Prediction Model for Severe Thrombocytopenia Induced by Gemcitabine Plus Cisplatin Combination Therapy in Patients with Urothelial Cancer.

BACKGROUND: Chemotherapy-induced thrombocytopenia is often a use-limiting adverse reaction to gemcitabine and cisplatin (GC) combination chemotherapy, reducing therapeutic intensity, and, in some cases, requiring platelet transfusion. OBJECTIVE: A retrospective cohort study was conducted on patients with urothelial cancer at the initiation of GC combination therapy and the objective was to develop a prediction model for the incidence of severe thrombocytopenia using machine learning. METHODS: We performed receiver operating characteristic analysis to determine the cut-off values of the associated factors. Multivariate analyses were conducted to identify risk factors associated with the occurrence of severe thrombocytopenia. The prediction model was constructed from an ensemble model and gradient-boosted decision trees to estimate the risk of an outcome using the risk factors associated with the occurrence of severe thrombocytopenia. RESULTS: Of 186 patients included in this study, 46 (25%) experienced severe thrombocytopenia induced by GC therapy. Multivariate analyses revealed that platelet count ≤ 21.4 (×104/µL) [odds ratio 7.19, p < 0.01], hemoglobin ≤ 12.1 (g/dL) [odds ratio 2.41, p = 0.03], lymphocyte count ≤ 1.458 (×103/µL) [odds ratio 2.47, p = 0.02], and dose of gemcitabine ≥ 775.245 (mg/m2) [odds ratio 4.00, p < 0.01] were risk factors of severe thrombocytopenia. The performance of the prediction model using these associated factors was high (area under the curve 0.76, accuracy 0.82, precision 0.68, recall 0.50, and F-measure 0.58). CONCLUSIONS: Platelet count, hemoglobin level, lymphocyte count, and gemcitabine dose contributed to the development of a novel prediction model to identify the incidence of GC-induced severe thrombocytopenia.

Human Coronavirus Infection Reorganizes Spatial Genomic Architecture in Permissive Lung Cells.

Chromatin conformation capture followed by next-generation sequencing in combination with large-scale polymer simulations (4DHiC) produces detailed information on genomic loci interactions, allowing for the interrogation of 3D spatial genomic structures. Here, Hi-C data was acquired from the infection of fetal lung fibroblast (MRC5) cells with α-coronavirus 229E (CoV229E). Experimental Hi-C contact maps were used to determine viral-induced changes in genomic architecture over a 48-hour time period following viral infection, revealing substantial alterations in contacts within chromosomes and in contacts between different chromosomes. To gain further structural insight and quantify the underlying changes, we applied the 4DHiC polymer simulation method to reconstruct the 3D genomic structures and dynamics corresponding to the Hi-C maps. The models successfully reproduced experimental Hi-C data, including the changes in contacts induced by viral infection. Our 3D spatial simulations uncovered widespread chromatin restructuring, including increased chromosome compactness and A-B compartment mixing arising from infection. Our model also suggests increased spatial accessibility to regions containing interferon-stimulated genes upon infection with CoV229E, followed by chromatin restructuring at later time points, potentially inducing the migration of chromatin into more compact regions. This is consistent with previously observed suppression of gene expression. Our spatial genomics study provides a mechanistic structural basis for changes in chromosome architecture induced by coronavirus infection in lung cells.

Imprinted X chromosome inactivation at the gamete-to-embryo transition.

In mammals, dosage compensation involves two parallel processes: (1) X inactivation, which equalizes X chromosome dosage between males and females, and (2) X hyperactivation, which upregulates the active X for X-autosome balance. The field currently favors models whereby dosage compensation initiates "de novo" during mouse development. Here, we develop "So-Smart-seq" to revisit the question and interrogate a comprehensive transcriptome including noncoding genes and repeats in mice. Intriguingly, de novo silencing pertains only to a subset of Xp genes. Evolutionarily older genes and repetitive elements demonstrate constitutive Xp silencing, adopt distinct signatures, and do not require Xist to initiate silencing. We trace Xp silencing backward in developmental time to meiotic sex chromosome inactivation in the male germ line and observe that Xm hyperactivation is timed to Xp silencing on a gene-by-gene basis. Thus, during the gamete-to-embryo transition, older Xp genes are transmitted in a "pre-inactivated" state. These findings have implications for the evolution of imprinting.

Translation of a Successful Behavioral Intervention to a Digital Therapeutic Self-Management System for Older Adults.

Feature at a Glance: Nonadherence to hypertension medications is associated with negative health outcomes, which is of particular importance for older adults because of the high prevalence of hypertension in this population. To promote medication adherence among this group, we translated a behavioral intervention that improved adherence by 36% into a digital therapeutic self-management system. Design strategies included interviewing older adults, conducting usability evaluations after each iteration, and engaging a team of experts from nursing, cognitive psychology, pharmacy, human factors in aging, and software development. We outline our design process that can guide translation of other behavioral interventions into digital therapeutic platforms.

Variable expression of MECP2, CDKL5, and FMR1 in the human brain: Implications for gene restorative therapies.

MECP2, CDKL5, and FMR1 are three X-linked neurodevelopmental genes associated with Rett, CDKL5-, and fragile-X syndrome, respectively. These syndromes are characterized by distinct constellations of severe cognitive and neurobehavioral anomalies, reflecting the broad but unique expression patterns of each of the genes in the brain. As these disorders are not thought to be neurodegenerative and may be reversible, a major goal has been to restore expression of the functional proteins in the patient's brain. Strategies have included gene therapy, gene editing, and selective Xi-reactivation methodologies. However, tissue penetration and overall delivery to various regions of the brain remain challenging for each strategy. Thus, gaining insights into how much restoration would be required and what regions/cell types in the brain must be targeted for meaningful physiological improvement would be valuable. As a step toward addressing these questions, here we perform a meta-analysis of single-cell transcriptomics data from the human brain across multiple developmental stages, in various brain regions, and in multiple donors. We observe a substantial degree of expression variability for MECP2, CDKL5, and FMR1 not only across cell types but also between donors. The wide range of expression may help define a therapeutic window, with the low end delineating a minimum level required to restore physiological function and the high end informing toxicology margin. Finally, the inter-cellular and inter-individual variability enable identification of co-varying genes and will facilitate future identification of biomarkers.

Dual p38MAPK and MEK inhibition disrupts adaptive chemoresistance in mesenchymal glioblastoma to temozolomide.

BACKGROUND: Precision treatment of glioblastoma is increasingly focused on molecular subtyping, with the mesenchymal subtype particularly resistant to temozolomide. Here, we aim to develop a targeted therapy for temozolomide resensitization in the mesenchymal subtype. METHODS: We integrated kinomic profiles and kinase inhibitor screens from patient-derived proneural and mesenchymal glioma-propagating cells public clinical datasets to identify key protein kinases implicated in temozolomide resistance. RNAseq, apoptosis assays and comet assays were used to examine the role of p38MAPK signaling and adaptive chemoresistance in mesenchymal cells. The efficacy of dual p38MAPK and MEK/ERK inhibition using ralimetinib (selective orally active p38MAPK inhibitor; phase I/II for glioblastoma) and binimetinib (approved MEK1/2 inhibitor for melanoma; phase II for high-grade glioma) in primary and recurrent mesenchymal tumors was evaluated using an intracranial patient-derived tumor xenograft model, focusing on survival analysis. RESULTS: Our transcriptomic-kinomic integrative analysis revealed p38MAPK as the prime target whose gene signature enables patient stratification based on their molecular subtypes and provides prognostic value. Repurposed p38MAPK inhibitors synergize favourably with temozolomide to promote intracellular retention of temozolomide and exacerbate DNA damage. Mesenchymal cells exhibit adaptive chemoresistance to p38MAPK inhibition through a pH-/calcium-mediated MEK/ERK pathway. Dual p38MAPK and MEK inhibition effectively maintains temozolomide sensitivity in primary and recurrent intracranial mesenchymal glioblastoma xenografts. CONCLUSION: Temozolomide resistance in mesenchymal glioblastoma is associated with p38MAPK activation. Adaptive chemoresistance in p38MAPK-resistant cells is mediated by MEK/ERK signaling. Adjuvant therapy with dual p38MAPK and MEK inhibition prolongs temozolomide sensitivity, which can be developed into a precision therapy for the mesenchymal subtype.

Remote follow-up by pharmacists for blood pressure control in patients with hypertension: a systematic review and a meta-analysis of randomized controlled trials.

Hypertension is a major cause of cardiovascular diseases. Several recent studies reported that pharmacists' remote follow-up reduced hypertension patients' blood pressure (BP). This meta-analysis aims to verify whether remote follow-up by pharmacists improves BP levels and reveal the factors that make the intervention effective. The search, conducted using PubMed/Medline, Embase, and Cochrane Library from June to July 2023, targeted articles published between October 1982 and June 2023, using terms including "pharmacist", "hypertension", and "randomized controlled trial (RCT)". The inclusion criteria were: (a) RCTs involving hypertension patients with or without comorbidities, (b) pharmacists using remote communication tools to conduct follow-up encounter during the intervention period, (c) reporting systolic blood pressure (SBP) at baseline and during intervention. SBP was the primary outcome for the meta-analysis. Thirteen studies (3969 participants) were included in this meta-analysis. The mean difference of SBP between intervention group and control group was - 7.35 mmHg (P < 0.0001). Subgroup analyses showed the greater reduction of SBP in the "regularly scheduled follow-up cohort" (- 8.89 mmHg) compared with the "as needed follow-up cohort" (- 3.23 mmHg, P < 0.0001). The results revealed that remote follow-up by pharmacists reduced SBP levels in hypertension patients and scheduled remote follow-up may contribute to the effectiveness.

Attenuating Epithelial-to-Mesenchymal Transition in Cancer through Angiopoietin-Like 4 Inhibition in a 3D Tumor Microenvironment Model.

Epithelial-to-mesenchymal transition (EMT) plays a crucial role in metastatic cancer progression, and current research, which relies heavily on 2D monolayer cultures, falls short in recapitulating the complexity of a 3D tumor microenvironment. To address this limitation, a transcriptomic meta-analysis is conducted on diverse cancer types undergoing EMT in 2D and 3D cultures. It is found that mechanotransduction is elevated in 3D cultures and is further intensified during EMT, but not during 2D EMT. This analysis reveals a distinct 3D EMT gene signature, characterized by extracellular matrix remodeling coordinated by angiopoietin-like 4 (Angptl4) along with other canonical EMT regulators. Utilizing hydrogel-based 3D matrices with adjustable mechanical forces, 3D cancer cultures are established at varying physiological stiffness levels. A YAP:EGR-1 mediated up-regulation of Angptl4 expression is observed, accompanied by an upregulation of mesenchymal markers, at higher stiffness during cancer EMT. Suppression of Angptl4 using antisense oligonucleotides or anti-cAngptl4 antibodies leads to a dose-dependent abolishment of EMT-mediated chemoresistance and tumor self-organization in 3D, ultimately resulting in diminished metastatic potential and stunted growth of tumor xenografts. This unique programmable 3D cancer cultures simulate stiffness levels in the tumor microenvironment and unveil Angptl4 as a promising therapeutic target to inhibit EMT and impede cancer progression.

ATP1A1-linked diseases require a malfunctioning protein product from one allele.

Heterozygous germline variants in ATP1A1, the gene encoding the α1 subunit of the Na+/K+-ATPase (NKA), have been linked to diseases including primary hyperaldosteronism and the peripheral neuropathy Charcot-Marie-Tooth disease (CMT). ATP1A1 variants that cause CMT induce loss-of-function of NKA. This heterodimeric (αß) enzyme hydrolyzes ATP to establish transmembrane electrochemical gradients of Na+ and K+ that are essential for electrical signaling and cell survival. Of the 4 catalytic subunit isoforms, α1 is ubiquitously expressed and is the predominant paralog in peripheral axons. Human population sequencing datasets indicate strong negative selection against both missense and protein-null ATP1A1 variants. To test whether haploinsufficiency generated by heterozygous protein-null alleles are sufficient to cause disease, we tested the neuromuscular characteristics of heterozygous Atp1a1+/- knockout mice and their wildtype littermates, while also evaluating if exercise increased CMT penetrance. We found that Atp1a1+/- mice were phenotypically normal up to 18 months of age. Consistent with the observations in mice, we report clinical phenotyping of a healthy adult human who lacks any clinical features of known ATP1A1-related diseases despite carrying a plasma-membrane protein-null early truncation variant, p.Y148*. Taken together, these results suggest that a malfunctioning gene product is required for disease induction by ATP1A1 variants and that if any pathology is associated with protein-null variants, they may display low penetrance or high age of onset.

Effectiveness of Online Team-based Learning for Pharmacists on How to Conduct Clinical Medication Reviews for Old Patients in Japan: A Randomized Controlled Trial.

BACKGROUND/AIM: This study aimed to determine the effectiveness of online team-based learning (TBL) and the factors influencing dropouts from online TBL for pharmacists on how to conduct clinical medication reviews for older adults. PARTICIPANTS AND METHODS: All participants were randomly assigned to the TBL or non-TBL group by using a random number sequence table matched by their years of experience working as a pharmacist. The primary outcome was whether the score on the team readiness assurance test (TRAT) in the TBL group differed from that on the second individual readiness assurance test (IRAT) in the non-TBL group. The secondary outcome was to identify factors contributing to dropouts from the online TBL program. RESULTS: The TRAT score in the TBL group was significantly higher than the second IRAT score in the non-TBL group during the first session (p=0.010). There were no differences in TRAT and IRAT scores between groups in two subsequent sessions. Logistic regression analysis revealed that less than 10 years of pharmacy experience was a contributor to dropouts (p=0.039), whereas experience in home-based care prevented dropouts (p=0.026) in our online TBL program. CONCLUSION: This study revealed the short-term usefulness of online TBL on medication reviews for older adults and elucidated the factors related to dropouts. Although instructors should provide positive feedback to participants with insufficient experience in pharmacy practice and home-based care, online TBL has the potential to improve educational effectiveness for community pharmacists during the COVID-19 pandemic.

Impact of a Virtual Game, 'Name That Band,' on Older People's and PharmD Students' Feelings of Social Isolation During COVID-19.

Background Prior to the COVID-19 pandemic, PharmD students at the University of Arizona (UArizona) had a long-standing relationship with the older people at St. Luke's Home, a local Eden Alternative assisted-living community. Hosting community engagement programs for assisted-living residents was challenging with COVID-19 precautions and older individuals suffering from social isolation and loneliness. Objective To determine the impact of playing a virtual game, 'Name That Band,' on older people's and PharmD students' feelings of social isolation during the COVID-19 pandemic. Methods Questionnaires were administered before and after a virtual game to residents at St. Luke's Home and PharmD students at UArizona. Participants were asked about their mood before COVID-19 and pre-and postgame, as well as their social interactions and feelings of loneliness using the Modified UCLA Three-Item Loneliness Scale, which assesses a composite score of lack of companionship, feelings of being left out, and isolation. Results Fifteen older people and 11 students participated in the game (N = 26). All participants completed the pregame survey and 25 completed the postgame survey. The older people reported fewer feelings of isolation and loneliness (measured by a reduction in UCLA Loneliness Scale score) postgame compared with pregame. The students reported a higher total UCLA Loneliness Scale score during the pandemic than prepandemic, but there was no difference in their scores postgame compared with pregame. More older people and students reported feeling 'happy' after playing the virtual game together compared with before the pandemic and before playing. The aspect of the activity that helped older people and students feel more socially engaged was playing a game. Conclusion A social intervention using a virtual game may be a tool that can be used to decrease feelings of isolation and increase engagement for older people residing in an assisted-living community.

Cultural and translation challenges in assessing health literacy among immigrants from the former Soviet Union.

Health literacy is an important foundation for health promotion and an under-recognized risk factor for immigrant and refugee groups. Yet measuring health literacy among diverse ethnic and linguistic populations presents complex challenges. We describe cultural and translation challenges encountered in measuring health literacy among Russian-speaking immigrants to the USA and offer a mixed-methods approach to understanding them. The Rx-Health Literacy (RxHL) study used cross-sectional quantitative and qualitative data to examine health literacy and medication adherence among five cultural and four language groups (Latinx, Vietnamese, African-American, Russian-speaking immigrant and White American) who are patients at Caring Health Center, a federally qualified health center in Springfield, MA. We translated an existing health literacy scale into Russian and Vietnamese and examined item difficulty across cultural groups. We conducted qualitative cognitive interviews to learn more about Russian speakers' understandings of the scale. Health literacy scores varied by cultural group, and the range of correct responses was much greater among Russian speakers than in other groups. Percentage correct varied by 69.7% for Russian speakers, compared with 25.0-44.0% for other groups. These findings indicate greater variability in health literacy levels among this group compared with others. Cognitive interviews with Russian-speaking participants revealed multiple interpretations of several items, suggesting that the English version of the scale contained embedded meanings associated with an American health care context that were not captured in the translated instrument. Combining qualitative and quantitative research methods allows for greater insight into contextual and translation factors that may shape the results of translated instruments in unanticipated ways.

YWHAG Deficiency Disrupts the EMT-Associated Network to Induce Oxidative Cell Death and Prevent Metastasis.

Metastasis involves epithelial-to-mesenchymal transition (EMT), a process that is regulated by complex gene networks, where their deliberate disruption may yield a promising outcome. However, little is known about mechanisms that coordinate these metastasis-associated networks. To address this gap, hub genes with broad engagement across various human cancers by analyzing the transcriptomes of different cancer cell types undergoing EMT are identified. The oncogenic signaling adaptor protein tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma (YWHAG) is ranked top for its clinical relevance and impact. The cellular kinome and transcriptome data are surveyed to construct the regulome of YWHAG, revealing stress responses and metabolic processes during cancer EMT. It is demonstrated that a YWHAG-dependent cytoprotective mechanism in the regulome is embedded in EMT-associated networks to protect cancer cells from oxidative catastrophe through enhanced autophagy during EMT. YWHAG deficiency results in a rapid accumulation of reactive oxygen species (ROS), delayed EMT, and cell death. Tumor allografts show that metastasis potential and overall survival time are correlated with the YWHAG expression level of cancer cell lines. Metastasized tumors have higher expression of YWHAG and autophagy-related genes than primary tumors. Silencing YWHAG diminishes primary tumor volumes, prevents metastasis, and prolongs the median survival period of the mice.

Community-Based Research: Interviewing Older People in Community Pharmacies.

Objective Community pharmacists play an important role in providing many essential services to older adult patients. This study aimed to assess participants' awareness and utilization of current services provided by the community pharmacy and to identify preferences for innovative strategies and services related to healthy aging. Design This is community-based research using interviews with older people in community pharmacies. Student pharmacists performed the interviews, asking 11 questions developed by the research team. The interview questions included services currently provided by the community pharmacy to determine patient awareness and use. Setting One-on-one structured interviews with participants 50 years of age and older were conducted at community pharmacies in Arizona. Results A total of 53 older people (54.7% female) participated, with most patients knowledgeable about current pharmacy services and 69.7% using at least one service. When asked if they would participate in innovative services, more than half of those interviewed (56.6%) were interested in medication side effect screening and education, and 54.7% would want to participate in medication review with drug interaction screening. Almost half were interested in lifestyle education for healthy aging in nutrition and physical activities (49.1%) and medication disposal (47.2%). Most participants preferred to communicate in person with their pharmacists, but some showed interest in mobile phone texts and calls. Conclusion Community pharmacies may be a viable setting to provide novel services to promote healthy aging among older people, particularly medication side effect and drug interaction screenings and education.

Improving a Leadership Scale: Applying Rasch Analysis to Student Pharmacists' Attitudes and Beliefs About Leadership.

OBJECTIVE: Leadership development is necessary for student pharmacists to become pharmacist leaders, but no readily usable standard measurement of student attitudes toward and beliefs about leadership exists. To assess the reliability and validity evidence for using the Leadership Attitudes and Beliefs Scale (LABS-III), originally developed and validated in Malaysia, for use with student pharmacists in the United States. METHODS: The 2-unit leadership course was piloted among second- and third-year students in a public college of pharmacy with a 4-year doctor of pharmacy curriculum. The participating students completed the LABS-III during the first and last classes as part of a quality improvement measure for course enhancement. Rasch analysis was then used to assess the reliability and validity evidence for the LABS-III. RESULTS: A total of 24 students participated in the pilot course. The pre and postcourse surveys had 100% and 92% response rates, respectively. After Rasch analysis model fit was achieved, the item separation for the 14 nonextreme items was 2.19 with an item reliability of 0.83. The person separation index was 2.16 with a person reliability of 0.82. CONCLUSION: The Rasch analysis revealed that the number of LABS-III items should be decreased and that the 3-point response scale should be used to improve functionality and use in classroom settings for PharmD students in the United States. Further research is needed to augment the reliability and validity evidence of the modified instrument for use at other United States colleges of pharmacy.

Site-specific R-loops induce CGG repeat contraction and fragile X gene reactivation.

Here, we describe an approach to correct the genetic defect in fragile X syndrome (FXS) via recruitment of endogenous repair mechanisms. A leading cause of autism spectrum disorders, FXS results from epigenetic silencing of FMR1 due to a congenital trinucleotide (CGG) repeat expansion. By investigating conditions favorable to FMR1 reactivation, we find MEK and BRAF inhibitors that induce a strong repeat contraction and full FMR1 reactivation in cellular models. We trace the mechanism to DNA demethylation and site-specific R-loops, which are necessary and sufficient for repeat contraction. A positive feedback cycle comprising demethylation, de novo FMR1 transcription, and R-loop formation results in the recruitment of endogenous DNA repair mechanisms that then drive excision of the long CGG repeat. Repeat contraction is specific to FMR1 and restores the production of FMRP protein. Our study therefore identifies a potential method of treating FXS in the future.

ATP1A1 -linked diseases require a malfunctioning protein product from one allele.

Heterozygous germline variants in ATP1A1 , the gene encoding the α1 subunit of the Na + /K + -ATPase (NKA), have been linked to diseases including primary hyperaldosteronism and the peripheral neuropathy Charcot-Marie-Tooth disease (CMT). ATP1A1 variants that cause CMT induce loss-of-function of NKA. This heterodimeric (αß) enzyme hydrolyzes ATP to establish transmembrane electrochemical gradients of Na + and K + that are essential for electrical signaling and cell survival. Of the 4 catalytic subunit isoforms, α1 is ubiquitously expressed and is the predominant paralog in peripheral axons. Human population sequencing datasets indicate strong negative selection against both missense and protein-null ATP1A1 variants. To test whether haploinsufficiency generated by heterozygous protein-null alleles are sufficient to cause disease, we tested the neuromuscular characteristics of heterozygous Atp1a1 +/- knockout mice and their wildtype littermates, while also evaluating if exercise increased CMT penetrance. We found that Atp1a1 +/- mice were phenotypically normal up to 18 months of age. Consistent with the observations in mice, we report clinical phenotyping of a healthy adult human who lacks any clinical features of known ATP1A1 -related diseases despite carrying a protein-null early truncation variant, p.Y148*. Taken together, these results suggest that a malfunctioning gene product is required for disease induction by ATP1A1 variants and that if any pathology is associated with protein-null variants, they may display low penetrance or high age of onset.

Efficacy of Ascorbic Acid, Thiamine, and Hydrocortisone Combination Therapy: Meta-analysis of Randomized Controlled Trials.

BACKGROUND/AIM: Sepsis is a life-threatening biological condition that induces systemic tissue and organ dysfunction and confers a high mortality risk. Although the use of hydrocortisone in combination with ascorbic acid and thiamine (HAT therapy) significantly reduced mortality from sepsis or septic shock in a previous study, it did not improve mortality in subsequent randomized controlled trials (RCTs). Therefore, no definitive conclusion has been established on the benefits of HAT therapy for sepsis or septic shock. We performed a meta-analysis to assess the treatment outcomes of HAT therapy in patients with sepsis or septic shock. PATIENTS AND METHODS: We searched databases (PubMed/MEDLINE, Embase, Scopus and Cochrane Library) for RCTs using the terms "ascorbic acid", "thiamine", "sepsis", "septic shock", and "RCT". The primary outcome of this meta-analysis was the mortality rate, and the secondary outcomes were the incidence of new-onset acute renal injury (AKI), intensive care unit (ICU) length of stay (ICU-LOS), change in the Sequential Organ Failure Assessment (SOFA) score within 72 hours, and duration of vasopressor use. RESULTS: Nine RCTs were identified and included in the outcome evaluation. HAT therapy did not improve the 28-day and ICU mortality, new-onset AKI, ICU-LOS, or SOFA scores. However, HAT therapy significantly shortened the duration of vasopressor use. CONCLUSION: HAT therapy did not improve mortality, the SOFA score, renal injury, or ICU-LOS. Further studies are needed to confirm whether it shortens the duration of vasopressor use.

Targeting RNA with small molecules: lessons learned from Xist RNA.

Although more than 98% of the human genome is noncoding, nearly all drugs on the market target one of about 700 disease-related proteins. However, an increasing number of diseases are now being attributed to noncoding RNA and the ability to target them would vastly expand the chemical space for drug development. We recently devised a screening strategy based upon affinity-selection mass spectrometry and succeeded in identifying bioactive compounds for the noncoding RNA prototype, Xist. One such compound, termed X1, has drug-like properties and binds specifically to the RepA motif of Xist in vitro and in vivo. Small-angle X-ray scattering analysis reveals that X1 changes the conformation of RepA in solution, thereby explaining the displacement of cognate interacting protein factors (PRC2 and SPEN) and inhibition of X-chromosome inactivation. In this Perspective, we discuss lessons learned from these proof-of-concept experiments and suggest that RNA can be systematically targeted by drug-like compounds to disrupt RNA structure and function.

Cohesin controls X chromosome structure remodeling and X-reactivation during mouse iPSC-reprogramming.

Reactivation of the inactive X chromosome is a hallmark epigenetic event during reprogramming of mouse female somatic cells to induced pluripotent stem cells (iPSCs). This involves global structural remodeling from a condensed, heterochromatic into an open, euchromatic state, thereby changing a transcriptionally inactive into an active chromosome. Despite recent advances, very little is currently known about the molecular players mediating this process and how this relates to iPSC-reprogramming in general. To gain more insight, here we perform a RNAi-based knockdown screen during iPSC-reprogramming of mouse fibroblasts. We discover factors important for X chromosome reactivation (XCR) and iPSC-reprogramming. Among those, we identify the cohesin complex member SMC1a as a key molecule with a specific function in XCR, as its knockdown greatly affects XCR without interfering with iPSC-reprogramming. Using super-resolution microscopy, we find SMC1a to be preferentially enriched on the active compared with the inactive X chromosome and that SMC1a is critical for the decompacted state of the active X. Specifically, depletion of SMC1a leads to contraction of the active X both in differentiated and in pluripotent cells, where it normally is in its most open state. In summary, we reveal cohesin as a key factor for remodeling of the X chromosome from an inactive to an active structure and that this is a critical step for XCR during iPSC-reprogramming.