Endogenous Hyaluronan Promotes Intestinal Homeostasis and Protects against Murine Necrotizing Enterocolitis.

Necrotizing enterocolitis (NEC) is a complex, multifactorial gastrointestinal disorder predominantly affecting preterm infants. The pathogenesis of this condition involves a complex interplay between intestinal barrier dysfunction, microbial dysbiosis, and an altered immune response. This study investigates the potential role of endogenous hyaluronan (HA) in both the early phases of intestinal development and in the context of NEC-like intestinal injury.

Analyzing efficiency of a lentiviral shRNA knockdown system in human enteroids using western blot and flow cytometry.

Enteroids are in vitro models to study gastrointestinal pathologies and test personalized therapeutics; however, the inherent complexity of enteroids often renders standard gene editing approaches ineffective. Here, we introduce a refined lentiviral transfection protocol, ensuring sufficient lentiviral engagement with enteroids while considering spatiotemporal growth variability throughout the extracellular matrix. Additionally, we highlight a selection process for transduced cells, introduce a protocol to accurately measure transduction efficiency, and explore methodologies to gauge effects of gene knockdown on biological processes.

Role of protein kinase A and A kinase anchoring proteins in buffering and compartmentation of cAMP signalling in human airway smooth muscle cells.

Background And Purpose: In human airway smooth muscle (hASM) cells, not all receptors stimulating cAMP production elicit the same effects. This can only be explained if cAMP movement throughout the cell is restricted, yet the mechanisms involved are not fully understood. Phosphodiesterases (PDEs) contribute to compartmentation of many cAMP responses, but PDE activity alone is predicted to be insufficient if cAMP is otherwise freely diffusible.

Corrigendum: Three-week-old rabbit ventricular cardiomyocytes as a novel system to study cardiac excitation and EC coupling.

[This corrects the article DOI: 10.3389/fphys.2021.

Three-Week-Old Rabbit Ventricular Cardiomyocytes as a Novel System to Study Cardiac Excitation and EC Coupling.

Cardiac arrhythmias significantly contribute to cardiovascular morbidity and mortality. The rabbit heart serves as an accepted model system for studying cardiac cell excitation and arrhythmogenicity. Accordingly, primary cultures of adult rabbit ventricular cardiomyocytes serve as a preferable model to study molecular mechanisms of human cardiac excitation.

Compartmentalized cAMP signaling in cardiac ventricular myocytes.

Activation of different receptors that act by generating the common second messenger cyclic adenosine monophosphate (cAMP) can elicit distinct functional responses in cardiac myocytes. Selectively sequestering cAMP activity to discrete intracellular microdomains is considered essential for generating receptor-specific responses. The processes that control this aspect of compartmentalized cAMP signaling, however, are not completely clear.

Mitochondrial A-kinase anchoring proteins in cardiac ventricular myocytes.

Compartmentation of cAMP signaling is a critical factor for maintaining the integrity of receptor-specific responses in cardiac myocytes. This phenomenon relies on various factors limiting cAMP diffusion. Our previous work in adult rat ventricular myocytes (ARVMs) indicates that PKA regulatory subunits anchored to the outer membrane of mitochondria play a key role in buffering the movement of cytosolic cAMP.

Compartmentation of β -adrenoceptor stimulated cAMP responses by phosphodiesterase types 2 and 3 in cardiac ventricular myocytes.

Background And Purpose: In cardiac myocytes, cyclic AMP (cAMP) produced by both β - and β -adrenoceptors increases L-type Ca channel activity and myocyte contraction. However, only cAMP produced by β -adrenoceptors enhances myocyte relaxation through phospholamban-dependent regulation of the sarco/endoplasmic reticulum Ca ATPase 2 (SERCA2). Here we have tested the hypothesis that stimulation of β -adrenoceptors produces a cAMP signal that is unable to reach SERCA2 and determine what role, if any, phosphodiesterase (PDE) activity plays in this compartmentation.

LITAF (Lipopolysaccharide-Induced Tumor Necrosis Factor) Regulates Cardiac L-Type Calcium Channels by Modulating NEDD (Neural Precursor Cell Expressed Developmentally Downregulated Protein) 4-1 Ubiquitin Ligase.

Background: The turnover of cardiac ion channels underlying action potential duration is regulated by ubiquitination. Genome-wide association studies of QT interval identified several single-nucleotide polymorphisms located in or near genes involved in protein ubiquitination. A genetic variant upstream of LITAF (lipopolysaccharide-induced tumor necrosis factor) gene prompted us to determine its role in modulating cardiac excitation.

Trafficking of the human ether-a-go-go-related gene (hERG) potassium channel is regulated by the ubiquitin ligase rififylin (RFFL).

The QT interval is an important diagnostic feature on surface electrocardiograms because it reflects the duration of the ventricular action potential. A previous genome-wide association study has reported a significant linkage between a single-nucleotide polymorphism ∼11.7 kb downstream of the gene encoding the RING finger ubiquitin ligase rififylin (RFFL) and variability in the QT interval.

RING finger protein RNF207, a novel regulator of cardiac excitation.

Two recent studies (Newton-Cheh, C. et al. (2009) Common variants at ten loci influence QT interval duration in the QTGEN Study.

Progesterone modulates SERCA2a expression and function in rabbit cardiomyocytes.

We recently showed that progesterone treatment abolished arrhythmias and sudden cardiac death in a transgenic rabbit model of long QT syndrome type 2 (LQT2). Moreover, levels of cardiac sarco(endo)plasmic reticulum Ca(2+)-ATPase type 2a (SERCA2a) were upregulated in LQT2 heart extracts. We hypothesized that progesterone treatment upregulated SERCA2a expression, thereby reducing Ca(2+)-dependent arrhythmias in LQT2 rabbits.

Ginger stimulates hematopoiesis via Bmp pathway in zebrafish.

Background: Anemia is a hematologic disorder with decreased number of erythrocytes. Erythropoiesis, the process by which red blood cells differentiate, are conserved in humans, mice and zebrafish. The only known agents available to treat pathological anemia are erythropoietin and its biologic derivatives.

Zebrafish model: worth considering in defining tumor angiogenesis.

The process of angiogenesis is essential for tumor progression and metastasis; however, antiangiogenesis therapy-induced hypoxia and inflammation are perhaps the driving force for tumor escape and metastasis formation, thereby compromising its efficacy. This warrants the complete understanding of the molecular and cellular basis of antiangiogenesis therapy and necessitates the identification of potential signaling events in the host microenvironment, which are involved in tumor angiogenesis and metastasis, to improve the treatment of cancer. In this context, the zebrafish/tumor xenograft model represents an emerging vertebrate system to study the correlation between tumor angiogenesis, inflammation, and metastasis and to better understand the modification of tumor microenvironment by antiangiogenesis therapy.

Discriminating different cancer cells using a zebrafish in vivo assay.

Despite the expanded understanding of tumor angiogenesis phenomenon and how it impacts cancer treatment outcomes, we have yet to develop a robust assay that can quickly, easily, and quantitatively measure tumor-induced angiogenesis. Since the zebrafish/tumor xenograft represents an emerging tool in this regard, the present study strives to capitalize on the ease, effectiveness, and the adaptability of this model to quantify tumor angiogenesis. In order to test a range of responses, we chose two different tumorigenic cell lines, the human non-small cell lung carcinoma (H1299) and the mouse lung adenocarcinoma (CL13).

Restoration of contractility in hyperhomocysteinemia by cardiac-specific deletion of NMDA-R1.

Homocysteine (HCY) activated mitochondrial matrix metalloproteinase-9 and led to cardiomyocyte dysfunction, in part, by inducing mitochondrial permeability (MPT). Treatment with MK-801 [N-methyl-d-aspartate (NMDA) receptor antagonist] ameliorated the HCY-induced decrease in myocyte contractility. However, the role of cardiomyocyte NMDA-receptor 1 (R1) activation in hyperhomocysteinemia (HHCY) leading to myocyte dysfunction was not well understood.

H2S protects against methionine-induced oxidative stress in brain endothelial cells.

Homocysteine (Hcy) causes cerebrovascular dysfunction by inducing oxidative stress. However, to date, there are no strategies to prevent Hcy-induced oxidative damage. Hcy is an H2S precursor formed from methionine (Met) metabolism.

Cardioprotective role of sodium thiosulfate on chronic heart failure by modulating endogenous H2S generation.

Background/aims: Sodium thiosulfate (STS) has been shown to be an antioxidant and calcium solubilizer, but the possible role of STS in dysfunctional ventricles remains unknown. Here, we assessed the effects of STS in the failing heart.

Methods: Heart failure was created by an arteriovenous fistula (AVF).

Homocysteine decreases blood flow to the brain due to vascular resistance in carotid artery.

An elevated level of Homocysteine (Hcy) is a risk factor for vascular dementia and stroke. Cysthathionine beta Synthase (CBS) gene is involved in the clearance of Hcy. Homozygous individuals for (CBS-/-) die early, but heterozygous for (CBS-/+) survive with high levels of Hcy.

Role of copper and homocysteine in pressure overload heart failure.

Elevated levels of homocysteine (Hcy) (known as hyperhomocysteinemia HHcy) are involved in dilated cardiomyopathy. Hcy chelates copper and impairs copper-dependent enzymes. Copper deficiency has been linked to cardiovascular disease.

Mitochondrial matrix metalloproteinase activation decreases myocyte contractility in hyperhomocysteinemia.

Cardiomyocyte N-methyl-d-aspartate receptor-1 (NMDA-R1) activation induces mitochondrial dysfunction. Matrix metalloproteinase protease (MMP) induction is a negative regulator of mitochondrial function. Elevated levels of homocysteine [hyperhomocysteinemia (HHCY)] activate latent MMPs and causes myocardial contractile abnormalities.

GABAA receptor agonist mitigates homocysteine-induced cerebrovascular remodeling in knockout mice.

Individuals with homozygous deficiency in cystathionine-beta-synthase (CBS) develop high levels of homocysteine in plasma, a condition known as homocysteinuria. Mental retardation ensues with death in teens; the heterozygous live normally but develop vascular dementia and Alzheimer's disease (AD) in later part of life. The treatment with muscimol, a gamma amino butyric acid receptor-A (GABA(A)) agonist, mitigates the AD syndrome and vascular dementia.

Mitochondrial MMP activation, dysfunction and arrhythmogenesis in hyperhomocysteinemia.

Chronic volume/pressure overload-induced heart failure augments oxidative stress and activates matrix metalloproteinase which causes endocardial endothelial-myocyte (EM) uncoupling eventually leading to decline in myocardial systolic and diastolic function. The elevated levels of homocysteine (Hcy), hyperhomocysteinemia (HHcy), are associated with decline in cardiac performance. Hcy impairs the EM functions associated with the induction of ventricular hypertrophy leading to cardiac stiffness and diastolic heart failure.

Renal mitochondrial damage and protein modification in type-2 diabetes.

Although mitochondrial reduction-oxidation (redox) stress and increase in membrane permeability play an important role in diabetic-associated renal microvasculopathies, it is unclear whether the intra-renal mitochondrial oxidative stress induces mitochondrial protein modifications, leading to increase mitochondrial membrane permeability. The hypothesis is that mitochondrial oxidative stress induces mitochondrial protein modification and leakage in the mitochondrial membrane in type-2 diabetes. The present study was conducted to determine the involvement of intra-renal mitochondrial oxidative stress in mitochondrial protein modifications and modulation of membrane permeability in the setting of type-2 diabetes.