Search

Simple Summary To better prevent/combat recurrence and identify predictive/targetable markers upon diagnosis, we performed whole-exome sequencing (WES) of primary tumours and relapses of human papillomavirus positive (HPV+) tonsillar and base of tongue cancer (TSCC/BOTSCC) on patients treated with curative intent, with and without relapse. A specific deletion in the CDC27 gene was observed only in the primaries of 5/17 patients that recurred but in none of the 18 patients without recurrence. Furthermore, three specific variants and 26 mutated genes enriched in mucins were identified in at least 30% of all primaries irrespective of recurrence. To conclude, a specific CDC27 deletion could be specific for recurrent HPV+ TSCC/BOTSCC, while BCLAF1, AQP7 and other globally mutated genes could be of significance for further investigation. Abstract To identify predictive/targetable markers in human papillomavirus positive (HPV+) tonsillar and base of tongue cancer (TSCC/BOTSCC), whole-exome sequencing (WES) of tumours of patients with/without recurrence was performed. Forty primary tumours and adjacent normal tissue were separated by micro-dissection from formalin-fixed paraffin-embedded tissue from patients treated with curative intent 2000–2014 at Karolinska University Hospital. Successful sequencing was obtained in primary tumours of 18 patients without and primaries of 17 with local or distant recurrence, as well as in 10 corresponding recurrences (i.e., five local relapses and five distant metastases) from these 17 patients. One variant—a high-impact deletion in the CDC27 gene—was observed only in primaries of 5/17 patients that had a recurrence after full treatment but in none of those without recurrence. In addition, 3 variants and 26 mutated genes, including CDC27, BCLAF1 and AQP7, were present in at least 30% of all primary tumours independent of prognosis. To conclude, a CDC27 deletion was specific and found in ~30% of samples from patients with a local relapse/distant metastasis and could, therefore, potentially be a prospective marker to predict prognosis. Commonly mutated genes, such as BCLAF1, should be further studied in the context of targeted therapy.

Background Hypopharyngeal cancer (HPSCC) shows a poor clinical outcome, while HPSCC, caused by human papillomavirus (HPV), presents a better outcome. Here, HPCC, immune proteins, and tumor infiltrating CD8+ lymphocytes (CD8+ TILs) were evaluated in relation to HPV and outcome. Methods Fresh frozen tissue from four HPV-positive HPSCC, 39 HPV-negative HPSCC, and normal samples were analyzed for protein expression by the Proseek immuno-oncology immunoassay. CD8+ TIL numbers evaluated by immunohistochemistry on 144 formalin-fixed biopsies were analyzed in relation to clinical outcome. Results Proteins differing between HPV-positive and negative HPSCC included CD8A, PD-L1, Fas ligand, and chemokines. High CD8+ TIL numbers were correlated to improve clinical outcome in HPV-negative HPSCC. Conclusions High expression of immune proteins in HPV-positive HPSCC may explain the better clinical outcome. CD8+ TILs are of relevance for outcome of HPV-negative HPSCC, while tumors with high immune activity but poor patient survival suggest a role for immune therapy.

To identify predictive/targetable markers in human papillomavirus positive (HPV+) tonsillar and base of tongue cancer (TSCC/BOTSCC), whole-exome sequencing (WES) of tumours of patients with/without recurrence was performed. Forty primary tumours and adjacent normal tissue were separated by micro-dissection from formalin-fixed paraffin-embedded tissue from patients treated with curative intent 2000–2014 at Karolinska University Hospital. Successful sequencing was obtained in primary tumours of 18 patients without and primaries of 17 with local or distant recurrence, as well as in 10 corresponding recurrences (i.e., five local relapses and five distant metastases) from these 17 patients. One variant—a high-impact deletion in the CDC27 gene—was observed only in primaries of 5/17 patients that had a recurrence after full treatment but in none of those without recurrence. In addition, 3 variants and 26 mutated genes, including CDC27, BCLAF1 and AQP7, were present in at least 30% of all primary tumours independent of prognosis. To conclude, a CDC27 deletion was specific and found in ~30% of samples from patients with a local relapse/distant metastasis and could, therefore, potentially be a prospective marker to predict prognosis. Commonly mutated genes, such as BCLAF1, should be further studied in the context of targeted therapy.

Human papillomavirus (HPV) infection is one of the most common sexually transmitted diseases. To define the HPV-associated microbial community among a high vaccination coverage population, we carried out a cross-sectional study with 345 young Swedish women. The microbial composition and its association with HPV infection, including 27 HPV types, were analyzed. Microbial alpha-diversity was found significantly higher in the HPV-infected group (especially with oncogenic HPV types and multiple HPV types), compared with the HPV negative group. The vaginal microbiota among HPV-infected women was characterized by a larger number of bacterial vaginosis-associated bacteria (BVAB), Sneathia, Prevotella, and Megasphaera. In addition, the correlation analysis demonstrated that twice as many women with non-Lactobacillus-dominant vaginal microbiota were infected with oncogenic HPV types, compared with L. crispatus-dominated vaginal microbiota. The data suggest that HPV infection, especially oncogenic HPV types, is strongly associated with a non-Lactobacillus-dominant vaginal microbiota, regardless of age and vaccination status.

The structure-guided design of chloride-conducting channelrhodopsins has illuminated mechanisms underlying ion selectivity of this remarkable family of light-activated ion channels. The first generation of chloride-conducting channelrhodopsins, guided in part by development of a structure-informed electrostatic model for pore selectivity, included both the introduction of amino acids with positively charged side chains into the ion conduction pathway and the removal of residues hypothesized to support negatively charged binding sites for cations. Engineered channels indeed became chloride selective, reversing near −65 mV and enabling a new kind of optogenetic inhibition; however, these first-generation chloride-conducting channels displayed small photocurrents and were not tested for optogenetic inhibition of behavior. Here we report the validation and further development of the channelrhodopsin pore model via crystal structure-guided engineering of next-generation light-activated chloride channels (iC++) and a bistable variant (SwiChR++) with net photocurrents increased more than 15-fold under physiological conditions, reversal potential further decreased by another ∼15 mV, inhibition of spiking faithfully tracking chloride gradients and intrinsic cell properties, strong expression in vivo, and the initial microbial opsin channel-inhibitor–based control of freely moving behavior. We further show that inhibition by light-gated chloride channels is mediated mainly by shunting effects, which exert optogenetic control much more efficiently than the hyperpolarization induced by light-activated chloride pumps. The design and functional features of these next-generation chloride-conducting channelrhodopsins provide both chronic and acute timescale tools for reversible optogenetic inhibition, confirm fundamental predictions of the ion selectivity model, and further elucidate electrostatic and steric structure–function relationships of the light-gated pore.

In this study chemotherapy response in neuroblastoma (NB) was assessed for the first time in a transplantation model comprising non-malignant human embryonic microenvironment of pluripotent stem cell teratoma (PSCT) derived from diploid bona fide hESC. Two NB cell lines with known high-risk phenotypes; the multi-resistant BE(2)-C and the drug sensitive IMR-32, were transplanted to the PSCT model and the tumour growth was exposed to single or repeated treatments with doxorubicin, and thereafter evaluated for cell death, apoptosis, and proliferation. Dose dependent cytotoxic effects were observed, this way corroborating the experimental platform for this type of analysis. Notably, analysis of doxorubicin-resilient BE(2)-C growth in the PSCT model revealed an unexpected 1,5-fold increase in Ki67-index (p3-fold increase in active cell cycle (i.e. cells positive staining for PH3 together with incorporation of EdU) (p

// Cinzia Bersani 1 , Lars Sivars 1 , Linnea Haeggblom 1 , Sebastian DiLorenzo 2,3 , Michael Mints 4,5 , Andreas Ahrlund-Richter 1 , Nikolaos Tertipis 1 , Eva Munck-Wikland 6,7 , Anders Nasman 1 , Torbjorn Ramqvist 1,* and Tina Dalianis 1,* 1 Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden 2 Department of Medical Sciences, Uppsala University, Uppsala, Sweden 3 National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden 4 Department of Medicine, Karolinska Institutet, Stockholm, Sweden 5 Department of Surgical and Perioperative Sciences, Umea University, Umea, Sweden 6 Department of Clinical Science and Technology, Karolinska Institutet, Stockholm, Sweden 7 Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Karolinska University Hospital, Stockholm, Sweden * These authors have contributed equally to this work Correspondence to: Cinzia Bersani, email: // Keywords : HPV, tonsillar cancer, base of tongue cancer, cancer of unknown primary of the head and neck region, FGFR3 mutation Received : December 21, 2016 Accepted : January 24, 2017 Published : February 09, 2017 Abstract BACKGROUND: Human papillomavirus positive (HPV + ) tonsillar cancer (TSCC), base of tongue cancer (BOTSCC) and unknown primary cancer of the head and neck (HNCUP) have better outcome than corresponding HPV - cancers. To find predictive markers for response to treatment, and correlations and differences in mutated oncogenes and suppressor genes between HPV + TSCC/BOTSSCC and HPV + HNCUP and HPV - TSCC/BOTSCC targeted next-generation sequencing was performed of frequently mutated regions in 50 cancer related genes. PATIENTS AND METHODS: DNA from 348 TSCC/BOTSCC and 20 HNCUP from patients diagnosed 2000-2011, was sequenced by the Ion Proton sequencing platform using the Ion AmpliSeq Cancer Hotspot Panel v2 to identify frequently mutated regions in 50 cancer related genes. Ion Torrent Variant Caller software was used to call variants. RESULTS: 279 HPV + TSCC/BOTSCC, 46 HPV - TSCC/BOTSCC and 19 HPV + HNCUP samples qualified for further analysis. Mutations/tumor were fewer in HPV + TSCC/BOTSCC and HNCUP, compared to HPV - tumors (0.92 vs . 1.32 vs . 1.68). Differences in mutation frequency of TP53 and PIK3CA were found between HPV + TSCC/BOTSCC and HNCUP and HPV - TSCC/BOTSCC. In HPV + TSCC/BOTSCC presence of FGFR3 mutations correlated to worse prognosis. Other correlations to survival within the groups were not disclosed. CONCLUSIONS: In HPV + TSCC/BOTSCC mutation of PIK3CA was most frequently observed, while TP53 mutations dominated in HPV - TSCC/BOTSCC. In HPV + TSCC/BOTSCC and HNCUP, mutations/tumor were similar in frequency and fewer compared to that in HPV - TSCC/BOTSCC. Notably, FGFR3 mutations in HPV + TSCC/BOTSCC indicated worse prognosis.

Background and Aim: In 2010 HPV vaccination was subsidized in Sweden and in 2012 a national vaccination program against HPV16, 18, 6 and 11 was launched for girls ages 10-12 years. In parallel was a catch-up vaccination program for young women. To investigate base line HPV cervical and oral prevalence in non-vaccinated youth two studies were performed at a youth clinic in Stockholm 2008-2011. This project initiated 2013 aimed to follow HPV prevalence in youth since the previous studies, in the same population. Materials and Methods: 117 women, of which 73% were HPV catch-up vaccinated donated 93 cervical samples and 117 oral samples, and 54 unvaccinated men donated 54 oral samples and 47 urinary samples. All samples were tested for 27 HPV types with a PCR based system and the data was compared to that obtained in 2008-2011. The categorical Fishers exact test was used for statistical analysis due to HPV-positive samples being n< 5 for certain types. Results and Conclusion: HPV16 cervical prevalence was significantly lower in the HPV vaccinated women compared to unvaccinated women (7% and 27% respectively, p=0.033) in the 2013 group. For HPV18 and HPV6 there was a significantly lower prevalence in the 2013 vaccinated group compared to the 2008-2010 unvaccinated group (1.5% vs. 10% respectively, p=0.021 and 1.5% vs. 8% respectively, p=0.048). Overall oral HPV prevalence for both genders, was lower in the 2013 group compared to that of 2009-2011, (2.3% and 9.1% respectively, p=0.005). Male urinary prevalence was low (6%) and not efficient to follow changes in specific HPV types. The data indicate that HPV catch-up vaccination was gradually exhibiting an effect, with significant decrease of cervical HPV16 prevalence.

BACKGROUND: This study aimed to identify biomarkers for estimating the overall and prostate cancer (PCa)-specific survival in PCa patients at diagnosis. METHODS: To explore the importance of embryonic stem cell (ESC) gene signatures, we identified 641 ESC gene predictors (ESCGPs) using published microarray data sets. ESCGPs were selected in a stepwise manner, and were combined with reported genes. Selected genes were analyzed by multiplex quantitative polymerase chain reaction using prostate fine-needle aspiration samples taken at diagnosis from a Swedish cohort of 189 PCa patients diagnosed between 1986 and 2001. Of these patients, there was overall and PCa-specific survival data available for 97.9%, and 77.9% were primarily treated by hormone therapy only. Univariate and multivariate Cox proportional hazard ratios and Kaplan-Meier plots were used for the survival analysis, and a k-nearest neighbor (kNN) algorithm for estimating overall survival. RESULTS: An expression signature of VGLL3, IGFBP3 and F3 was shown sufficient to categorize the patients into high-, intermediate- and low-risk subtypes. The median overall survival times of the subtypes were 3.23, 4.00 and 9.85 years, respectively. The difference corresponded to hazard ratios of 5.86 (95% confidence interval (CI): 2.91-11.78, P

The Supplementary Information is available in the online version of this Publisher Correction.

Experimental teratoma induced from human pluripotent stem cells with normal karyotype can be described as a failed embryonic process and includes besides advanced organoid development also large elements of tissue with a prolonged occurrence of immature neural components. Such immature components, although benign, exhibit strong morphological resemblance with tumors of embryonic neuroectodermal origin. Here, we demonstrate that biopsy material from childhood tumors of neural embryonic origin transplanted to mature experimental teratoma can show an exclusive preference for matching tissue. Tumor specimens from five children with; Supratentorial primitive neuroectodermal tumor (sPNET); Pilocytic astrocytoma of the brainstem; Classic medulloblastoma; peripheral primitive neuroectodermal tumor (pPNET) or neuroblastoma (NB), respectively, were transplanted. Analysis of up to 120 sections of each tumor revealed an engraftment for three of the transplanted tumors: pPNET, sPNET, and NB, with a protruding growth from the latter two that were selected for detailed examination. The histology revealed a strict tropism with a non-random integration into what morphologically appeared as matched embryonic microenvironment recuperating the patient tumor histology. The findings suggest specific advantages over xenotransplantation and lead us to propose that transplantation to the human embryonic microenvironment in experimental teratoma can be a well-needed complement for preclinical in vivo studies of childhood neuroectodermal tumors.

Embryonic neural tumors are responsible for a disproportionate number of cancer deaths in children. Although dramatic improvements in survival for pediatric malignancy has been achieved in previous years advancements seem to be slowing down. For the development of new enhanced therapy and an increased understanding of the disease, pre-clinical models better capturing the neoplastic niche are essential. Tumors of early childhood present in this respect a particular challenge. Here, we explore how components of the embryonic process in stem‑cell induced mature teratoma can function as an experimental in vivo microenvironment instigating the growth of injected childhood neuroblastoma (NB) cell lines. Three human NB cell lines, IMR-32, Kelly and SK-N-BE(2), were injected into mature pluripotent stem cell‑induced teratoma (PSCT) and compared to xenografts of the same cell lines. Proliferative NB cells from all lines were readily detected in both models with a typical histology of a poorly differentiated NB tumor with a variable amount of fibrovascular stroma. Uniquely in the PSCT microenvironment, NB cells were found integrated in a non‑random fashion. Neuroblastoma cells were never observed in areas with well-differentiated somatic tissue i.e. bone, muscle, gut or areas of other easily identifiable tissue types. Instead, the three cell lines all showed initial growth exclusively occurring in the embryonic loose mesenchymal stroma, resulting in a histology recapitulating NB native presentation in vivo. Whether this reflects the 'open' nature of loose mesenchyme more easily giving space to new cells compared to other more dense tissues, the rigidity of matrix providing physical cues modulating NB characteristics, or if embryonic loose mesenchyme may supply developmental cues that attracted or promoted the integration of NB, remains to be tested. We tentatively hypothesize that mature PSCT provide an embryonic niche well suited for in vivo studies on NB.

Background: Human Papilloma Virus positive (HPV+) Oropharyngeal Squamous Cell Carcinoma (OSCC), dominated by tonsillar cancer (TSCC) and base of tongue cancer (BOTSCC) has low mutation-frequency and better survival for younger than older patients.Aim: To examine if HPV+ TSCC and BOTSCC have distinct gene-mutation profiles, for 50 often-mutated genes in cancer, in younger compared to older patients and to test and compare different variant callers to get a deeper understanding of the data.Materials and methods: DNA had previously been extracted from 299 formalin-fixed-paraffin-embedded (FFPE) tumor biopsies and 13 normal samples, and sequenced on the Ion Proton sequencer, a NGS (Next-Generation Sequencing) platform. Alignment and variant calling had been performed via the Ion Torrent Suite software v5 (ITS), and Torrent Variant Caller (TVC).UPPMAX, a High-Performance-Computational cluster (HPC) at Uppsala University was used for storing and computing of the sequenced data. Parallel-processing was used to optimize repetitive steps, saving days of computation time. The descriptive analysis, graphical data representations, and more in-depth analysis, were done in R.Initially, variant calling was performed for 13 tumor/normal paired samples using the novel MuTect2 software from the Genome Analysis Toolkit (GATK) toolset. Variant annotation and statistical analysis was performed on all the 13 paired sequenced samples, using SnpEff. Due to a poor overlap between the above MuTect2 and TVC, after adequate filtering TVC, MuTect, Strelka and VarScan2 were also utilized for comparison.Result and Conclusion: Having only 13 normal samples, normal-tumor paired variant calling to distinguish germ line and somatic variants could not be performed. To obtain an approximation of the amount of germline variation in our cohort, additional variant callers were used for the tumor normal pairs. The data obtained with the TVC caller formed the basis for further analysis of the tumor samples.Notably, comparisons of TVC with MuTect2 output revealed major discrepancies and limited overlap. However, when comparing MuTect2 with MuTect, Strelka, or VarScan 2 regarding overlaps with TVC – the overlap were still limited, but higher degrees of overlaps were disclosed between Strelka, MuTect and MuTec2, indicating that MuTect2 was a successful further development and successor of MuTect.Evidence for presence of distinct gene-mutation profiles correlating to age could not be obtained in the analyzed tumor cohort with the software tool kits applied. Statistical analysis using Wilcoxon-Mann Whitney test did not support a hypothesis of distinct age related mutations for any of the 50 genes analyzed in this tumor cohorts.The highest p-value for the Wilcoxon-Mann Whitney test was for the gene APC, at p ~ 0.054 hints at a possible connection. However, more extensive research with more samples sequenced is necessary to confirm or reject this correlation.

Nodal is a TGF-β–related embryonic morphogen that is expressed in multiple human cancers. Detection of Nodal expression in these tissues can be challenging if issues related to Nodal transcription and protein processing are not considered. Here, we discuss certain characteristics related to Nodal expression and function and how these can facilitate acquisition and interpretation of expression data, contributing to our understanding of the potential role of Nodal in human cancer. We also discuss how Nodal could be exploited clinically as a novel biomarker for cancer progression and therapeutic target. Cancer Res; 72(8); 1915–20. ©2012 AACR.

For clinically relevant studies on melanoma progression and invasiveness, in vivo experimental systems with a human cellular microenvironment would be advantageous. We have compared tumor formation from a human cutaneous malignant melanoma cell line (BL), after injection as conventional xenografts in the mouse, or when injected into a predominantly species-specific environment of human embryonic stem cell–derived teratoma induced in the mouse (the hEST model). The resulting melanoma histology was generally analogous, both systems showing delimited densely packed areas with pleomorphic cells of malignant appearance. A specificity of the integration process into the human embryonic teratoma tissues was indicated by the melanoma exclusively being found in areas compatible with condensed mesenchyme, similar to neural crest development. Here, also enhanced neovascularization was seen within the human mesenchymal tissues facing the BL melanoma growth. Furthermore, in the hEST model an additional melanoma cell phenotype occurred, located at the border of, or infiltrating into, the surrounding human loose mesenchymal fibrous stroma. This BL population had a desmoplastic spindle-like appearance, with markers indicative of dedifferentiation and migration. The appearance of this apparently more aggressive phenotype, as well as the induction of human angiogenesis, shows specific interactions with the human embryonic microenvironment in the hEST model. In conclusion, these data provide exciting options for using the hEST model in molecular in vivo studies on differentiation, invasiveness, and malignancy of human melanoma, while analyzing species-specific reactions in vivo. [Cancer Res 2009;69(9):3746–54]

SummaryConsiderable practical hurdles must be overcome prior to the broad application of stem cell therapies. We outline challenges that may vary across different models of cell therapy, including the following broad concepts: issues related to the sourcing of material, and issues related to product manufacturing, shipping, storage and tracking, and standardization.

Although the first mouse embryonic stem (ES) cell lines were derived 25 years ago using feeder-layer-based blastocyst cultures, subsequent efforts to extend the approach to other mammals, including both laboratory and domestic species, have been relatively unsuccessful. The most notable exceptions were the derivation of non-human primate ES cell lines followed shortly thereafter by their derivation of human ES cells. Despite the apparent common origin and the similar pluripotency of mouse and human embryonic stem cells, recent studies have revealed that they use different signalling pathways to maintain their pluripotent status. Mouse ES cells depend on leukaemia inhibitory factor and bone morphogenetic protein, whereas their human counterparts rely on activin (INHBA)/nodal (NODAL) and fibroblast growth factor (FGF). Here we show that pluripotent stem cells can be derived from the late epiblast layer of post-implantation mouse and rat embryos using chemically defined, activin-containing culture medium that is sufficient for long-term maintenance of human embryonic stem cells. Our results demonstrate that activin/Nodal signalling has an evolutionarily conserved role in the derivation and the maintenance of pluripotency in these novel stem cells. Epiblast stem cells provide a valuable experimental system for determining whether distinctions between mouse and human embryonic stem cells reflect species differences or diverse temporal origins.

The International Stem Cell Initiative characterized 59 human embryonic stem cell lines from 17 laboratories worldwide. Despite diverse genotypes and different techniques used for derivation and maintenance, all lines exhibited similar expression patterns for several markers of human embryonic stem cells. They expressed the glycolipid antigens SSEA3 and SSEA4, the keratan sulfate antigens TRA-1-60, TRA-1-81, GCTM2 and GCT343, and the protein antigens CD9, Thy1 (also known as CD90), tissue- nonspecific alkaline phosphatase and class 1 HLA, as well as the strongly developmentally regulated genes NANOG, POU5F1 (formerly known as OCT4), TDGF1, DNMT3B, GABRB3 and GDF3. Nevertheless, the lines were not identical: differences in expression of several lineage markers were evident, and several imprinted genes showed generally similar allele-specific expression patterns, but some gene-dependent variation was observed. Also, some female lines expressed readily detectable levels of XIST whereas others did not. No significant contamination of the lines with mycoplasma, bacteria or cytopathic viruses was detected.

Hearing impairment most often involves loss of sensory hair cells and auditory neurons. As this loss is permanent in humans, a cell therapy approach has been suggested to replace damaged cells. It is thus of interest to generate lineage restricted progenitor cells appropriate for cell based therapies. Human long-term self-renewing neuroepithelial stem (lt-NES) cell lines exhibit in vitro a developmental potency to differentiate into CNS neural lineages, and importantly lack this potency in vivo, i.e do not form teratomas. Small-molecules-driven differentiation is today an established route obtain specific cell derivatives from stem cells. In this study, we have investigated the effects of three small molecules SB431542, ISX9 and Metformin to direct differentiation of lt-NES cells into sensory neurons. Exposure of lt-NES cells to Metformin or SB431542 did not induce any marked induction of markers for sensory neurons. However, a four days exposure to the ISX9 small molecule resulted in reduced expression of NeuroD1 mRNA as well as enhanced mRNA levels of GATA3, a marker and important player in auditory neuron specification and development. Subsequent culture in the presence of the neurotrophic factors BDNF and NT3 for another seven days yielded a further increase of mRNA expression for GATA3. This regimen resulted in a frequency of up to 25-30% of cells staining positive for Brn3a/Tuj1. We conclude that an approach with ISX9 small molecule induction of lt-NES cells into auditory like neurons may thus be an attractive route for obtaining safe cell replacement therapy of sensorineural hearing loss.

Non-CG methylation is an unexplored epigenetic hallmark of pluripotent stem cells. Here we report that a reduction in non-CG methylation is associated with impaired differentiation capacity into endodermal lineages. Genome-wide analysis of 2,670 non-CG sites in a discovery cohort of 25 phenotyped human induced pluripotent stem cell (hiPSC) lines revealed unidirectional loss (Δβ=13%, P, The methylation of non-CpG residues is a poorly understood marker of pluripotent cells, gradually lost as cells differentiate. Here the authors show non-CG methylation can be used as a marker of differentiation potential.

Summary While signatures of attention have been extensively studied in sensory systems, the neural sources and computations responsible for top-down control of attention are largely unknown. Using chronic recordings in mice, we found that fast-spiking parvalbumin (FS-PV) interneurons in medial prefrontal cortex (mPFC) uniformly show increased and sustained firing during goal-driven attentional processing, correlating to the level of attention. Elevated activity of FS-PV neurons on the timescale of seconds predicted successful execution of behavior. Successful allocation of attention was characterized by strong synchronization of FS-PV neurons, increased gamma oscillations, and phase locking of pyramidal firing. Phase-locked pyramidal neurons showed gamma-phase-dependent rate modulation during successful attentional processing. Optogenetic silencing of FS-PV neurons deteriorated attentional processing, while optogenetic synchronization of FS-PV neurons at gamma frequencies had pro-cognitive effects and improved goal-directed behavior. FS-PV neurons thus act as a functional unit coordinating the activity in the local mPFC circuit during goal-driven attentional processing., Graphical Abstract, Highlights • Increased firing of mPFC PV interneurons is a signature of top-down attention • Attention is characterized by synchronization of mPFC PV neurons and elevated gamma • Local pyramidal neurons show gamma-phase-dependent rate modulation during attention • Synchronization of mPFC PV neurons at gamma frequencies has pro-cognitive effects, A combination of electrophysiology and optogenetic manipulations reveal that inhibitory parvalbumin interneurons and gamma oscillations are central to prefrontal cortex's control of attention.