Mesenchymal stromal/stem cells (MSCs) are clinically useful for cell-based therapy, but concerns regarding their ability to replicate limit their human application. MSCs release extracellular ...vesicles (EVs) that mediate at least in part the paracrine effects of the parental cells. To understand the molecular basis of their biological properties, we characterized the RNA cargo of EVs from porcine adipose-tissue derived MSCs. Comprehensive characterization of mRNA and miRNA gene expression using high-throughput RNA sequencing (RNA-seq) revealed that EVs are selectively enriched for distinct classes of RNAs. For example, EVs preferentially express mRNA for transcription factors (e.g. MDFIC, POU3F1, NRIP1) and genes involved in angiogenesis (e.g. HGF, HES1, TCF4) and adipogenesis (e.g. CEBPA, KLF7). EVs also express Golgi apparatus genes (ARRB1, GOLGA4) and genes involved in TGF-β signaling. In contrast, mitochondrial, calcium signaling, and cytoskeleton genes are selectively excluded from EVs, possibly because these genes remain sequestered in organelles or intracellular compartments. RNA-seq generated reads for at least 386 annotated miRNAs, but only miR148a, miR532-5p, miR378, and let-7f were enriched in EVs compared to MSCs. Gene ontology analysis indicates that these miRNAs target transcription factors and genes that participate in several cellular pathways, including angiogenesis, cellular transport, apoptosis, and proteolysis. Our data suggest that EVs transport gene regulatory information to modulate angiogenesis, adipogenesis, and other cell pathways in recipient cells. These observations may contribute to development of regenerative strategies using EVs to overcome potential complications of cell-based therapy.
Perturbations in skeletal development and bone degeneration may result in reduced bone mass and quality, leading to greater fracture risk. Bone loss is mitigated by bone protective therapies, but ...there is a clinical need for new bone-anabolic agents. Previous work has demonstrated that Ezh2 (enhancer of zeste homolog 2), a histone 3 lysine 27 (H3K27) methyltransferase, suppressed differentiation of osteogenic progenitors. Here, we investigated whether inhibition of Ezh2 can be leveraged for bone stimulatory applications. Pharmacologic inhibition and siRNA knockdown of Ezh2 enhanced osteogenic commitment of MC3T3 preosteoblasts. Next generation RNA sequencing of mRNAs and real time quantitative PCR profiling established that Ezh2 inactivation promotes expression of bone-related gene regulators and extracellular matrix proteins. Mechanistically, enhanced gene expression was linked to decreased H3K27 trimethylation (H3K27me3) near transcriptional start sites in genome-wide sequencing of chromatin immunoprecipitations assays. Administration of an Ezh2 inhibitor modestly increases bone density parameters of adult mice. Furthermore, Ezh2 inhibition also alleviated bone loss in an estrogen-deficient mammalian model for osteoporosis. Ezh2 inhibition enhanced expression of Wnt10b and Pth1r and increased the BMP-dependent phosphorylation of Smad1/5. Thus, these data suggest that inhibition of Ezh2 promotes paracrine signaling in osteoblasts and has bone-anabolic and osteoprotective potential in adults.
Functional variability among human clones of induced pluripotent stem cells (hiPSCs) remains a limitation in assembling high‐quality biorepositories. Beyond inter‐person variability, the root cause ...of intra‐person variability remains unknown. Mitochondria guide the required transition from oxidative to glycolytic metabolism in nuclear reprogramming. Moreover, mitochondria have their own genome (mitochondrial DNA mtDNA). Herein, we performed mtDNA next‐generation sequencing (NGS) on 84 hiPSC clones derived from a cohort of 19 individuals, including mitochondrial and non‐mitochondrial patients. The analysis of mtDNA variants showed that low levels of potentially pathogenic mutations in the original fibroblasts are revealed through nuclear reprogramming, generating mutant hiPSCs with a detrimental effect in their differentiated progeny. Specifically, hiPSC‐derived cardiomyocytes with expanded mtDNA mutations non‐related with any described human disease, showed impaired mitochondrial respiration, being a potential cause of intra‐person hiPSC variability. We propose mtDNA NGS as a new selection criterion to ensure hiPSC quality for drug discovery and regenerative medicine.
Synopsis
Low level of natural heteroplasmy in mitochondrial DNA in parental fibroblasts can be revealed during nuclear reprogramming in both healthy and diseased individuals and is a potential source of intra‐person hiPSC variability.
Low levels of heteroplasmic mitochondrial DNA (mtDNA) Global Private Mutations (GPMs) from the original fibroblasts are revealed in hiPSC clones during nuclear reprogramming.
hiPSC‐derived cardiomyocytes with GPMs show reduced mitochondrial oxygen consumption compared with isogenic wild‐type controls.
Universal heteroplasmy is a potential source of intra‐person hiPSC variability.
mtDNA next‐generation sequencing is a new hiPSCs selection criterion with the capacity to identify hiPSC clones representative of the patient for further applications.
Low level of natural heteroplasmy in mitochondrial DNA in parental fibroblasts can be revealed during nuclear reprogramming in both healthy and diseased individuals and is a potential source of intra‐person hiPSC variability.
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-associated viral infection (coronavirus disease 2019, COVID-19) is a virulent, contagious viral pandemic that is affecting populations ...worldwide. As with any airborne viral respiratory infection, surgical and non-surgical patients may be affected.
Review and synthesis of pertinent English-language literature pertaining to COVID-19 infection among adult patients.
COVID-19 disease that requires hospitalization results in critical illness approximately 25% of the time and requires mechanical ventilation with positive airway pressure. Acute kidney injury, a marked hypercoagulable state, and sometimes myocarditis can be features of COVID-19 in addition to the characteristic severe acute lung injury. Even if not among the most seriously afflicted, older patients with medical comorbidities are both predisposed to infection and risk increased morbidity and mortality, however, all persons presenting for surgical intervention should be suspected of infection (and thus transmissibility) even if asymptomatic. Although most elective surgery has been curtailed by administrative or governmental fiat, patients will still need urgent or emergency operative intervention for time-sensitive disease processes such as malignant neoplasia or for true emergencies such as perforated viscus or traumatic injury. It is possible to provide safe surgical care for SARS-CoV-2-positive patients and minimize nosocomial transmission to healthcare workers.
This guidance will facilitate appropriate protection of patients and staff, and maintenance of infection control measures to assist surgical personnel and facilities to prepare for COVID-19-infected adult patients requiring urgent or emergent operative intervention and to provide optimal patient care.
Long-QT syndrome (LQTS) may result in syncope, seizures, or sudden cardiac arrest. Although 16 LQTS-susceptibility genes have been discovered, 20% to 25% of LQTS remains genetically elusive.
We ...performed whole-exome sequencing child-parent trio analysis followed by recessive and sporadic inheritance modeling and disease-network candidate analysis gene ranking to identify a novel underlying genetic mechanism for LQTS. Subsequent mutational analysis of the candidate gene was performed with polymerase chain reaction, denaturing high-performance liquid chromatography, and DNA sequencing on a cohort of 33 additional unrelated patients with genetically elusive LQTS. After whole-exome sequencing and variant filtration, a homozygous p.D18fs*13 TRDN-encoded triadin frameshift mutation was discovered in a 10-year-old female patient with LQTS with a QTc of 500 milliseconds who experienced recurrent exertion-induced syncope/cardiac arrest beginning at 1 year of age. Subsequent mutational analysis of TRDN revealed either homozygous or compound heterozygous frameshift mutations in 4 of 33 unrelated cases of LQTS (12%). All 5 TRDN-null patients displayed extensive T-wave inversions in precordial leads V1 through V4, with either persistent or transient QT prolongation and severe disease expression of exercise-induced cardiac arrest in early childhood (≤3 years of age) and required aggressive therapy. The overall yield of TRDN mutations was significantly greater in patients ≤10 years of age (5 of 10, 50%) compared with older patients (0 of 24, 0%; P=0.0009).
We identified TRDN as a novel underlying genetic basis for recessively inherited LQTS. All TRDN-null patients had strikingly similar phenotypes. Given the recurrent nature of potential lethal arrhythmias, patients fitting this phenotypic profile should undergo cardiac TRDN genetic testing.
Sudden infant death syndrome (SIDS) is a leading cause of postneonatal mortality. Genetic heart diseases (GHDs) underlie some cases of SIDS.
This study aimed to determine the spectrum and prevalence ...of GHD-associated mutations as a potential monogenic basis for SIDS.
A cohort of 419 unrelated SIDS cases (257 male; average age 2.7 ± 1.9 months) underwent whole exome sequencing and a targeted analysis of 90 GHD-susceptibility genes. The yield of “potentially informative,” ultra-rare variants (minor allele frequency <0.00005) in GHD-associated genes was assessed.
Overall, 53 of 419 (12.6%) SIDS cases had ≥1 “potentially informative,” GHD-associated variant. The yield was 14.9% (21 of 141) for mixed-European ancestry cases and 11.5% (32 of 278) for European ancestry SIDS cases. Infants older than 4 months were more likely to host a “potentially informative” GHD-associated variant. There was significant overrepresentation of ultra-rare nonsynonymous variants in European SIDS cases (18 of 278 6.5%) versus European control subjects (30 of 973 3.1%; p = 0.013) when combining all 4 major cardiac channelopathy genes (KCNQ1, KCNH2, SCN5A, and RYR2). According to the American College of Medical Genetics guidelines, only 18 of 419 (4.3%) SIDS cases hosted a “pathogenic” or “likely pathogenic” variant.
Less than 15% of more than 400 SIDS cases had a “potentially informative” variant in a GHD-susceptibility gene, predominantly in the 4- to 12-month age group. Only 4.3% of cases possessed immediately clinically actionable variants. Consistent with previous studies, ultra-rare, nonsynonymous variants within the major cardiac channelopathy-associated genes were overrepresented in SIDS cases in infants of European ethnicity. These findings have major implications for the investigation of SIDS cases and families.
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Congenital heart diseases (CHDs), including hypoplastic left heart syndrome (HLHS), are genetically complex and poorly understood. Here, a multidisciplinary platform was established to functionally ...evaluate novel CHD gene candidates, based on whole-genome and iPSC RNA sequencing of a HLHS family-trio. Filtering for rare variants and altered expression in proband iPSCs prioritized 10 candidates. siRNA/RNAi-mediated knockdown in healthy human iPSC-derived cardiomyocytes (hiPSC-CM) and in developing
and zebrafish hearts revealed that LDL receptor-related protein
is required for cardiomyocyte proliferation and differentiation. Consistent with hypoplastic heart defects, compared to patents the proband's iPSC-CMs exhibited reduced proliferation. Interestingly, rare, predicted-damaging LRP2 variants were enriched in a HLHS cohort; however, understanding their contribution to HLHS requires further investigation. Collectively, we have established a multi-species high-throughput platform to rapidly evaluate candidate genes and their interactions during heart development, which are crucial first steps toward deciphering oligogenic underpinnings of CHDs, including hypoplastic left hearts.
HIV endpoint-driven clinical trials in Africa enroll women who are at heightened risk of acquiring HIV. In 2017, the South African Medical Research Council recommended the provision of oral ...pre-exposure prophylaxis (PrEP) in HIV prevention trials, at which time the Evidence for Contraceptive Options and HIV Outcomes trial was ongoing and began to provide PrEP on-site at some trial sites. We interviewed 132 women who initiated PrEP on-site at the Durban, South Africa trial site to explore PrEP use, and conducted phone-based interviews 4–6 months post-trial exit to explore post-trial PrEP access. PrEP uptake was high (42.6%). Among women initiating PrEP on-site, 87.9% felt at risk of acquiring HIV. Most women (> 90%) heard of PrEP for the first time from study staff and three-quarters who initiated PrEP on-site continued at trial-exit. PrEP use declined post-trial exit with more than 50% of women discontinuing PrEP, and barriers relating to access emerged.
MicroRNA (miRNA) profiling is an important step in studying biological associations and identifying marker candidates. miRNA exists in isoforms, called isomiRs, which may exhibit distinct properties. ...With conventional profiling methods, limitations in assay and analysis platforms may compromise isomiR interrogation.
We introduce a comprehensive approach to sequence-oriented isomiR annotation (CASMIR) to allow unbiased identification of global isomiRs from small RNA sequencing data. In this approach, small RNA reads are maintained as independent sequences instead of being summarized under miRNA names. IsomiR features are identified through step-wise local alignment against canonical forms and precursor sequences. Through customizing the reference database, CASMIR is applicable to isomiR annotation across species. To demonstrate its application, we investigated isomiR profiles in normal and neoplastic human colorectal epithelia. We also ran miRDeep2, a popular miRNA analysis algorithm to validate isomiRs annotated by CASMIR. With CASMIR, specific and biologically relevant isomiR patterns could be identified. We note that specific isomiRs are often more abundant than their canonical forms. We identify isomiRs that are commonly up-regulated in both colorectal cancer and advanced adenoma, and illustrate advantages in targeting isomiRs as potential biomarkers over canonical forms.
Studying miRNAs at the isomiR level could reveal new insight into miRNA biology and inform assay design for specific isomiRs. CASMIR facilitates comprehensive annotation of isomiR features in small RNA sequencing data for isomiR profiling and differential expression analysis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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