Littre's Umbilical Hernia in a Child: A Case Report and Scoping Review.

Littre's umbilical hernia (UH) is a rare disease, the third most common Littre hernia. Most case reports interest adult patients. We reported the case of a four-year-old girl with anemia and symptomatic UH, with an incidentally diagnosed Meckel's diverticulum (MD) containing pancreatic ectopic tissue. We reviewed case reports on Littre's umbilical hernia without a date or language restriction. Including our patient, 21 cases were reviewed, of whom 15 (71.4%) were adults and 13 (61.9%) were males. Complicated umbilical hernia occurred in 13 patients (61.9%) and symptomatic MD in two children (9.5%). Investigations preoperatively diagnosed two patients (9.5%). Eighteen patients (85.7%) underwent open surgery, Meckel's diverticulum removal was performed in 18 patients (85.7%), and primary umbilical hernia repair was performed in 16 (76.2%). Ectopic tissue was present in four patients (19.1%), and long-term outcomes were excellent in all patients.

Basal ATP release signals through the P2Y2 receptor to maintain the differentiated phenotype of vascular smooth muscle cells.

BACKGROUND AND AIMS: Vascular smooth muscle cell (VSMC) dedifferentiation contributes substantively to vascular disease. VSMCs spontaneously release low levels of ATP that modulate vessel contractility, but it is unclear if autocrine ATP signaling in VSMCs is critical to the maintenance of the VSMC contractile phenotype. METHODS: We used pharmacological inhibitors to block ATP release in human aortic smooth muscle cells (HASMCs) for studying changes in VSMC differentiation marker gene expression. We employed RNA interference and generated mice with SMC-specific inducible deletion of the P2Y2 receptor (P2Y2R) gene to evaluate resulting phenotypic alterations. RESULTS: HASMCs constitutively release low levels of ATP that when blocked results in a significant decrease in VSMC differentiation marker gene expression, including smooth muscle actin (SMA), smooth muscle myosin heavy chain (SMMHC), SM-22α and calponin. Basal release of ATP represses transcriptional activation of the Krüppel-Like Factor 4 (KFL4) thereby preventing platelet-derived growth factor-BB (PDGF-BB) from inhibiting expression of SMC contractile phenotype markers. SMC-restricted conditional deletion of P2Y2R evoked dedifferentiation characterized by decreases in aortic contractility and contractile phenotype markers expression. This loss was accompanied by a transition to the synthetic phenotype with the acquisition of extracellular matrix (ECM) proteins characteristic of dedifferentiation, such as osteopontin and vimentin. CONCLUSIONS: Our data establish the first direct evidence that an autocrine ATP release mechanism maintains SMC cytoskeletal protein expression by inhibiting VSMCs from transitioning to a synthetic phenotype, and further demonstrate that activation of the P2Y2R by basally released ATP is required for maintenance of the differentiated VSMC phenotype.

Brachial Plexus' Schwannoma in a Child.

Children's schwannoma is a rare condition, generally occurring in a sporadic way. Its aetiology is still not fully understood. We report the case of a 10-year old girl who presented a left shoulder mass, along motility reduction of the left upper limb for 24 months before presentation at our service. A biopsy resection of the mass gave the diagnosis and 6 months after surgical resection, no complication occurred.

[Management of congenital diaphragmatic hernia in sub-Saharan Africa: experience in the Albert Royer National Children's Hospital Center, Senegal]. / Prise en charge de la hernie diaphragmatique congénitale en Afrique sub-Saharienne: l'expérience du Centre Hospitalier National d'Enfants Albert Royer au Sénégal.

Introduction: congenital diaphragmatic hernia has been rarely reported in Africa. It can manifests early or late. Prognosis mainly depends on associated malformations. The purpose of this study is to report our experience in the Albert Royer National Children's Hospital, Dakar, Senegal. Methods: we conducted a retrospective study of patients treated for congenital diaphragmatic hernia between January 2010 and December 2019. Results: twelve patients were enrolled, with an average age of 8.9 months. Bochdalek hernias were detected in 10 patients. The most common symptoms were respiratory symptoms (83.3%), followed by digestive symptoms (41.6%). Thoraco-abdominal X-ray was used to make a diagnosis in all patients. Three patients underwent preoperative stabilization. All patients underwent laparotomy. Hernia sac was found in 10 patients, and 50% of patients had a defect measuring between 5 and 10 cm. The postoperative course was simple in 10 patients; a polymalformed patient died. Conclusion: congenital diaphragmatic hernia is a reality in our environment; it most often manifests beyond the neonatal period. Prognosis is generally good in our context.

Acute appendicitis revealing a giant mesenteric pseudocyst: case report.

Mesenteric pseuodycst is a very rare benign childhood tumor, accounting for less than 1 out of 250,000 hospital admissions. We here report a case of giant mesenteric pseudocyst incidentally detected in a 11-year-old boy with acute appendicitis. He complained of persistent abdominal pain for the past 48 hours. He had a history of intermittent pain for several months. Physical examination showed fever and abdominal pain. Ultrasonography showed large peritoneal fluid related to peritonitis probably of appendicular origin. The patient underwent exploratory laparotomy revealing giant abdominal mesenteric cyst and acute appendicitis. Open resection of the cyst and appendectomy were performed. The diagnosis of uncomplicated acute appendicitis associated with mesenteric pseudocyst was made. Preoperative diagnosis of pseudomesenteric cysts is a clinical challenge. Knowledge is essential and suspicion should be maintained in patients with nonspecific symptoms.

[Epidemiological and lesion aspects of hand fractures in children in the Pediatric Surgery department of the Aristide Le Dantec Hospital in Dakar]. / Aspects epidemiologiques et lesionnels des fractures de la main chez l'enfant au service de Chirurgie Pediatrique du chu Aristide Le Dantec de Dakar.

PURPOSE: Report the epidemiological and lesion aspects of hand bone fractures in children. PATIENTS AND METHOD: We did a retrospective and descriptive study over a 10-year period. This study involved 222 childre nunder the age of 16 with 261 fracture cases. The parameters studied were frequency, age, sex, mechanism, circumstances of fracture, consultation time, data from standard physical examination and x-ray of the hand, and associated lesions. RESULTS: Hand bone fractures accounted for 6.4% of all fractures in children in our service. The average age of the children was 8.5 years with a standard deviation of 4. There was a male predominance with a sex ratio of 2. Domestic accidents led the way with 44.3% of cases. They were followed by playful accidents with 33.94% of cases. Receiving heavy objects and fallingwith hand reception were the most common mechanisms. 62.8% of patients consulted within the first 24 hours. All fractures were in the metacarpals and phalanxes with 31% and 69% of cases, respectively. Head and diaphysis fractures each accounted for 28.1% of cases followed by cervical fractures with 27.8%. Non-displaced fractures accounted for 65% of cases. Associated lesions were found in 10 patients. CONCLUSION: Hand bone fractures are quite common. They often interest the bigchild in the decoy of a domestic or playful accident, by crushing the hand or falling with reception on the hand. Fractures of the phalanxes are the most common while those of carp are absent.

BUT: Rapporter les aspects épidémiologiques et lésionnels des fractures des os de la main chez l'enfant. PATIENTS ET MÉTHODE: Nous avons fait une étude rétrospective et descriptive sur une période de 10 ans. Cette étude concernait 222 enfants âgés de moins de 16 ans et ayant présenté 261 cas de fracture. Les paramètres étudiés étaient la fréquence, l'âge, le sexe, le mécanisme, les circonstances de survenue de la fracture, le délai de consultation, les données de l'examen physique et de la radiographie standard de la main ainsi que les lésions associées. RÉSULTATS: Les fractures des os de la main représentaient 6,4% de l'ensemble des fractures chez l'enfant dans notre service. L'âge moyen des enfants était de 8,5 ans avec un écart-type de 4. On notait une prédominance masculine avec un sexe ratio de 2. Les accidents domestiques arrivaient en tête avec 44,3% des cas. Ils étaient suivis des accidents ludiques avec 33,94% des cas. La réception d'objets lourds et les chutes avec réception sur la main étaient les mécanismes les plus fréquents. 62,8% des patients ont consulté dans les 24 premières heures. Toutes les fractures siégeaient au niveau des métacarpes et des phalanges avec respectivement 31% et 69% des cas. Les fractures de la tête et de la diaphyse représentaient chacune 28,1% des cas suivies des fractures du col avec 27,8%. Les fractures non déplacées représentaient 65 % des cas. Des lésions associées ont été retrouvées chez 10 patients. CONCLUSION: Les fractures des os de la main sont assez fréquentes. Elles intéressent souvent le grand enfant au décours d'un accident domestique ou ludique, par écrasement de la main ou chute avec réception sur la main. Les fractures des phalanges sont les plus fréquentes alors que celles intéressant le carpe sont absentes.

Endothelial pannexin 1-TRPV4 channel signaling lowers pulmonary arterial pressure in mice.

Pannexin 1 (Panx1), an ATP-efflux pathway, has been linked with inflammation in pulmonary capillaries. However, the physiological roles of endothelial Panx1 in the pulmonary vasculature are unknown. Endothelial transient receptor potential vanilloid 4 (TRPV4) channels lower pulmonary artery (PA) contractility and exogenous ATP activates endothelial TRPV4 channels. We hypothesized that endothelial Panx1-ATP-TRPV4 channel signaling promotes vasodilation and lowers pulmonary arterial pressure (PAP). Endothelial, but not smooth muscle, knockout of Panx1 increased PA contractility and raised PAP in mice. Flow/shear stress increased ATP efflux through endothelial Panx1 in PAs. Panx1-effluxed extracellular ATP signaled through purinergic P2Y2 receptor (P2Y2R) to activate protein kinase Cα (PKCα), which in turn activated endothelial TRPV4 channels. Finally, caveolin-1 provided a signaling scaffold for endothelial Panx1, P2Y2R, PKCα, and TRPV4 channels in PAs, promoting their spatial proximity and enabling signaling interactions. These results indicate that endothelial Panx1-P2Y2R-TRPV4 channel signaling, facilitated by caveolin-1, reduces PA contractility and lowers PAP in mice.

[Cryptorchidism in Prune Belly syndrome]. / La Cryptorchidie dans le Syndrome de Prune Belly.

PURPOSE: To analyze the epidemiological, diagnostic, therapeutic and evolutionary aspects of cryptorchidism in Prune Belly syndrome. PATIENTS AND METHOD: This is a retrospective and descriptive study over an 11-year period involving 24 cases of children admitted for cryptorchidism that is part of Prune Belly syndrome in the paediatric surgery department of the Aristide Le Dantec University Hospital in Dakar. We were interested in epidemiological, diagnostic, therapeutic and evolutionary aspects. RESULTS: The incidence of cryptorchidism in Prune Belly syndrome was 2.4 cases per year. The average age of discovery was 1 year and the age of testicular lowering was 20 months. The bilateral form predateed with 91.7% of cases. Simple orchidopexia was practiced in 50% of cases. An orchidopexia using the Fowler-Stephens technique in one time was practiced in 45.8% of cases. A right orchidectomy was needed in 4.2% of cases. Surgical procedures were simple in 47.8% of the lowered testicles. The most common complication was testicular atrophy noted primarily in the Fowler-Stephens technique in a single time. CONCLUSION: Cryptorchidism in Prune Belly syndrome is most often bilateral and the testicle was frequently palpable. His diagnosis remains very late in our context. Given the number of testicular atrophies driven by the Fowler-Stephens technique in one time, it should be abandoned in favour of the Fowler-Stephens technique in two stages.

BUT: Analyser les aspects épidémiologiques, diagnostiques, thérapeutiques et évolutifs de la cryptorchidie dans le syndrome de Prune Belly. PATIENTS ET MÉTHODE: Il s'agit d'une étude rétrospective et descriptive sur une période de 11 ans portant sur 24 cas d'enfants admis pour une cryptorchidie qui entre dans le cadre du syndrome de Prune Belly au service de chirurgie pédiatrique du centre hospitalier universitaire Aristide Le Dantec de Dakar. Nous nous sommes intéressés aux aspects épidémiologiques, diagnostiques, thérapeutiques et évolutifs. RÉSULTATS: L'incidence de la cryptorchidie dans le cadre du syndrome de Prune Belly était de 2,4 cas par an. L'âge moyen de découverte était de 1 an et celui de l'abaissement testiculaire était de 20 mois. La forme bilatérale prédominait avec 91,7% de cas. Une orchidopexie simple a été pratiquée dans 50% des cas. Une orchidopexie selon la technique de Fowler-Stephens en un temps a été pratiquée dans 45,8% des cas. Une orchidectomie droite était nécessaire chez 4,2% des cas. Les suites opératoires étaient simples chez 47,8% des testicules abaissés. La complication la plus fréquente était l'atrophie testiculaire notée essentiellement dans la technique de Fowler-Stephens en un seul temps. CONCLUSION: La cryptorchidie dans le cadre du syndrome de Prune Belly est le plus souvent bilatérale et le testicule était fréquemment palpable. Son diagnostic reste très tardif dans notre contexte. Au vu du nombre d'atrophies testiculaires entraîné par la technique Fowler-Stephens en un temps, elle devrait être abandonnée au profit de la technique de Fowler-Stephens en deux temps.

[Omphalomesenteric fistulas; epidemiological diagnostic and therapeutic features: study of four cases in the Department of Pediatric Surgery at the Aristide Le Dantec University Hospital in Dakar]. / Fistules omphalo-mésenteriques; aspects épidémio logiques, diagnostiques et thérapeutiques: à propos de quatre observations au Service de Chirurgie Pédiatrique du CHU Aristide Le Dantec de Dakar.

This study aims to determine the epidemiological, therapeutic and diagnostic features of omphalomesenteric fistulas (OMF). We conducted a study of four cases over a period of 10 years, from January 2004 to December 2013. The parameters studied were: frequency, age, sex, clinical and radiological signs, therapeutic and evolutionary features. Frequency was 0.4 cases per year. Patients were aged 11 days, 40 days, 45 days and 3 years respectively (three girls and one boy). Clinical examination showed intestinal fluid discharge from the belly button and belly button bud catheterisable in all the cases. The bud was prolapsed in the patient aged 45 days. Fistulography performed in two cases helped to confirm the diagnosis by showing a communication between the fistula and the small intestine. The assessment of malformations revealed congenital cyanogen heart disease with interventricular communication in the newborn aged 45 days, anorectal cloacal malformation associated with urachus fistula in the newborn aged 11 days. All patients underwent surgery. Semicircular periumbilical incision was performed in the absence of associated abdominopelvic malformations. A communication between the fistula and the ileum was found in the majority of cases. Bowel resection with termino-terminal anastomosis was performed in three cases. Cuneiform resection was performed in one case and was completed by complete resection of the urachal fistulous tract and bladder suture, with colostomy in newborn with urachal fistula and anorectal cloacal malformation. The postoperative course was marked by non-febrile seizures in the first child with good evolution and by superficial parietal suppuration followed by death due to cardiac decompensation in the third case. Omphalomesenteric fistula is rare. Diagnosis is based on clinical examination complemented by the fistulography. Surgical treatment using semicircular periumbilical incision gives good results. However, the assessment of malformations is necessary.

TLR3 deficiency exacerbates the loss of epithelial barrier function during genital tract Chlamydia muridarum infection.

PROBLEM: Chlamydia trachomatis infections are often associated with acute syndromes including cervicitis, urethritis, and endometritis, which can lead to chronic sequelae such as pelvic inflammatory disease (PID), chronic pelvic pain, ectopic pregnancy, and tubal infertility. As epithelial cells are the primary cell type productively infected during genital tract Chlamydia infections, we investigated whether Chlamydia has any impact on the integrity of the host epithelial barrier as a possible mechanism to facilitate the dissemination of infection, and examined whether TLR3 function modulates its impact. METHOD OF STUDY: We used wild-type and TLR3-deficient murine oviduct epithelial (OE) cells to ascertain whether C. muridarum infection had any effect on the epithelial barrier integrity of these cells as measured by transepithelial resistance (TER) and cell permeability assays. We next assessed whether infection impacted the transcription and protein function of the cellular tight-junction (TJ) genes for claudins1-4, ZO-1, JAM1 and occludin via quantitative real-time PCR (qPCR) and western blot. RESULTS: qPCR, immunoblotting, transwell permeability assays, and TER studies show that Chlamydia compromises cellular TJ function throughout infection in murine OE cells and that TLR3 deficiency significantly exacerbates this effect. CONCLUSION: Our data show that TLR3 plays a role in modulating epithelial barrier function during Chlamydia infection of epithelial cells lining the genital tract. These findings propose a role for TLR3 signaling in maintaining the integrity of epithelial barrier function during genital tract Chlamydia infection, a function that we hypothesize is important in helping limit the chlamydial spread and subsequent genital tract pathology.

The P2Y2 nucleotide receptor is an inhibitor of vascular calcification.

BACKGROUND AND AIMS: Mutations in the 5'-nucleotidase ecto (NT5E) gene that encodes CD73, a nucleotidase that converts AMP to adenosine, are linked to arterial calcification. However, the role of purinergic receptor signaling in the pathology of intimal calcification is not well understood. In this study, we examined whether extracellular nucleotides acting via P2Y2 receptor (P2Y2R) modulate arterial intimal calcification, a condition highly correlated with cardiovascular morbidity. METHODS: Apolipoprotein E, P2Y2R double knockout mice (ApoE-/-P2Y2R-/-) were used to determine the effect of P2Y2R deficiency on vascular calcification in vivo. Vascular smooth muscle cells (VSMC) isolated from P2Y2R-/- mice grown in high phosphate medium were used to assess the role of P2Y2R in the conversion of VSMC into osteoblasts. Luciferase-reporter assays were used to assess the effect of P2Y2R on the transcriptional activity of Runx2. RESULTS: P2Y2R deficiency in ApoE-/- mice caused extensive intimal calcification despite a significant reduction in atherosclerosis and macrophage plaque content. The ectoenzyme apyrase that degrades nucleoside di- and triphosphates accelerated high phosphate-induced calcium deposition in cultured VSMC. Expression of P2Y2R inhibits calcification in vitro inhibited the osteoblastic trans-differentiation of VSMC. Mechanistically, expression of P2Y2R inhibited Runx2 transcriptional activation of an osteocalcin promoter driven luciferase reporter gene. CONCLUSIONS: This study reveals a role for vascular P2Y2R as an inhibitor of arterial intimal calcification and provides a new mechanistic insight into the regulation of the osteoblastic trans-differentiation of SMC through P2Y2R-mediated Runx2 antagonism. Given that calcification of atherosclerotic lesions is a significant clinical problem, activating P2Y2R may be an effective therapeutic approach for treatment or prevention of vascular calcification.

Endothelial Cell-Specific Deletion of P2Y2 Receptor Promotes Plaque Stability in Atherosclerosis-Susceptible ApoE-Null Mice.

OBJECTIVE: Nucleotide P2Y2 receptor (P2Y2R) contributes to vascular inflammation by increasing vascular cell adhesion molecule-1 expression in endothelial cells (EC), and global P2Y2R deficiency prevents fatty streak formation in apolipoprotein E null (ApoE-/-) mice. Because P2Y2R is ubiquitously expressed in vascular cells, we investigated the contribution of endothelial P2Y2R in the pathogenesis of atherosclerosis. APPROACH AND RESULTS: EC-specific P2Y2R-deficient mice were generated by breeding VEcadherin5-Cre mice with the P2Y2R floxed mice. Endothelial P2Y2R deficiency reduced endothelial nitric oxide synthase activity and significantly altered ATP- and UTP (uridine 5'-triphosphate)-induced vasorelaxation without affecting vasodilatory responses to acetylcholine. Telemetric blood pressure and echocardiography measurements indicated that EC-specific P2Y2R-deficient mice did not develop hypertension. We investigated the role of endothelial P2Y2R in the development of atherosclerotic lesions by crossing the EC-specific P2Y2R knockout mice onto an ApoE-/- background and evaluated lesion development after feeding a standard chow diet for 25 weeks. Histopathologic examination demonstrated reduced atherosclerotic lesions in the aortic sinus and entire aorta, decreased macrophage infiltration, and increased smooth muscle cell and collagen content, leading to the formation of a subendothelial fibrous cap in EC-specific P2Y2R-deficient ApoE-/- mice. Expression and proteolytic activity of matrix metalloproteinase-2 was significantly reduced in atherosclerotic lesions from EC-specific P2Y2R-deficient ApoE-/- mice. Furthermore, EC-specific P2Y2R deficiency inhibited nitric oxide production, leading to significant increase in smooth muscle cell migration out of aortic explants. CONCLUSIONS: EC-specific P2Y2R deficiency reduces atherosclerotic burden and promotes plaque stability in ApoE-/- mice through impaired macrophage infiltration acting together with reduced matrix metalloproteinase-2 activity and increased smooth muscle cell migration.

Direct Evidence for P2Y2 Receptor Involvement in Vascular Response to Injury.

OBJECTIVES: Extracellular nucleotide release at the site of arterial injury mediates the proliferation and migration of vascular smooth muscle cells. Our aim was to investigate the role of the P2Y2 nucleotide receptor (P2Y2R) in neointimal hyperplasia. Approach and Results: Vascular injury was induced by the implantation of a polyethylene cuff around the femoral artery in wild-type and P2Y2R-deficient mice (P2Y2R-/-). Electron microscopy was used to analyze monocyte and lymphocyte influx to the intima 36 h after injury. Compared to wild-type littermates, P2Y2R-/- mice exhibited a 3-fold decreased number of mononuclear leukocytes invading the intima (p < 0.05). Concomitantly, the migration of smooth muscle cells was decreased by more than 60% (p < 0.05), resulting in a sharp inhibition of intimal thickening formation in P2Y2R-/- mice (n = 15) 14 days after cuff placement. In vitro, loss of P2Y2R significantly impaired monocyte migration in response to nucleotide agonists. Furthermore, transgenic rats overexpressing the P2Y2R developed accelerated intimal lesions resulting in more than 95% luminal stenosis (p < 0.05, n = 10). CONCLUSIONS: Loss- and gain-of-function approaches established direct evidence for P2Y2R involvement in neointimal hyperplasia. Specific anti-P2Y2R therapies may be used against restenosis and bypass graft failure.

The P2Y2 receptor mediates uptake of matrix-retained and aggregated low density lipoprotein in primary vascular smooth muscle cells.

BACKGROUND AND AIMS: The internalization of aggregated low-density lipoproteins (agLDL) mediated by low-density lipoprotein receptor related protein (LRP1) may involve the actin cytoskeleton in ways that differ from the endocytosis of soluble LDL by the LDL receptor (LDLR). This study aims to define novel mechanisms of agLDL uptake through modulation of the actin cytoskeleton, to identify molecular targets involved in foam cell formation in vascular smooth muscle cells (VSMCs). The critical observation that formed the basis for these studies is that under pathophysiological conditions, nucleotide release from blood-derived and vascular cells activates SMC P2Y2 receptors (P2Y2Rs) leading to rearrangement of the actin cytoskeleton and cell motility. Therefore, we tested the hypothesis that P2Y2R activation mediates agLDL uptake by VSMCs. METHODS: Primary VSMCs were isolated from aortas of wild type (WT) C57BL/6 and.P2Y2R-/- mice to investigate whether P2Y2R activation modulates LRP1 expression. Cells were transiently transfected with cDNA encoding a hemagglutinin-tagged (HA-tagged) WT P2Y2R, or a mutant P2Y2R that unlike the WT P2Y2R does not bind the cytoskeletal actin-binding protein filamin-A (FLN-A). RESULTS: P2Y2R activation significantly increased agLDL uptake, and LRP1 mRNA expression decreased in P2Y2R-/- VSMCs versus WT. SMCs, expressing P2Y2R defective in FLN-A binding, exhibit 3-fold lower LDLR expression levels than SMCs expressing WT P2Y2R, while cells transfected with WT P2Y2R show greater agLDL uptake in both WT and P2Y2R-/- VSMCs versus cells transfected with the mutant P2Y2R. CONCLUSIONS: Together, these results show that both LRP1 and LDLR expression and agLDL uptake are regulated by P2Y2R in VSMCs, and that agLDL uptake due to P2Y2R activation is dependent upon cytoskeletal reorganization mediated by P2Y2R binding to FLN-A.

Deletion of P2Y2 receptor reveals a role for lymphotoxin-α in fatty streak formation.

BACKGROUND: Lymphotoxin alpha (LTα) is expressed in human atherosclerotic lesions and genetic variations in the LTα pathway have been linked to myocardial infarction. Activation of the P2Y2 nucleotide receptor (P2Y2R) regulates the production of LTα. in vitro. We aimed to uncover a potential pathway linking purinergic receptor to LTα-mediated inflammatory processes pivotal to the early stages of atherosclerosis in apolipoprotein E (ApoE(-)(/)(-)) deficient mice. METHODS AND RESULTS: En face immunostaining revealed that P2Y2R and VCAM-1 are preferentially expressed in the atherosclerosis prone site of the mouse aortic sinus. Deletion of the P2Y2R gene suppresses VCAM-1 expression. Compared with ApoE(-)(/)(-) mice, ApoE(-)(/)(-) mice lacking the P2Y2R gene (ApoE(-)(/)(-)/P2Y2R(-)(/)(-)) did not develop fatty streak lesions when fed a standard chow diet for 15weeks. Systemic and CD4(+) T cell production of the pro-inflammatory cytokine lymphotoxin-alpha (LTα) were specifically inhibited in ApoE(-)(/)(-)/P2Y2R(-)(/)(-)mice. Anti-LTα preventive treatment was initiated in ApoE(-)(/)(-)mice with intraperitoneal administration of recombinant human tumor necrosis factor receptor 1 fusion protein (TNFR1-Fc) on 5 consecutive days before the disease onset. Remarkably, none of the TNFR1:Fc-treated ApoE(-)(/)(-)mice exhibited atherosclerotic lesions at any developmental stage. SIGNIFICANCE: ApoE(-)(/)(-) mice deficient in P2Y2R exhibit low endothelial cell VCAM-1 levels, decreased production of LTα and delayed onset of atherosclerosis. These data suggest that targeting this nucleotide receptor could be an effective therapeutic approach in atherosclerosis.

P2Y receptors in the mammalian nervous system: pharmacology, ligands and therapeutic potential.

P2Y receptors for extracellular nucleotides are coupled to activation of a variety of G proteins and stimulate diverse intracellular signaling pathways that regulate functions of cell types that comprise the central nervous system (CNS). There are 8 different subtypes of P2Y receptor expressed in cells of the CNS that are activated by a select group of nucleotide agonists. Here, the agonist selectivity of these 8 P2Y receptor subtypes is reviewed with an emphasis on synthetic agonists with high potency and resistance to degradation by extracellular nucleotidases that have potential applications as therapeutic agents. In addition, the recent identification of a wide variety of subtype-selective antagonists is discussed, since these compounds are critical for discerning cellular responses mediated by activation of individual P2Y receptor subtypes. The functional expression of P2Y receptor subtypes in cells that comprise the CNS is also reviewed and the role of each subtype in the regulation of physiological and pathophysiological responses is considered. Other topics include the role of P2Y receptors in the regulation of blood-brain barrier integrity and potential interactions between different P2Y receptor subtypes that likely impact tissue responses to extracellular nucleotides in the CNS. Overall, current research suggests that P2Y receptors in the CNS regulate repair mechanisms that are triggered by tissue damage, inflammation and disease and thus P2Y receptors represent promising targets for the treatment of neurodegenerative diseases.

P2Y2 receptor-mediated lymphotoxin-α secretion regulates intercellular cell adhesion molecule-1 expression in vascular smooth muscle cells.

The proinflammatory cytokine lymphotoxin-α (LTA) is thought to contribute to the pathogenesis of atherosclerosis. However, the mechanisms that regulate its expression in vascular smooth muscle cells (VSMC) are poorly understood. The ability of exogenous nucleotides to stimulate LTA production was evaluated in VSMC by ELISA. The P2Y(2) nucleotide receptor (P2Y(2)R) agonist UTP stimulates a strong and sustained release of LTA from WT but not P2Y(2)R(-/-) SMC. Assessment of LTA gene transcription by LTA promoter-luciferase construct indicated that LTA levels are controlled at the level of transcription. We show using RNAi techniques that knockdown of the actin-binding protein filamin-A (FLNa) severely impaired nucleotide-induced Rho activation and consequent Rho-mediated LTA secretion. Reintroduction of FLNa in FLNa RNAi SMC rescued UTP-induced LTA expression. In addition, we found that UTP-stimulated LTA secretion is not sensitive to brefeldin A, which blocks the formation of vesicles involved in protein transport from the endoplasmic reticulum to the Golgi apparatus, suggesting that P2Y(2)R/filamin-mediated secretion of LTA is independent of the endoplasmic reticulum/Golgi secretory vesicle route. Furthermore, UTP selectively induces ICAM-1 expression in WT but not SMC expressing a truncated P2Y(2)R deficient in LTA secretion. These data suggest that P2Y(2)R recruits FLNa to provide a cytoskeletal scaffold necessary for Rho signaling pathway upstream of LTA release and subsequent stimulation of ICAM-1 expression on vascular smooth muscle cells.

P2Y2 nucleotide receptor-mediated responses in brain cells.

Acute inflammation is important for tissue repair; however, chronic inflammation contributes to neurodegeneration in Alzheimer's disease (AD) and occurs when glial cells undergo prolonged activation. In the brain, stress or damage causes the release of nucleotides and activation of the G(q) protein-coupled P2Y(2) nucleotide receptor subtype (P2Y(2)R) leading to pro-inflammatory responses that can protect neurons from injury, including the stimulation and recruitment of glial cells. P2Y(2)R activation induces the phosphorylation of the epidermal growth factor receptor (EGFR), a response dependent upon the presence of a SH3 binding domain in the intracellular C terminus of the P2Y(2)R that promotes Src binding and transactivation of EGFR, a pathway that regulates the proliferation of cortical astrocytes. Other studies indicate that P2Y(2)R activation increases astrocyte migration. P2Y(2)R activation by UTP increases the expression in astrocytes of alpha(V)beta(3/5) integrins that bind directly to the P2Y(2)R via an Arg-Gly-Asp (RGD) motif in the first extracellular loop of the P2Y(2)R, an interaction required for G(o) and G(12) protein-dependent astrocyte migration. In rat primary cortical neurons (rPCNs) P2Y(2)R expression is increased by stimulation with interleukin-1beta (IL-1beta), a pro-inflammatory cytokine whose levels are elevated in AD, in part due to nucleotide-stimulated release from glial cells. Other results indicate that oligomeric beta-amyloid peptide (Abeta(1-42)), a contributor to AD, increases nucleotide release from astrocytes, which would serve to activate upregulated P2Y(2)Rs in neurons. Data with rPCNs suggest that P2Y(2)R upregulation by IL-1beta and subsequent activation by UTP are neuroprotective, since this increases the non-amyloidogenic cleavage of amyloid precursor protein. Furthermore, activation of IL-1beta-upregulated P2Y(2)Rs in rPCNs increases the phosphorylation of cofilin, a cytoskeletal protein that stabilizes neurite outgrowths. Thus, activation of pro-inflammatory P2Y(2)Rs in glial cells can promote neuroprotective responses, suggesting that P2Y(2)Rs represent a novel pharmacological target in neurodegenerative and other pro-inflammatory diseases.

Rat parotid gland cell differentiation in three-dimensional culture.

The use of polarized salivary gland cell monolayers has contributed to our understanding of salivary gland physiology. However, these cell models are not representative of glandular epithelium in vivo, and, therefore, are not ideal for investigating salivary epithelial functions. The current study has developed a three-dimensional (3D) cell culture model for rat Par-C10 parotid gland cells that forms differentiated acinar-like spheres on Matrigel. These 3D Par-C10 acinar-like spheres display characteristics similar to differentiated acini in salivary glands, including cell polarization, tight junction (TJ) formation required to maintain transepithelial potential difference, basolateral expression of aquaporin-3 and Na+/K+/2Cl- cotransporter-1, and responsiveness to the muscarinic receptor agonist carbachol that is decreased by the anion channel blocker diphenylamine-2-carboxylic acid or chloride replacement with gluconate. Incubation of the spheres in the hypertonic medium increased the expression level of the water channel aquaporin-5. Further, the proinflammatory cytokines tumor necrosis factor-alpha and interferon-gamma induced alterations in TJ integrity in the acinar-like spheres without affecting individual cell viability, suggesting that cytokines may affect salivary gland function by altering TJ integrity. Thus, 3D Par-C10 acinar-like spheres represent a novel in vitro model to study physiological and pathophysiological functions of differentiated acini.