Fibronectin Extra Domains tune cellular responses and confer topographically distinct features to fibril networks.

Cellular fibronectin (FN; also known as FN1) variants harboring one or two alternatively spliced so-called extra domains (EDB and EDA) play a central bioregulatory role during development, repair processes and fibrosis. Yet, how the extra domains impact fibrillar assembly and function of the molecule remains unclear. Leveraging a unique biological toolset and image analysis pipeline for direct comparison of the variants, we demonstrate that the presence of one or both extra domains impacts FN assembly, function and physical properties of the matrix. When presented to FN-null fibroblasts, extra domain-containing variants differentially regulate pH homeostasis, survival and TGF-ß signaling by tuning the magnitude of cellular responses, rather than triggering independent molecular switches. Numerical analyses of fiber topologies highlight significant differences in variant-specific structural features and provide a first step for the development of a generative model of FN networks to unravel assembly mechanisms and investigate the physical and functional versatility of extracellular matrix landscapes.This article has an associated First Person interview with the first author of the paper.

Browning of human adipocytes requires KLF11 and reprogramming of PPARγ superenhancers.

Long-term exposure to peroxisome proliferator-activated receptor γ (PPARγ) agonists such as rosiglitazone induces browning of rodent and human adipocytes; however, the transcriptional mechanisms governing this phenotypic switch in adipocytes are largely unknown. Here we show that rosiglitazone-induced browning of human adipocytes activates a comprehensive gene program that leads to increased mitochondrial oxidative capacity. Once induced, this gene program and oxidative capacity are maintained independently of rosiglitazone, suggesting that additional browning factors are activated. Browning triggers reprogramming of PPARγ binding, leading to the formation of PPARγ "superenhancers" that are selective for brown-in-white (brite) adipocytes. These are highly associated with key brite-selective genes. Based on such an association, we identified an evolutionarily conserved metabolic regulator, Kruppel-like factor 11 (KLF11), as a novel browning transcription factor in human adipocytes that is required for rosiglitazone-induced browning, including the increase in mitochondrial oxidative capacity. KLF11 is directly induced by PPARγ and appears to cooperate with PPARγ in a feed-forward manner to activate and maintain the brite-selective gene program.

Total Synthesis of Aqabamycin G, a Nitrophenyl Indolylmaleimide Marine Alkaloid from Vibrio sp. WMBA.

The first total synthesis of the marine alkaloid aqabamycin G is disclosed. The synthetic sequence involved the stepwise addition to maleimide of an indole motif and a substituted diazo-benzenoid unit derived from acetaminophen. An alternative strategy using a protected phenol is also reported.

Native mitral valve staphylococcus endocarditis with a very unusual complication: Ruptured posterior mitral valve leaflet aneurysm.

Infective endocarditis (IE) is a life-threatening disease associated with in-hospital mortality of nearly one in five cases. IE can destroy valvular tissue, which may rarely progress to aneurysm formation, most commonly at the anterior leaflet in instances of mitral valve involvement. We present a remarkable case of a patient with IE and a rare complication of a ruptured aneurysm of the posterior leaflet of the mitral valve. Two- and Three-dimensional transesophageal echocardiography, intra-operative videography, and histopathologic analysis revealed disruption at this unusual location-at the junction of the P2 and P3 scallops, surrounded by an annular abscess.

New Strategies Protecting from Ischemia/Reperfusion.

This Special Issue aims to highlight new avenues in the management of Ischemia/Reperfusion (I/R) injury [...].

Akt Inhibition as Preconditioning Treatment to Protect Kidney Cells against Anoxia.

Lesions issued from the ischemia/reperfusion (I/R) stress are a major challenge in human pathophysiology. Of human organs, the kidney is highly sensitive to I/R because of its high oxygen demand and poor regenerative capacity. Previous studies have shown that targeting the hypusination pathway of eIF5A through GC7 greatly improves ischemic tolerance and can be applied successfully to kidney transplants. The protection process correlates with a metabolic shift from oxidative phosphorylation to glycolysis. Because the protein kinase B Akt is involved in ischemic protective mechanisms and glucose metabolism, we looked for a link between the effects of GC7 and Akt in proximal kidney cells exposed to anoxia or the mitotoxic myxothiazol. We found that GC7 treatment resulted in impaired Akt phosphorylation at the Ser473 and Thr308 sites, so the effects of direct Akt inhibition as a preconditioning protocol on ischemic tolerance were investigated. We evidenced that Akt inhibitors provide huge protection for kidney cells against ischemia and myxothiazol. The pro-survival effect of Akt inhibitors, which is reversible, implied a decrease in mitochondrial ROS production but was not related to metabolic changes or an antioxidant defense increase. Therefore, the inhibition of Akt can be considered as a preconditioning treatment against ischemia.

Modulation of the inflammatory response to LPS by the recruitment and activation of brown and brite adipocytes in mice.

Numerous studies have shown that the recruitment and activation of thermogenic adipocytes, which are brown and beige/brite, reduce the mass of adipose tissue and normalize abnormal glycemia and lipidemia. However, the impact of these adipocytes on the inflammatory state of adipose tissue is still not well understood, especially in response to endotoxemia, which is a major aspect of obesity and metabolic diseases. First, we analyzed the phenotype and metabolic function of white and brite primary adipocytes in response to lipopolysaccharide (LPS) treatment in vitro. Then, 8-wk-old male BALB/c mice were treated for 1 wk with a ß3-adrenergic receptor agonist (CL316,243, 1 mg/kg/day) to induce recruitment and activation of brown and brite adipocytes and were subsequently injected with LPS (Escherichia coli lipopolysaccharide, 100 µg/mouse ip) to generate acute endotoxemia. The metabolic and inflammatory parameters of the mice were analyzed 6 h later. Our results showed that in response to LPS, thermogenic activity promoted a local anti-inflammatory environment with high secretion of IL-1 receptor antagonist (IL-1RA) without affecting other anti- or proinflammatory cytokines. Interestingly, activation of brite adipocytes reduced the LPS-induced secretion of leptin. However, thermogenic activity and adipocyte function were not altered by LPS treatment in vitro or by acute endotoxemia in vivo. In conclusion, these results suggest an IL-1RA-mediated immunomodulatory activity of thermogenic adipocytes specifically in response to endotoxemia. This encourages potential therapy involving brown and brite adipocytes for the treatment of obesity and associated metabolic diseases.NEW & NOTEWORTHY Recruitment and activation of brown and brite adipocytes in the adipose tissue of mice lead to a local low-grade anti-inflammatory phenotype in response to acute endotoxemia without alteration of adipocyte phenotype and function.

Oxytocin Controls Chondrogenesis and Correlates with Osteoarthritis.

This study investigated the relationship of oxytocin (OT) to chondrogenesis and osteoarthritis (OA). Human bone marrow and multipotent adipose-derived stem cells were cultured in vitro in the absence or presence of OT and assayed for mRNA transcript expression along with histological and immunohistochemical analyses. To study the effects of OT in OA in vivo, a rat model and a human cohort of 63 men and 19 women with hand OA and healthy controls, respectively, were used. The baseline circulating OT, interleukin-6, leptin, and oestradiol levels were measured, and hand X-ray examinations were performed for each subject. OT induced increased aggrecan, collagen (Col) X, and cartilage oligomeric matrix protein mRNA transcript levels in vitro, and the immunolabelling experiments revealed a normalization of Sox9 and Col II protein expression levels. No histological differences in lesion severity were observed between rat OA groups. In the clinical study, a multivariate analysis adjusted for age, body mass index, and leptin levels revealed a significant association between OA and lower levels of OT (odds ratio = 0.77; p = 0.012). Serum OT levels are reduced in patients with hand OA, and OT showed a stimulatory effect on chondrogenesis. Thus, OT may contribute to the pathophysiology of OA.

The 6π-azaelectrocyclization of azatrienes. Synthetic applications in natural products, bioactive heterocycles, and related fields.

Covering: 2006 to 2018 The application of the 6π-azaelectrocyclization of azatrienes as a key strategy for the synthesis of natural products, their analogs and related bioactive or biomedically-relevant compounds (from 2006 to date) is comprehensively reviewed. Details about reaction optimization studies, relevant reaction mechanisms and conditions are also discussed.

Impact of dietary ω3 polyunsaturated fatty acid supplementation on brown and brite adipocyte function.

The recent characterization of functional brown adipose tissue in adult humans has opened new perspectives for regulation of energy expenditure with respect to obesity and diabetes. Furthermore, dietary recommendations have taken into account the insufficient dietary intake of ω3 PUFAs and the concomitant excessive intake of ω6 PUFA associated with the occurrence of overweight/obesity. We aimed to study whether ω3 PUFAs could play a role in the recruitment and function of energy-dissipating brown/brite adipocytes. We show that ω3 PUFA supplementation has a beneficial effect on the thermogenic function of adipocytes. In vivo, a low dietary ω6:ω3 ratio improved the thermogenic response of brown and white adipose tissues to ß3-adrenergic stimulation. This effect was recapitulated in vitro by PUFA treatment of hMADS adipocytes. We pinpointed the ω6-derived eicosanoid prostaglandin (PG)F2α as the molecular origin because the effects were mimicked with a specific PGF2α receptor agonist. PGF2α level in hMADS adipocytes was reduced in response to ω3 PUFA supplementation. The recruitment of thermogenic adipocytes is influenced by the local quantity of individual oxylipins, which is controlled by the ω6:ω3 ratio of available lipids. In human nutrition, energy homeostasis may thus benefit from the implementation of a more balanced dietary ω6:ω3 ratio.

Targeting eIF5A Hypusination Prevents Anoxic Cell Death through Mitochondrial Silencing and Improves Kidney Transplant Outcome.

The eukaryotic initiation factor 5A (eIF5A), which is highly conserved throughout evolution, has the unique characteristic of post-translational activation through hypusination. This modification is catalyzed by two enzymatic steps involving deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). Notably, eIF5A may be involved in regulating the lifespan of Drosophila during long-term hypoxia. Therefore, we investigated the possibility of a link between eIF5A hypusination and cellular resistance to hypoxia/anoxia. Pharmacologic targeting of DHPS by N1-guanyl-1,7-diaminoheptane (GC7) or RNA interference-mediated inhibition of DHPS or DOHH induced tolerance to anoxia in immortalized mouse renal proximal cells. Furthermore, GC7 treatment of cells reversibly induced a metabolic shift toward glycolysis as well as mitochondrial remodeling and led to downregulated expression and activity of respiratory chain complexes, features characteristic of mitochondrial silencing. GC7 treatment also attenuated anoxia-induced generation of reactive oxygen species in these cells and in normoxic conditions, decreased the mitochondrial oxygen consumption rate of cultured cells and mice. In rats, intraperitoneal injection of GC7 substantially reduced renal levels of hypusinated eIF5A and protected against ischemia-reperfusion-induced renal injury. Finally, in the preclinical pig kidney transplant model, intravenous injection of GC7 before kidney removal significantly improved graft function recovery and late graft function and reduced interstitial fibrosis after transplant. This unconventional signaling pathway offers an innovative therapeutic target for treating hypoxic-ischemic human diseases and organ transplantation.

Del Nido cardioplegia for minimally invasive aortic valve replacement.

BACKGROUND: We analyzed the impact and safety of del Nido Cardioplegia (DNC) in patients undergoing minimally invasive aortic valve replacement (MIAVR). METHODS: We analyzed all isolated MIAVR replacements from 5/2013-6/2015 excluding re-operative patients. The approach was a hemi-median sternotomy in all patients. Patients were divided into two cohorts, those who received 4:1 crystalloid:blood DNC solution and those in whom standard 1:4 Buckberg-based cardioplegia (WBC) was used. One-to-one propensity case matching of DNC to WBC was performed based on standard risk factors and differences between groups were analyzed using chi-square and non-parametric methods. RESULTS: MIAVR was performed in 181 patients; DNC was used in 59 and WBC in 122. Case matching resulted in 59 patients per cohort. DNC was associated with reduced re-dosing (5/59 (8.5%) versus 39/59 (61.0%), P < 0.001) and less total cardioplegia volume (1290 ± 347 mL vs 2284 ± 828 mL, P < 0.001). Antegrade cardioplegia alone was used in 89.8% (53/59) of DNC patients versus 33.9% (20/59) of WBC patients (P < 0.001). Median bypass and aortic cross-clamp times were similar. Clinical outcomes were similar with respect to post-operative hematocrit, transfusion requirements, need for inotropic/pressor support, duration of intensive care unit stay, re-intubation, length of stay, new onset atrial fibrillation, and mortality. CONCLUSIONS: Del Nido cardioplegia usage during MIAVR minimized re-dosing and the need for retrograde delivery. Patient safety was not compromised with this technique in this group of low-risk patients undergoing MIAVR.

IP-receptor and PPARs trigger the conversion of human white to brite adipocyte induced by carbaprostacyclin.

Brite adipocytes recently discovered in humans are of considerable importance in energy expenditure by converting energy excess into heat. This property could be useful in the treatment of obesity, and nutritional aspects are relevant to this important issue. Using hMADS cells as a human cell model which undergoes a white to a brite adipocyte conversion, we had shown previously that arachidonic acid, the major metabolite of the essential nutrient Ω6-linoleic acid, plays a major role in this process. Its metabolites PGE2 and PGF2 alpha inhibit this process via a calcium-dependent pathway, whereas in contrast carbaprostacyclin (cPGI2), a stable analog of prostacyclin, activates white to brite adipocyte conversion. Herein, we show that cPGI2 generates via its cognate cell-surface receptor IP-R, a cyclic AMP-signaling pathway involving PKA activity which in turn induces the expression of UCP1. In addition, cPGI2 activates the pathway of nuclear receptors of the PPAR family, i.e. PPARα and PPARγ, which act separately from IP-R to up-regulate the expression of key genes involved in the function of brite adipocytes. Thus dual pathways are playing in concert for the occurrence of a browning process of human white adipocytes. These results make prostacyclin analogs as a new class of interesting molecules to treat obesity and associated diseases.

The K+ channel TASK1 modulates ß-adrenergic response in brown adipose tissue through the mineralocorticoid receptor pathway.

Brown adipose tissue (BAT) is essential for adaptive thermogenesis and dissipation of caloric excess through the activity of uncoupling protein (UCP)-1. BAT in humans is of great interest for the treatment of obesity and related diseases. In this study, the expression of Twik-related acid-sensitive K(+) channel (TASK)-1 [a pH-sensitive potassium channel encoded by the potassium channel, 2-pore domain, subfamily K, member 3 (Kcnk3) gene] correlated highly with Ucp1 expression in obese and cold-exposed mice. In addition, Task1-null mice, compared with their controls, became overweight, mainly because of an increase in white adipose tissue mass and BAT whitening. Task1(-/-)-mouse-derived brown adipocytes, compared with wild-type mouse-derived brown adipocytes, displayed an impaired ß3-adrenergic receptor response that was characterized by a decrease in oxygen consumption, Ucp1 expression, and lipolysis. This phenotype was thought to be caused by an exacerbation of mineralocorticoid receptor (MR) signaling, given that it was mimicked by corticoids and reversed by an MR inhibitor. We concluded that the K(+) channel TASK1 controls the thermogenic activity in brown adipocytes through modulation of ß-adrenergic receptor signaling.

Robotic Transcatheter Mitral Valve Replacement Using the Sapien XT in the Setting of Severe Mitral Annular Calcification.

We describe the use of the Sapien XT, placed in the mitral position using a totally endoscopic robotic approach in a 76-year-old man with extensive circumferential mitral calcifications and severe stenosis. The patient was at high risk for traditional open surgery and a large mitral valve annulus prevented safe transcatheter deployment due to size mismatch. Our novel approach offered a minimally invasive technique for native mitral valve replacement in a high-risk patient with anatomical constraints prohibitive to conventional approaches. doi: 10.1111/jocs.12737 (J Card Surg 2016;31:303-305).

MicroRNA-26 family is required for human adipogenesis and drives characteristics of brown adipocytes.

Adipose tissue contains thermogenic adipocytes (i.e., brown and brite/beige) that oxidize nutrients at exceptionally high rates via nonshivering thermogenesis. Its recent discovery in adult humans has opened up new avenues to fight obesity and related disorders such as diabetes. Here, we identified miR-26a and -26b as key regulators of human white and brite adipocyte differentiation. Both microRNAs are upregulated in early adipogenesis, and their inhibition prevented lipid accumulation while their overexpression accelerated it. Intriguingly, miR-26a significantly induced pathways related to energy dissipation, shifted mitochondrial morphology toward that seen in brown adipocytes, and promoted uncoupled respiration by markedly increasing the hallmark protein of brown fat, uncoupling protein 1. By combining in silico target prediction, transcriptomics, and an RNA interference screen, we identified the sheddase ADAM metallopeptidase domain 17 (ADAM17) as a direct target of miR-26 that mediated the observed effects on white and brite adipogenesis. These results point to a novel, critical role for the miR-26 family and its downstream effector ADAM17 in human adipocyte differentiation by promoting characteristics of energy-dissipating thermogenic adipocytes.

A Prospective Randomized Study of Paravertebral Blockade in Patients Undergoing Robotic Mitral Valve Repair.

OBJECTIVE: The aim of this study was to evaluate the addition of paravertebral blockade to general anesthesia in patients undergoing robotic mitral valve repair. DESIGN: A randomized, prospective trial. SETTING: A single tertiary referral academic medical center. PARTICIPANTS: 60 patients undergoing robotic mitral valve surgery. INTERVENTIONS: Patients were randomized to receive 4-level paravertebral blockade with 0.5% bupivicaine before induction of general anesthesia. All patients were given a fentanyl patient-controlled analgesia upon arrival to the intensive care unit, and visual analog scale pain scores were queried for 24 hours. On postoperative day 2, patients were given an anesthesia satisfaction survey. MEASUREMENTS AND MAIN RESULTS: After obtaining institutional review board approval, surgical and anesthetic data were recorded perioperatively and compared between groups. Compared to general anesthesia alone, patients receiving paravertebral blockade and general anesthesia reported significantly less postoperative pain and required fewer narcotics intraoperatively and postoperatively. Patients receiving paravertebral blockade also reported significantly higher satisfaction with anesthesia. Successful extubation in the operating room at the conclusion of surgery was 90% and similar in both groups. Hospital length of stay also was similar. No adverse reactions were reported. CONCLUSIONS: The addition of paravertebral blockade to general anesthesia appears safe and can reduce postoperative pain and narcotic usage in patients undergoing minimally invasive cardiac surgery. These findings were similar to previous studies of patients undergoing thoracic procedures. Paravertebral blockade alone likely does not reduce hospital length of stay. This may be more closely related to early extubation, which is possible with or without paravertebral blockade.

In vitro brown and "brite"/"beige" adipogenesis: human cellular models and molecular aspects.

Brown adipose tissue (BAT) has long been thought to be absent or very scarce in human adults so that its contribution to energy expenditure was not considered as relevant. The recent discovery of thermogenic BAT in human adults opened the field for innovative strategies to combat overweight/obesity and associated diseases. This energy-dissipating function of BAT is responsible for adaptive thermogenesis in response to cold stimulation. In this context, adipocytes can be converted, within white adipose tissue (WAT), into multilocular adipocytes expressing UCP1, a mitochondrial protein that plays a key role in heat production by uncoupling the activity of the respiratory chain from ATP synthesis. These adipocytes have been named "brite" or "beige" adipocytes. Whereas BAT has been studied for a long time in murine models both in vivo and in vitro, there is now a strong demand for human cellular models to validate and/or identify critical factors involved in the induction of a thermogenic program within adipocytes. In this review we will discuss the different human cellular models described in the literature and what is known regarding the regulation of their differentiation and/or activation process. In addition, the role of microRNAs as novel regulators of brown/"brite" adipocyte differentiation and conversion will be depicted. Finally, investigation of both the conversion and the metabolism of white-to-brown converted adipocytes is required for the development of therapeutic strategies targeting overweight/obesity and associated diseases. This article is part of a Special Issue entitled Brown and White Fat: From Signaling to Disease.

Long-term results of mitral valve repair with semi-rigid posterior band annuloplasty.

BACKGROUND AND AIM OF THE STUDY: Optimal repair of the mitral valve involves the implantation of an annuloplasty device to geometrically reshape and/or stabilize the annulus and improve long-term durability. It has been reported previously that trigone-to-trigone semi-rigid posterior band (PB) annuloplasty is associated with excellent short-term outcomes, physiologic motion of the anterior mitral annulus and leaflet, and lower postoperative transvalvular gradients compared to complete ring (CR) annuloplasty. The aim of this retrospective study was to compare the long-term effectiveness of PB and CR annuloplasty in patients with degenerative mitral valve regurgitation (MR). METHODS: Between 1993 and 2010, a total of 1,612 patients with degenerative MR underwent mitral valve repair (MVr) with either PB (n = 1,101) or CR (n = 511). Initially, CR was the annuloplasty device of choice, but after 2001 PB was preferred. A retrospective review of clinical and echocardiographic follow up was performed on these patients. The eight-year cumulative freedom from adverse events were determined by life-table analysis. RESULTS: Hospital mortality was 1.9% overall (n = 30/1612), but 1.3% (12/939) for isolated MVr, and 2.7% (18/673) for MVr with concomitant procedures (p = 0.04). Hospital mortality was similar for both PB (1.9%; 21/1101) and CR (1.8%; 9/511) (p = 0.8). The mean MR grade was reduced from 3.9 +/- 0.3 preoperatively to 0.6 +/- 0.9 at follow up using PB (p < 0.01), and from 3.9 +/- 0.4 to 0.9 +/- 0.9 using CR (p < 0.01). PB was associated with a similar long-term freedom from death (77 +/- 0.03% versus 83 +/- 0.02%; p = 0.4), reoperation (95 +/- 0.01% versus 92 +/- 0.01%; p = 0.06), and reoperation or recurrent severe MR (91 +/- 0.02% versus 92 +/- 0.01%; p = 0.7), and slightly greater freedom from valve-related complications compared to CR (91 +/- 0.02% versus 87 +/- 0.02%; p = 0.02). CONCLUSION: The long-term outcome of mitral valve annuloplasty with PB was comparable to that with CR for degenerative disease. Anterior annuloplasty was found to be unnecessary in this patient population.

Polyamine metabolism in macrophage-adipose tissue function and homeostasis.

Intracellular metabolism is a crucial regulator of macrophage function. Recent evidence revealed that the polyamine pathway and subsequent hypusination of eukaryotic initiation factor 5A (eIF5A) are master regulators of immune cell functions. In brown adipose tissue (BAT), macrophages show an impressive degree of heterogenicity, with specific subsets supporting adaptive thermogenesis during cold exposure. In this review, we discuss the impact of polyamine metabolism on macrophage diversity and function, with a particular focus on their role in adipose tissue homeostasis. Thus, we highlight the exploration of how polyamine metabolism in macrophages contributes to BAT homeostasis as an attractive and exciting new field of research.