Human organoid models to study SARS-CoV-2 infection.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the deadliest pandemics in history. SARS-CoV-2 not only infects the respiratory tract, but also causes damage to many organs. Organoids, which can self-renew and recapitulate the various physiology of different organs, serve as powerful platforms to model COVID-19. In this Perspective, we overview the current effort to apply both human pluripotent stem cell-derived organoids and adult organoids to study SARS-CoV-2 tropism, host response and immune cell-mediated host damage, and perform drug discovery and vaccine development. We summarize the technologies used in organoid-based COVID-19 research, discuss the remaining challenges and provide future perspectives in the application of organoid models to study SARS-CoV-2 and future emerging viruses.

SARS-CoV-2 Infection Induces Ferroptosis of Sinoatrial Node Pacemaker Cells.

BACKGROUND: Increasing evidence suggests that cardiac arrhythmias are frequent clinical features of coronavirus disease 2019 (COVID-19). Sinus node damage may lead to bradycardia. However, it is challenging to explore human sinoatrial node (SAN) pathophysiology due to difficulty in isolating and culturing human SAN cells. Embryonic stem cells (ESCs) can be a source to derive human SAN-like pacemaker cells for disease modeling. METHODS: We used both a hamster model and human ESC (hESC)-derived SAN-like pacemaker cells to explore the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on the pacemaker cells of the heart. In the hamster model, quantitative real-time polymerase chain reaction and immunostaining were used to detect viral RNA and protein, respectively. We then created a dual knock-in SHOX2:GFP;MYH6:mCherry hESC reporter line to establish a highly efficient strategy to derive functional human SAN-like pacemaker cells, which was further characterized by single-cell RNA sequencing. Following exposure to SARS-CoV-2, quantitative real-time polymerase chain reaction, immunostaining, and RNA sequencing were used to confirm infection and determine the host response of hESC-SAN-like pacemaker cells. Finally, a high content chemical screen was performed to identify drugs that can inhibit SARS-CoV-2 infection, and block SARS-CoV-2-induced ferroptosis. RESULTS: Viral RNA and spike protein were detected in SAN cells in the hearts of infected hamsters. We established an efficient strategy to derive from hESCs functional human SAN-like pacemaker cells, which express pacemaker markers and display SAN-like action potentials. Furthermore, SARS-CoV-2 infection causes dysfunction of human SAN-like pacemaker cells and induces ferroptosis. Two drug candidates, deferoxamine and imatinib, were identified from the high content screen, able to block SARS-CoV-2 infection and infection-associated ferroptosis. CONCLUSIONS: Using a hamster model, we showed that primary pacemaker cells in the heart can be infected by SARS-CoV-2. Infection of hESC-derived functional SAN-like pacemaker cells demonstrates ferroptosis as a potential mechanism for causing cardiac arrhythmias in patients with COVID-19. Finally, we identified candidate drugs that can protect the SAN cells from SARS-CoV-2 infection.

Transanal irrigation in functional bowel disorders and LARS: short-term results from an Italian national study.

PURPOSE: To evaluate the potential benefits associated with the short-term (6 months) treatment with transanal irrigation (TAI) in patients suffering from functional constipation (FC), functional fecal incontinence (FI), and low anterior resection syndrome (LARS). METHODS: A multicenter observational study (12 centers; 369 patients) was conducted to assess the following primary and secondary objectives: to evaluate the level of satisfaction regarding bowel control and quality of life (QoL); to evaluate bowel symptoms severity and dropout frequency and reason. To this aim, validated questionnaires were provided to the patients at baseline (T0) and after 6 months of TAI treatment (T6) performed with the medical device Peristeen® Plus (Coloplast A/S, Denmark). Statistical analyses were conducted to compare the outcomes obtained at T0 and T6. RESULTS: A 6-month treatment with TAI enabled a statistically significant (p < 0.05) improvement of QoL scores, satisfaction scores regarding bowel control, and severity indexes of disorder-related symptoms in patients suffering from FC, FI, and LARS. Globally, 8.0% of patients discontinued the treatment after 6 months as a result of occurrence of symptoms (2.4%) or other justifications (3.8%) such as personal reasons. None of the dropouts were due to treatment inefficacy. CONCLUSION: Results of the present study suggest that short-term TAI treatment is beneficial for patients suffering from functional bowel disorders and LARS. Future analysis of prospective data will focus on the clinical outcomes associated with the long-term use (up to 24 months) of TAI when dealing with these types of medical conditions.

Evaluation of the Sensitivity of Metabolic Profiling by Rapid Evaporative Ionization Mass Spectrometry: Toward More Radical Oral Cavity Cancer Resections.

Radical resection for patients with oral cavity cancer remains challenging. Rapid evaporative ionization mass spectrometry (REIMS) of electrosurgical vapors has been reported for real-time classification of normal and tumor tissues for numerous surgical applications. However, the infiltrative pattern of invasion of oral squamous cell carcinomas (OSCC) challenges the ability of REIMS to detect low amounts of tumor cells. We evaluate REIMS sensitivity to determine the minimal amount of detected tumors cells during oral cavity cancer surgery. A total of 11 OSCC patients were included in this study. The tissue classification based on 185 REIMS ex vivo metabolic profiles from five patients was compared to histopathology classification using multivariate analysis and leave-one-patient-out cross-validation. Vapors were analyzed in vivo by REIMS during four glossectomies. Complementary desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) was employed to map tissue heterogeneity on six oral cavity sections to support REIMS findings. REIMS sensitivity was assessed with a new cell-based assay consisting of mixtures of cell lines (tumor, myoblasts, keratinocytes). Our results depict REIMS classified tumor and soft tissues with 96.8% accuracy. In vivo REIMS generated intense mass spectrometric signals. REIMS detected 10% of tumor cells mixed with 90% myoblasts with 83% sensitivity and 82% specificity. DESI-MSI underlined distinct metabolic profiles of nerve features and a metabolic shift phosphatidylethanolamine PE(O-16:1/18:2))/cholesterol sulfate common to both mucosal maturation and OSCC differentiation. In conclusion, the assessment of tissue heterogeneity with DESI-MSI and REIMS sensitivity with cell mixtures characterized sensitive metabolic profiles toward in vivo tissue recognition during oral cavity cancer surgeries.

Introductory patient communication training for medical physics graduate students: Pilot experience.

Despite medical physics becoming a more patient-facing part of the radiation oncology team, medical physics graduate students have no training in patient communication. An introductory patient communication training for medical physics graduate students is presented here. This training exposes participants to foundational concepts and effective communication skills through a lecture and it allows them to apply these concepts through realistic simulated patient interactions. The training was conducted virtually, and eight students participated. The impact of the training was evaluated based on changes in both confidence and competence of the participants' patient communication skills. Participants were asked to fill out a survey to assess their confidence on communicating with patients before and after the training. They also underwent a simulated patient interaction pre- and postlecture. Their performance during these was evaluated by both the simulated patient actors and the participants themselves using a rubric. Each data set was paired and analyzed for significance using a Wilcoxon rank-sum test with an alpha of 0.05. Participants reported significantly higher confidence in their feeling of preparedness to interact with patients (mean = 2.38 vs. 3.88, p = 0.008), comfort interacting independently (mean = 2.00 vs. 4.00, p = 0.002), comfort showing patients they are actively listening (mean = 3.50 vs. 4.50, p = 0.005), and confidence handling challenging patient interactions (mean = 1.88 vs. 3.38, p = 0.01), after the training. Their encounter scores, as evaluated by the simulated patient actors, significantly increased (mean = 77% vs. 91%, p = 0.022). Self-evaluation scores increased, but not significantly (mean = 62% vs. 68%, p = 0.184). The difference between the simulated patient and self-evaluation scores for the postinstruction encounter was statistically significant (p = 0.0014). This patient communication training for medical physics graduate students is effective at increasing both the confidence and the competence of the participants in the subject. We propose that similar trainings be incorporated into medical physics graduate training programs prior to students entering into residency.

miR-126 regulates glycogen trophoblast proliferation and DNA methylation in the murine placenta.

A functional placenta develops through a delicate interplay of its vascular and trophoblast compartments. We have identified a previously unknown expression domain for the endothelial-specific microRNA miR-126 in trophoblasts of murine and human placentas. Here, we determine the role of miR-126 in placental development using a mouse model with a targeted deletion of miR-126. In addition to vascular defects observed only in the embryo, loss of miR-126 function in the placenta leads to junctional zone hyperplasia at E15.5 at the expense of the labyrinth, reduced placental volume for nutrient exchange and intra-uterine growth restriction of the embryos. Junctional zone hyperplasia results from increased numbers of proliferating glycogen trophoblast (GlyT) progenitors at E13.5 that give rise to an expanded glycogen trophoblast population at E15.5. Transcriptomic profile of miR-126-/- placentas revealed dysregulation of a large number of GlyT (Prl6a1, Prl7c1, Pcdh12) and trophoblast-specific genes (Tpbpa, Tpbpb, Prld1) and genes with known roles in placental development. We show that miR-126-/- placentas, but not miR-126-/- embryos, display aberrant expression of imprinted genes with important roles in glycogen trophoblasts and junctional zone development, including Igf2, H19, Cdkn1c and Phlda2, during mid-gestation. We also show that miR126-/- placentas display global hypermethylation, including at several imprint control centers. Our findings uncover a novel role for miR-126 in regulating extra-embryonic energy stores, expression of imprinted genes and DNA methylation in the placenta.

Altered feto-placental vascularization, feto-placental malperfusion and fetal growth restriction in mice with Egfl7 loss of function.

EGFL7 is a secreted angiogenic factor produced by embryonic endothelial cells. To understand its role in placental development, we established a novel Egfl7 knockout mouse. The mutant mice have gross defects in chorioallantoic branching morphogenesis and placental vascular patterning. Microangiography and 3D imaging revealed patchy perfusion of Egfl7-/- placentas marked by impeded blood conductance through sites of narrowed vessels. Consistent with poor feto-placental perfusion, Egfl7 knockout resulted in reduced placental weight and fetal growth restriction. The placentas also showed abnormal fetal vessel patterning and over 50% reduction in fetal blood space. In vitro, placental endothelial cells were deficient in migration, cord formation and sprouting. Expression of genes involved in branching morphogenesis, Gcm1, Syna and Synb, and in patterning of the extracellular matrix, Mmrn1, were temporally dysregulated in the placentas. Egfl7 knockout did not affect expression of the microRNA embedded within intron 7. Collectively, these data reveal that Egfl7 is crucial for placental vascularization and embryonic growth, and may provide insight into etiological factors underlying placental pathologies associated with intrauterine growth restriction, which is a significant cause of infant morbidity and mortality.

Detection of Bone Marrow Edema in the Head and Neck With Dual-Energy CT: Ready for Clinical Use?

OBJECTIVE. The aim of this study is to evaluate the ability of dual-energy CT (DECT) to identify bone marrow edema (BME) in the head and neck region in comparison with MRI as the standard of reference. MATERIALS AND METHODS. A total of 33 patients who underwent imaging between February 2016 and February 2018 were included in this retrospective study. All patients underwent both DECT and MRI for head and neck abnormalities. Two radiologists independently visually assessed virtual noncalcium (VNCa) reconstructions with color-coded maps for the presence of BME. STIR or T2-weighted MRI reconstructions with fat suppression were used as the standard of reference for BME. Subjective quality assessment and severity of metal artifacts were scored on both imaging modalities. RESULTS. BME was detected in 18 patients on DECT compared with 20 patients on MRI. Most BME seen on DECT was located in the mandible. VNCa DECT images had a sensitivity, specificity, positive predictive value, and negative predictive value for BME of 85%, 92%, 94%, and 80% respectively, using MRI as the reference. The quality of the images was rated as excellent to moderate in 94% of the patients for VNCa DECT compared with 82% of the patients for MRI, but this difference was not statistically significant. Significantly more metal artifacts were scored on the mixed DECT images than on the MR images, but these artifacts did not interfere with diagnosis. CONCLUSION. BME detection in the head and neck region seems possible with VNCa DECT images and has the potential to provide an alternative for MRI in clinical practice.

Evaluation and management of perianal abscess and anal fistula: SICCR position statement.

Perianal sepsis is a common condition ranging from acute abscess to chronic anal fistula. In most cases, the source is considered to be a non-specific cryptoglandular infection starting from the intersphincteric space. Surgery is the main treatment and several procedures have been developed, but the risks of recurrence and of impairment of continence still seem to be an unresolved issue. This statement reviews the pertinent literature and provides evidence-based recommendations to improve individualized management of patients.

Characterization of an Inducible Alcoholic Liver Fibrosis Model for Hepatocellular Carcinoma Investigation in a Transgenic Porcine Tumorigenic Platform.

PURPOSE: This study used the Oncopig Cancer Model (OCM) to develop alcohol-induced fibrosis in a porcine model capable of developing hepatocellular carcinoma. MATERIALS AND METHODS: Liver injury was induced in 8-week-old Oncopigs (n = 10) via hepatic transarterial infusion of 0.75 mL/kg ethanol-ethiodized oil (1:3 v/v). Feasibility was assessed in an initial Oncopig cohort (n = 5) by histologic analysis at 8 weeks after induction, and METAVIR results were compared to age- and sex-matched healthy controls (n = 5). Liver injury was then induced in a second OCM cohort (n = 5) for a time-course study, with post-induction disease surveillance via biweekly physical exam, lab analysis, and liver biopsies until 20 weeks after induction. RESULTS: In Cohort 1, 8-week post-induction liver histologic analysis revealed median METAVIR F3 (range, F3-F4) fibrosis, A2 (range, A2-A3) inflammation, and 15.3% (range, 5.0%-22.9%) fibrosis. METAVIR and inflammation scores were generally elevated compared to healthy controls (F0-F1, P = 0.0013; A0-A1, P = .0013; median percent fibrosis 8.7%, range, 5.8%-12.1%, P = .064). In Cohort 2, histologic analysis revealed peak fibrosis severity of median METAVIR F3 (range, F2-F3). However, lack of persistent alcohol exposure resulted in liver recovery, with median METAVIR F2 (range, F1-F2) fibrosis at 20 weeks after induction. No behavioral or biochemical abnormalities were observed to indicate liver decompensation. CONCLUSIONS: This study successfully validated a protocol to develop METAVIR F3-F4 fibrosis within 8 weeks in the OCM, supporting its potential to serve as a model for hepatocellular carcinoma in a fibrotic liver background. Further investigation is required to determine if repeated alcohol liver injury is required to develop an irreversible METAVIR grade F4 porcine cirrhosis model.

Anal Fistula Laser Closure: the length of fistula is the Achilles' heel.

BACKGROUND: Laser closure is a novel sphincter-saving technique for the treatment of anal fistula. The aim of this study was to report middle term results of laser treatment without closure of the internal orifice and to identify prognostic factors to improve selection criteria and maximize healing. METHODS: A retrospective observational study was conducted on patients treated with laser for transphinteric anal fistula. A diode laser emitting laser energy of 12W at a wavelength of 1470 nm was used. The relationship between fistula healing and age, sex, previous fistula surgery, location of fistula, and length of fistula tract was investigated. A successful outcome was defined by the complete healing of the surgical wound and external opening for at least 6 months. RESULTS: Thirty patients (16 males, median age 52 years, range 26-72 years) underwent laser fistula closure between January 2015 and December 2016. Cure was achieved in 10 patients (33.3%). The mean follow-up was 11.30 months (range 6-24 months). Patients with persistent or recurrent fistula were offered repeat surgery. Eventually 4 underwent laser treatment once more. Two patients were cured leading to an overall healing rate of 40% (12 out of 30). Only 4 minor complications occurred (13.3%). No worsening of anal continence was registered. Only fistula length had a statistically significant correlation with successful treatment. Fistula tracts shorter than 30 mm were associated with a primary healing rate of 58.3% while tracts longer than 30 mm were cured in only 16.6% of cases (p < 0.02). CONCLUSIONS: Laser closure is a safe and effective treatment for transphinteric anal fistula. The fistula length is the only significant prognostic factor when closing anal fistulas exclusively with laser: shorter fistulas have a better outcome.

Validation of the TAPS-1: A Four-Item Screening Tool to Identify Unhealthy Substance Use in Primary Care.

BACKGROUND: The Tobacco, Alcohol, Prescription Medication, and Other Substance use (TAPS) tool is a combined two-part screening and brief assessment developed for adult primary care patients. The tool's first-stage screening component (TAPS-1) consists of four items asking about past 12-month use for four substance categories, with response options of never, less than monthly, monthly, weekly, and daily or almost daily. OBJECTIVE: To validate the TAPS-1 in primary care patients. DESIGN: Participants completed the TAPS tool in self- and interviewer-administered formats, in random order. In this secondary analysis, the TAPS-1 was evaluated against DSM-5 substance use disorder (SUD) criteria to determine optimal cut-points for identifying unhealthy substance use at three severity levels (problem use, mild SUD, and moderate-to-severe SUD). PARTICIPANTS: Two thousand adult patients at five primary care sites. MAIN MEASURES: DSM-5 SUD criteria were determined via the modified Composite International Diagnostic Interview. Oral fluid was used as a biomarker of recent drug use. KEY RESULTS: Optimal frequency-of-use cut-points on the self-administered TAPS-1 for identifying SUDs were ≥ monthly use for tobacco and alcohol (sensitivity = 0.92 and 0.71, specificity = 0.80 and 0.85, AUC = 0.86 and 0.78, respectively) and any reported use for illicit drugs and prescription medication misuse (sensitivity = 0.93 and 0.89, specificity = 0.85 and 0.91, AUC = 0.89 and 0.90, respectively). The performance of the interviewer-administered format was similar. When administered first, the self-administered format yielded higher disclosure rates for past 12-month alcohol use, illicit drug use, and prescription medication misuse. Frequency of use alone did not provide sufficient information to discriminate between gradations of substance use problem severity. Among those who denied drug use on the TAPS-1, less than 4% had a drug-positive biomarker. CONCLUSIONS: The TAPS-1 can identify unhealthy substance use in primary care patients with a high level of accuracy, and may have utility in primary care for rapid triage.

Performance of the Tobacco, Alcohol, Prescription Medication, and Other Substance Use (TAPS) Tool for Substance Use Screening in Primary Care Patients.

BACKGROUND: Substance use, a leading cause of illness and death, is underidentified in medical practice. OBJECTIVE: The Tobacco, Alcohol, Prescription medication, and other Substance use (TAPS) tool was developed to address the need for a brief screening and assessment instrument that includes all commonly used substances and fits into clinical workflows. The goal of this study was to assess the performance of the TAPS tool in primary care patients. DESIGN: Multisite study, conducted within the National Drug Abuse Treatment Clinical Trials Network, comparing the TAPS tool with a reference standard measure. (ClinicalTrials.gov: NCT02110693). SETTING: 5 adult primary care clinics. PARTICIPANTS: 2000 adult patients consecutively recruited from clinic waiting areas. MEASUREMENTS: Interviewer- and self-administered versions of the TAPS tool were compared with a reference standard, the modified World Mental Health Composite International Diagnostic Interview (CIDI), which measures problem use and substance use disorder (SUD). RESULTS: Interviewer- and self-administered versions of the TAPS tool had similar diagnostic characteristics. For identifying problem use (at a cutoff of 1+), the TAPS tool had a sensitivity of 0.93 (95% CI, 0.90 to 0.95) and specificity of 0.87 (CI, 0.85 to 0.89) for tobacco and a sensitivity of 0.74 (CI, 0.70 to 0.78) and specificity of 0.79 (CI, 0.76 to 0.81) for alcohol. For problem use of illicit and prescription drugs, sensitivity ranged from 0.82 (CI, 0.76 to 0.87) for marijuana to 0.63 (CI, 0.47 to 0.78) for sedatives; specificity was 0.93 or higher. For identifying any SUD (at a cutoff of 2+), sensitivity was lower. LIMITATIONS: The low prevalence of some drug classes led to poor precision in some estimates. Research assistants were not blinded to participants' TAPS tool responses when they administered the CIDI. CONCLUSION: In a diverse population of adult primary care patients, the TAPS tool detected clinically relevant problem substance use. Although it also may detect tobacco, alcohol, and marijuana use disorders, further refinement is needed before it can be recommended broadly for SUD screening. PRIMARY FUNDING SOURCE: National Institute on Drug Abuse.

Evaluation and management of perianal abscess and anal fistula: a consensus statement developed by the Italian Society of Colorectal Surgery (SICCR).

Perianal sepsis is a common condition ranging from acute abscess to chronic fistula formation. In most cases, the source is considered to be a non-specific cryptoglandular infection starting from the intersphincteric space. The key to successful treatment is the eradication of the primary track. As surgery may lead to a disturbance of continence, several sphincter-preserving techniques have been developed. This consensus statement examines the pertinent literature and provides evidence-based recommendations to improve individualized management of patients.

Epidermal growth factor-like domain 7 is a marker of the endothelial lineage and active angiogenesis.

Epidermal growth factor-like domain 7 (Egfl7) expression in the developing embryo is largely restricted to sites of mesodermal progenitors of angioblasts/hemangioblasts and the vascular endothelium. We hypothesize that Egfl7 marks the endothelial lineage during embryonic development, and can be used to define the emergence of endothelial progenitor cells, as well as to visualize newly-forming vasculature in the embryo and during the processes of physiologic and pathologic angiogenesis in the adult. We have generated a transgenic mouse strain that expresses enhanced green fluorescent protein (eGFP) under the control of a minimal Egfl7 regulatory sequence (Egfl7:eGFP). Expression of the transgene recapitulated that of endogenous Egfl7 at sites of vasculogenesis and angiogenesis in the allantois, yolk sac, and in the embryo proper. The transgene was not expressed in the quiescent endothelium of most adult organs. However, the uterus and ovary, which undergo vascular growth and remodeling throughout the estrus cycle, expressed high levels of Egfl7:eGFP. Importantly, expression of the Egfl7:eGFP transgene was induced in adult neovasculature. We also found that increased Egfl7 expression contributed to pathologic revascularization in the mouse retina. To our knowledge, this is the first mouse model that enables monitoring of endothelial cells at sites of active vasculogenesis and angiogenesis. This model also facilitated the isolation and characterization of EGFL7(+) endothelial cell populations by fluorescence activated cell sorting (FACS). Together, our results demonstrate that the Egfl7:eGFP reporter mouse is a valuable tool that can be used to elucidate the mechanisms by which blood vessels form during development and under pathologic circumstances.

Atacama Clear for Complex 3D Imaging of Organs.

3D reconstructive imaging is a powerful strategy to interrogate the global architecture of tissues. We developed Atacama Clear (ATC), a novel method that increases 3D imaging signal-to-noise ratios (SNRs) while simultaneously increasing the capacity of tissue to be cleared. ATC potentiated the clearing capacity of all tested chemical reagents currently used for optical clearing by an average of 68%, and more than doubled SNRs. This increased imaging efficacy enabled multiplex interrogation of tough fibrous tissue and specimens that naturally exhibit high levels of background noise, including the heart, kidney, and human biopsies. Indeed, ATC facilitated visualization of previously undocumented adjacent nephron segments that exhibit notoriously high autofluorescence, elements of the cardiac conduction system, and the distinct human glomerular tissue layers, at single cell resolution. Moreover, ATC was validated to be compatible with fluorescent reporter proteins in murine, zebrafish, and 3D stem cell model systems. These data establish ATC for 3D imaging studies of challenging tissue types.

Pediatric Residents Knowledge of Penicillin Allergy.

Penicillin allergy knowledge has not been evaluated specifically in the pediatric resident population. An anonymous electronic survey was distributed to all the pediatric residents in a single residency program to ascertain knowledge of penicillin allergies and allergy history taking skills. Responses among each resident class were compared using the Fisher exact test, 2-tailed. A total of 46 (52%) of 88 pediatric residents completed the survey. Only 63% reported to have had prior penicillin allergy education. All residents incorrectly identified low-risk symptoms as high-risk symptoms. The knowledge of penicillin allergy was poor across all training levels with no improvement over the duration of training. There is large support in the literature for de-labeling penicillin allergy in patients. Pediatric residents evaluate patients in childhood when most of the allergy labeling occurs. We need to consider strategies for incorporating penicillin allergy education in pediatric residency training.

Epigenetic disruptions in the offspring hypothalamus in response to maternal infection.

DNA methylation is an epigenetic modification that can alter gene expression, and the incidence can vary across developmental stages, inflammatory conditions, and sexes. The effects of viral maternal viral infection and sex on the DNA methylation patterns were studied in the hypothalamus of a pig model of immune activation during development. DNA methylation at single-base resolution in regions of high CpG density was measured on 24 individual hypothalamus samples using reduced representation bisulfite sequencing. Differential over- and under-methylated sites were identified and annotated to proximal genes and corresponding biological processes. A total of 120 sites were differentially methylated (FDR-adjusted p-value < 0.05) between maternal infection or sex groups. Among the 66 sites differentially methylated between groups exposed to inflammatory signals and control, most sites were over-methylated in the challenged group and included sites in the promoter regions of genes SIRT3 and NRBP1. Among the 54 differentially methylated sites between females and males, most sites were over-methylated in females and included sites in the promoter region of genes TNC and EIF4G1. The analysis of the genes proximal to the differentially methylated sites suggested that biological processes potentially impacted include immune response, neuron migration and ensheathment, peptide signaling, adaptive thermogenesis, and tissue development. These results suggest that translational studies should consider that the prolonged effect of maternal infection during gestation may be enacted through epigenetic regulatory mechanisms that may differ between sexes.

A MTA2-SATB2 chromatin complex restrains colonic plasticity toward small intestine by retaining HNF4A at colonic chromatin.

Plasticity among cell lineages is a fundamental, but poorly understood, property of regenerative tissues. In the gut tube, the small intestine absorbs nutrients, whereas the colon absorbs electrolytes. In a striking display of inherent plasticity, adult colonic mucosa lacking the chromatin factor SATB2 is converted to small intestine. Using proteomics and CRISPR-Cas9 screening, we identify MTA2 as a crucial component of the molecular machinery that, together with SATB2, restrains colonic plasticity. MTA2 loss in the adult mouse colon activated lipid absorptive genes and functional lipid uptake. Mechanistically, MTA2 co-occupies DNA with HNF4A, an activating pan-intestinal transcription factor (TF), on colonic chromatin. MTA2 loss leads to HNF4A release from colonic chromatin, and accumulation on small intestinal chromatin. SATB2 similarly restrains colonic plasticity through an HNF4A-dependent mechanism. Our study provides a generalizable model of lineage plasticity in which broadly-expressed TFs are retained on tissue-specific enhancers to maintain cell identity and prevent activation of alternative lineages, and their release unleashes plasticity.