Practice variations for fetal and neonatal congenital heart disease within the Children's Hospitals Neonatal Consortium.

BACKGROUND: Many aspects of care for fetuses and neonates with congenital heart disease (CHD) fall outside standard practice guidelines, leading to the potential for significant variation in clinical care for this vulnerable population. METHODS: We conducted a cross-sectional survey of site sponsors of the Children's Hospitals Neonatal Consortium, a multicenter collaborative of 41 Level IV neonatal intensive care units to assess key areas of clinical practice variability for patients with fetal and neonatal CHD. RESULTS: We received responses from 31 centers. Fetal consult services are shared by neonatology and pediatric cardiology at 70% of centers. Three centers (10%) routinely perform fetal magnetic resonance imaging (MRI) for women with pregnancies complicated by fetal CHD. Genetic testing for CHD patients is routine at 76% of centers. Preoperative brain MRI is standard practice at 5 centers (17%), while cerebral NIRS monitoring is regularly used at 14 centers (48%). Use of electroencephalogram (EEG) after major cardiac surgery is routine in 5 centers (17%). Neurodevelopmental follow-up programs are offered at 30 centers (97%). CONCLUSIONS: Many aspects of fetal and neonatal CHD care are highly variable with evolving shared multidisciplinary models. IMPACT: Many aspects of fetal and neonatal CHD care are highly variable. Genetic testing, placental examination, preoperative neuroimaging, and postoperative EEG monitoring carry a high yield of finding abnormalities in patients with CHD and these tests may contribute to more precise prognostication and improve care. Evidence-based standards for prenatal and postnatal CHD care may decrease inter-center variability.

Functional characterization of four ATP-binding cassette transporter A3 gene (ABCA3) variants.

ABCA3 transports phospholipids across lamellar body membranes in pulmonary alveolar type II cells and is required for surfactant assembly. Rare, biallelic, pathogenic ABCA3 variants result in lethal neonatal respiratory distress syndrome and childhood interstitial lung disease. Qualitative functional characterization of ABCA3 missense variants suggests two pathogenic classes: disrupted intracellular trafficking (type I mutant) or impaired ATPase-mediated phospholipid transport into the lamellar bodies (type II mutant). We qualitatively compared wild-type (WT-ABCA3) with four uncharacterized ABCA3 variants (c.418A>C;p.Asn140His, c.3609_3611delCTT;p.Phe1203del, c.3784A>G;p.Ser1262Gly, and c.4195G>A;p.Val1399Met) in A549 cells using protein processing, colocalization with intracellular organelles, lamellar body ultrastructure, and ATPase activity. We quantitatively measured lamellar body-like vesicle diameter and intracellular ABCA3 trafficking using fluorescence-based colocalization. Three ABCA3 variants (p.Asn140His, p.Ser1262Gly, and p.Val1399Met) were processed and trafficked normally and demonstrated well-organized lamellar body-like vesicles, but had reduced ATPase activity consistent with type II mutants. P.Phe1203del was processed normally, had reduced ATPase activity, and well-organized lamellar body-like vesicles, but quantitatively colocalized with both endoplasmic reticulum and lysosomal markers, an intermediate phenotype suggesting disruption of both intracellular trafficking and phospholipid transport. All ABCA3 mutants demonstrated mean vesicle diameters smaller than WT-ABCA3. Qualitative and quantitative functional characterization of ABCA3 variants informs mechanisms of pathogenicity.

Antibiotic ivermectin selectively induces apoptosis in chronic myeloid leukemia through inducing mitochondrial dysfunction and oxidative stress.

Mitochondria has been a promising target in blood cancer given their unique dependencies on mitochondrial functions compared to normal hematopoietic cells. In line with this concept, we show that an anthelminthic drug ivermectin selectively kills chronic myeloid leukemia (CML) cells via inducing mitochondrial dysfunctions and oxidative stress. Ivermectin is significantly more effective in inducing caspase-dependent apoptosis in CML cell line K562 and primary CML CD34 than normal bone marrow (NBM) CD34 cells. Ivermectin also augments in vitro and in vivo efficacy of standard CML tyrosine kinase inhibitors. Mechanistically, ivermectin inhibits respiratory complex I activity and suppresses mitochondrial respiration in K562 and CML CD34 cells. Interestingly, we demonstrate that mitochondrial respiration are lower in NBM CD34 compared to malignant CD34 cells. In addition, ivermectin also induces mitochondrial dysfunctions in NBM CD34 cells in a similar manner as in CML CD34 cells whereas NBM CD34 cells are significantly less sensitive to ivermectin than CML CD34 cells. These suggest that NBM CD34 cells are more tolerable to mitochondrial dysfunctions than CML CD34 cells. Consistently, ivermectin induces higher levels of oxidative stress and damage in CML than normal counterparts. Antioxidant NAC rescues ivermectin's effects, confirming oxidative stress as the mechanism of its action in CML. Our work provides the fundamental evidence to repurpose ivermectin for CML treatment. Our work also highlights the therapeutic value of targeting mitochondria respiration in CML.

Circular RNAs in cell cycle regulation: Mechanisms to clinical significance.

Circular RNAs (circRNAs), a type of non-coding RNA, are single-stranded circularized molecules characterized by high abundance, evolutionary conservation and cell development- and tissue-specific expression. A large body of studies has found that circRNAs exert a wide variety of functions in diverse biological processes, including cell cycle. The cell cycle is controlled by the coordinated activation and deactivation of cell cycle regulators. CircRNAs exert mutifunctional roles by regulating gene expression via various mechanisms. However, the functional relevance of circRNAs and cell cycle regulation largely remains to be elucidated. Herein, we briefly describe the biogenesis and mechanistic models of circRNAs and summarize their functions and mechanisms in the regulation of critical cell cycle modulators, including cyclins, cyclin-dependent kinases and cyclin-dependent kinase inhibitors. Moreover, we highlight the participation of circRNAs in cell cycle-related signalling pathways and the clinical value of circRNAs as promising biomarkers or therapeutic targets in diseases related to cell cycle disorder.

Upregulation of protein kinase cdelta in vascular smooth muscle cells promotes inflammation in abdominal aortic aneurysm.

BACKGROUND: The development of abdominal aortic aneurysms (AAAs) involves a complex interplay of extracellular matrix degradation, inflammation, and apoptosis. We have previously shown that protein kinase Cdelta (PKCdelta) plays a critical role in vascular smooth muscle cell (vSMC) apoptosis in the setting of oxidative stresses. Here, we show that PKCdelta is also involved in the signaling that draws inflammatory cells to aneurismal tissue. MATERIALS AND METHODS: Immunostaining for monocyte chemotactic factor (MCP)-1 and PKCdelta was performed on paraffin-fixed arterial sections. Enzyme-linked immunosorbent assay to detect MCP-1 produced by vSMCs was performed on media from cultured rat A10 cells after cytokine induction with or without the PKCdelta-specific inhibitor rottlerin. Migration of isolated lymphocytes was evaluated in response to media from activated A10 cells. RESULTS: Human AAAs show widespread and elevated expression of PKCdelta that is not seen in normal aortic tissues. Cytokine stimulation of cultured vSMCs induced vigorous production of the key chemotactant MCP-1, the expression of which was PKCdelta dependent. Stimulated vSMCs were capable of inducing the migration of leukocytes, and this effect was also dependent on PKCdelta activity. Staining of human AAA tissue for MCP-1 showed an expression pattern that was identical to that of PKCdelta and smooth muscle specific alpha-actin. CONCLUSIONS: PKCdelta is widely expressed in human AAA vessel walls and mediates MCP-1 expression by vSMCs, which could contribute to the inflammatory process. These findings, coupled with earlier studies of PKCdelta, suggest that PKCdelta plays a central role in the pathogenesis of AAAs and may be a potential target for future therapies.

The sensitivity of chronic myeloid leukemia CD34 cells to Bcr-Abl tyrosine kinase inhibitors is modulated by ceramide levels.

Despite BCR-ABL tyrosine kinase inhibitors (TKIs) improved outcome of patients with chronic myeloid leukemia (CML), resistance still develops when progresses to blast phase (BP). The mechanisms underlying resistance to TKIs are not well understood. In this study, we analyzed ceramide levels in CD34 cells derived from BP-CML patients and healthy donor bone marrow (BM) using liquid chromatography mass spectrometry. We found that ceramide level was significantly lower in BP-CML CD34 compared with normal BM counterparts. BP-CML CD34 ceramide(low) were more resistant to BCR-ABL TKIs compared to BP-CML CD34 ceramide(normal). Both mRNA and proteins levels of sphingomyelin synthase 1 and 2 are lower in BP-CML CD34 ceramide(low) compared to normal BM CD34 cells, suggesting that these two ceramide synthesis enzymes maybe the mechanism of how ceramide level is suppressed. Importantly, up-regulation of cellular ceramide level induces apoptosis of multiple CML cell lines and BP-CML CD34 progenitors. Combination of BCR-ABL TKIs with ceramide analog is synergistic in targeting BP-CML 34 progenitors. Collectively, our work provides evidence that down-regulation of ceramide level is involved in the resistance of BP-CML CD34 progenitors to TKIs treatment. Targeting ceramide metabolism together with BCR-ABL inhibition makes it an attractive addition to the armamentarium in BP-CML treatment.