this transcription factor.

Three-dimensional, digital, and gross anatomy of the Lisfranc ligament.

BACKGROUND: There are inconsistencies in the descriptive anatomy of the Lisfranc ligament. No information is available on orientation of fibers or presence of bundles, nor are there 3-dimensional anatomic data on the ligaments or their attachments. This study assessed the 3-dimensional anatomy of the Lisfranc ligament and its attachment sites. METHODS: A total of 37 cadaver feet were dissected to expose the ligament attachments at the Lisfranc joint. The Lisfranc ligament and plantar ligament attachments were outlined separately and then removed with the attachment outlines preserved. A 3-dimensional digitizer was used to digitize bony and articular surfaces, as well as ligament attachment sites, at approximately 1 mm intervals; the positional accuracy was 0.23 mm. The surface areas of the entire bone, articular regions, and Lisfranc and plantar ligament attachment regions were determined and anatomic details were noted. RESULTS: The Lisfranc ligament had a single bundle in 73% of the specimens and 2 bundles in 27%. Both variations had a single attachment to the second metatarsal (M2; mean attachment surface area, 135 mm(2)). The single-bundle variation attached to the medial cuneiform (C1; mean attachment surface area, 140 mm(2)). The plantar ligament, C1-M2-M3, attached to the anterior plantar surface of the lateral aspect of C1 (mean attachment surface, 64 mm(2)) and had attachment sites at the bases of M2 and M3. Its fibers ran anteriorly and inferiorly, with attachments to the proximal inferomedial aspect of M2 (mean attachment surface, 63 mm(2)) and fibers extending to a smaller attachment at the plantar aspect of M3 (mean attachment surface area, 26 mm(2)). CONCLUSION: The Lisfranc ligament is variable in anatomy and can have a single- or double-bundle arrangement. Its area of attachment is larger than that of the plantar ligament. CLINICAL RELEVANCE: Anatomic descriptions of location, dimensions, and variability in the position and surface area of the ligament attachment sites and of orientation of the bundles provide information for future attempts at repair or reconstruction of the Lisfranc ligament.

Tumor and Stromal Cell Targeting with Nintedanib and Alpelisib Overcomes Intrinsic Bladder Cancer Resistance.

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.

NFIC regulates ribosomal biology and ER stress in pancreatic acinar cells and restrains PDAC initiation.

Pancreatic acinar cells rely on PTF1 and other transcription factors to deploy their transcriptional program. We identify NFIC as a NR5A2 interactor and regulator of acinar differentiation. NFIC binding sites are enriched in NR5A2 ChIP-Sequencing peaks. Nfic knockout mice have a smaller, histologically normal, pancreas with reduced acinar gene expression. NFIC binds and regulates the promoters of acinar genes and those involved in RNA/protein metabolism, and Nfic knockout pancreata show defective ribosomal RNA maturation. NFIC dampens the endoplasmic reticulum stress program through binding to gene promoters and is required for resolution of Tunicamycin-mediated stress. NFIC is down-regulated during caerulein pancreatitis and is required for recovery after damage. Normal human pancreata with low levels of NFIC transcripts display reduced expression of genes down-regulated in Nfic knockout mice. NFIC expression is down-regulated in mouse and human pancreatic ductal adenocarcinoma. Consistently, Nfic knockout mice develop a higher number of mutant Kras-driven pre-neoplastic lesions.

Cell surface turnover of the glutamate transporter GLT-1 is mediated by ubiquitination/deubiquitination.

The main glutamate transporter in the brain, GLT-1, mediates glutamatergic neurotransmission in both physiological and pathological conditions. GLT-1 activity is controlled by both constitutive and regulated trafficking, and although recent evidence indicates that the turnover of this protein in the plasma membrane is accelerated by protein kinase C via an ubiquitin-dependent process, the mechanisms driving the constitutive trafficking of GLT-1 remain unexplored. Here, we used a heterologous system and primary astrocytes to investigate the turnover of GLT-1 and the role of ubiquitin attachment in this process. We show that GLT-1 is endocytosed constitutively in a clathrin-dependent manner, recycling the transporter into endosomes containing EEA1 and Rab4, a marker of rapidly recycling endosomes, and not Rab11 or Rab7, markers of the slow recycling and late endosomal compartments, respectively. We also show that this process is dependent on ubiquitination, because the inhibitor of the ubiquitin-activating enzyme E1, 4[4-(5-nitro-furan-2-ylmethylene)-3,5-dioxo-pyrazolidin-1-yl]-benzoic acid ethyl ester, promotes the retention of GLT-1 at the plasma membrane. Moreover, site-directed mutagenesis demonstrated the involvement of lysines 517 and 526 of GLT-1 in the constitutive internalization of the transporter. The translocation of GLT-1 from the recycling endosomes to the plasma membrane was blocked by LDN-57444, a specific inhibitor to the deubiquitinating enzyme (DUB) ubiquitin C-terminal hydrolase-L1, but not by an inhibitor of the related DUB ubiquitin C-terminal hydrolase-L3, supporting the existence of specific ubiquitination/deubiquitination cycles that ensure the correct concentrations of GLT-1 at the cell surface.

Deciphering the roadmap of in vivo reprogramming toward pluripotency.

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.

Phase I, multicenter, open-label study of intravenous VCN-01 oncolytic adenovirus with or without nab-paclitaxel plus gemcitabine in patients with advanced solid tumors.

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 1×1013 viral particles (vp)/patient (Part I), and 3.3×1012 vp/patient (Part II). Fourteen patients were included in Part III: there were no DLTs and the RP2D was 1×1013 vp/patient. Observed DLTs were grade 4 aspartate aminotransferase increase in one patient (Part I, 1×1013 vp), grade 4 febrile neutropenia in one patient and grade 5 thrombocytopenia plus enterocolitis in another patient (Part II, 1×1013 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.

Time to a Negative SARS-CoV-2 PCR Predicts Delayed Return to Work After Medical Leave in COVID-19 Infected Health Care Workers.

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.

Secondary resistance to anti-EGFR therapy by transcriptional reprogramming in patient-derived colorectal cancer models.

BACKGROUND: The development of secondary resistance (SR) in metastatic colorectal cancer (mCRC) treated with anti-epidermal growth factor receptor (anti-EGFR) antibodies is not fully understood at the molecular level. Here we tested in vivo selection of anti-EGFR SR tumors in CRC patient-derived xenograft (PDX) models as a strategy for a molecular dissection of SR mechanisms. METHODS: We analyzed 21 KRAS, NRAS, BRAF, and PI3K wildtype CRC patient-derived xenograft (PDX) models for their anti-EGFR sensitivity. Furthermore, 31 anti-EGFR SR tumors were generated via chronic in vivo treatment with cetuximab. A multi-omics approach was employed to address molecular primary and secondary resistance mechanisms. Gene set enrichment analyses were used to uncover SR pathways. Targeted therapy of SR PDX models was applied to validate selected SR pathways. RESULTS: In vivo anti-EGFR SR could be established with high efficiency. Chronic anti-EGFR treatment of CRC PDX tumors induced parallel evolution of multiple resistant lesions with independent molecular SR mechanisms. Mutations in driver genes explained SR development in a subgroup of CRC PDX models, only. Transcriptional reprogramming inducing anti-EGFR SR was discovered as a common mechanism in CRC PDX models frequently leading to RAS signaling pathway activation. We identified cAMP and STAT3 signaling activation, as well as paracrine and autocrine signaling via growth factors as novel anti-EGFR secondary resistance mechanisms. Secondary resistant xenograft tumors could successfully be treated by addressing identified transcriptional changes by tailored targeted therapies. CONCLUSIONS: Our study demonstrates that SR PDX tumors provide a unique platform to study molecular SR mechanisms and allow testing of multiple treatments for efficient targeting of SR mechanisms, not possible in the patient. Importantly, it suggests that the development of anti-EGFR tolerant cells via transcriptional reprogramming as a cause of anti-EGFR SR in CRC is likely more prevalent than previously anticipated. It emphasizes the need for analyses of SR tumor tissues at a multi-omics level for a comprehensive molecular understanding of anti-EGFR SR in CRC.

Kinematic comparison of the use of walking sticks versus a rolling walker during gait in adult degenerative scoliosis patients.

STUDY DESIGN: A repeated-measurement, single-center, prospective study. OBJECTIVE: To compare the spatiotemporal and kinematic data using gait analysis in adult degenerative scoliosis (ADS) patients using walking sticks (WS) versus rolling walkers (RW). ADS patients undergo compensatory changes that can result in an altered gait pattern. RW are frequently prescribed, but result in a forward flexed kyphotic posture during ambulation. Gait using WS allows for more upright alignment in ADS patients. METHODS: Fifty-three ADS patients with symptomatic degenerative scoliosis performed over-ground walking at self-selected speed with WS and with a RW. Trunk and lower extremity angles along with spatiotemporal parameters were measured and compared. RESULTS: When using WS, patients exhibited less flexion at the head (WS: - 4.8° vs. RW: 11.0°, p = 0.001), and lumbar spine (WS: - 0.9° vs. RW: 4.2°, p = 0.001); while there was significantly more extension, of the cervical spine (WS: - 1.6° vs. RW: - 7.4°, p = 0.002) when using the RW. At the initial contact phase of gait, patients using WS showed decreased flexion at the ankle (WS 0.7° vs. RW: 3.8°, p = 0.018), knee (WS: 0.3° vs. RW: 4.8°, p = 0.001), hip (WS: 22.6° vs. RW: 27.3°, p = 0.001), and pelvis (WS: 10.2° vs. RW: 14.8°, p = 0.001). In contrast, the use of WS resulted in slower ambulation (WS: 0.6 m/s vs. RW: 0.7 m/s, p = 0.001). CONCLUSIONS: In ADS patients who have not undergone surgical correction, the use of WS resulted in a more upright posture, which may be more beneficial to the compensatory changes that lead to gait disturbance in ADS patients. Ambulation using WS resulted in slower gait versus a RW, due to the momentum induced by the forward flexed posture when using a RW. We recommend the use of WS for patients with ADS as it improves gait kinematics and may be a safer option.