Atherosclerosis is a multifactorial disease that preferentially occurs in arterial regions exposed to d-flow can be used to indicate disturbed flow or disturbed blood flow. The mechanisms by which d-flow induces atherosclerosis involve changes in the transcriptome, methylome, proteome, and metabolome of multiple vascular cells, especially endothelial cells. Initially, we begin with the pathogenesis of atherosclerosis and the changes that occur at multiple levels owing to d-flow, especially in the endothelium. Also, there are a variety of strategies used for the global profiling of the genome, transcriptome, miRNA-ome, DNA methylome, and metabolome that are important to define the biological and pathophysiological mechanisms of endothelial dysfunction and atherosclerosis. Finally, systems biology can be used to integrate these ‘omics’ datasets, especially those that derive data based on a single animal model, in order to better understand the pathophysiology of atherosclerosis development in a holistic manner and how this integrative approach could be used to identify novel molecular diagnostics and therapeutic targets to prevent or treat atherosclerosis. WIREs Syst Biol Med 2016, 8:378–401. doi: 10.1002/wsbm.1344. For further resources related to this article, please visit the WIREs website.
by
Yanmei Zhao;
Wei Sun;
Pan Zhang;
Hao Chi;
Mei-Jun Zhang;
Chun-Qing Song;
Xuan Ma;
Yunlong Shang;
Bin Wang;
Youqiao Hu;
Zhiqi Hao;
Andreas F. Huehmer;
Fanxia Meng;
Steven L'Hernault;
Si-Min He;
Meng-Qiu Dong;
Long Miao
Spermiogenesis is a series of poorly understood morphological, physiological and biochemical processes that occur during the transition of immotile spermatids into motile, fertilization-competent spermatozoa. Here, we identified a Serpin (serine protease inhibitor) family protein (As-SRP-1) that is secreted from spermatids during nematode Ascaris suum spermiogenesis (also called sperm activation) and we showed that As-SRP-1 has two major functions. First, As-SRP-1 functions in cis to supportmajor spermprotein (MSP)- based cytoskeletal assembly in the spermatid that releases it, thereby facilitating sperm motility acquisition. Second, As-SRP-1 released froman activated sperminhibits, in trans, the activation of surrounding spermatids by inhibiting vas deferens-derived As-TRY-5, a trypsin- like serine protease necessary for sperm activation. Because vesicular exocytosis is necessary to create fertilization-competent sperm in many animal species, components released during this process might be more important modulators of the physiology and behavior of surrounding sperm than was previously appreciated.
Background: Urea, the end product of protein metabolism, has been considered to have negligible toxicity for a long time. Our previous study showed a depression phenotype in urea transporter (UT) B knockout mice, which suggests that abnormal urea metabolism may cause depression. The purpose of this study was to determine if urea accumulation in brain is a key factor causing depression using clinical data and animal models.
Methods: A meta-analysis was used to identify the relationship between depression and chronic diseases. Functional Magnetic Resonance Imaging (fMRI) brain scans and common biochemical indexes were compared between the patients and healthy controls. We used behavioural tests, electrophysiology, and molecular profiling techniques to investigate the functional role and molecular basis in mouse models.
Findings: After performing a meta-analysis, we targeted the relevance between chronic kidney disease (CKD) and depression. In a CKD mouse model and a patient cohort, depression was induced by impairing the medial prefrontal cortex. The enlarged cohort suggested that urea was responsible for depression. In mice, urea was sufficient to induce depression, interrupt long-term potentiation (LTP) and cause loss of synapses in several models. The mTORC1-S6K pathway inhibition was necessary for the effect of urea. Lastly, we identified that the hydrolysate of urea, cyanate, was also involved in this pathophysiology.
Interpretation: These data indicate that urea accumulation in brain is an independent factor causing depression, bypassing the psychosocial stress. Urea or cyanate carbamylates mTOR to inhibit the mTORC1-S6K dependent dendritic protein synthesis, inducing impairment of synaptic plasticity in mPFC and depression-like behaviour. CKD patients may be able to attenuate depression only by strict management of blood urea.
EP2 receptor has emerged as an important biological target for therapeutic intervention. In particular, it has been shown to exacerbate disease progression of a variety of CNS and peripheral diseases. Deletion of the EP2 receptor in mouse models recapitulates several features of the COX-2 inhibition, thus presenting a new avenue for anti-inflammatory therapy which could bypass some of the adverse side effects observed by the COX-2 inhibition therapy. We have recently reported a cinnamic amide class of EP2 antagonists with high potency, but these compounds exhibited a moderate selectivity against prostanoid receptor DP1. Moreover they possess acrylamide moiety in the structure, which may result in liver toxicity over longer period of use in a chronic disease model. Thus, we now developed a second generation compounds that devoid of the acrylamide functionality and possess high potency and improved (>1000-fold) selectivity to EP2 over other prostanoid receptors.
Progressive myoclonus epilepsies (PMEs) are disorders characterized by myoclonic and generalized seizures with progressive neurological deterioration. While several genetic causes for PMEs have been identified, the underlying causes remain unknown for a substantial portion of cases. Here we describe several affected individuals from a large, consanguineous family presenting with a novel PME in which symptoms begin in adolescence and result in death by early adulthood. Whole exome analyses revealed that affected individuals have a homozygous variant in GPR37L1 (c.1047G > T [Lys349Asn]), an orphan G protein-coupled receptor (GPCR) expressed predominantly in the brain. In vitro studies demonstrated that the K349N substitution in Gpr37L1 did not grossly alter receptor expression, surface trafficking or constitutive signaling in transfected cells. However, in vivo studies revealed that a complete loss of Gpr37L1 function in mice results in increased seizure susceptibility. Mice lacking the related receptor Gpr37 also exhibited an increase in seizure susceptibility, while genetic deletion of both receptors resulted in an even more dramatic increase in vulnerability to seizures. These findings provide evidence linking GPR37L1 and GPR37 to seizure etiology and demonstrate an association between a GPR37L1 variant and a novel progressive myoclonus epilepsy.
Rift Valley fever virus (RVFV) causes outbreaks of severe disease in people and livestock throughout Africa and the Arabian Peninsula. Human RVFV infections generally manifest as a self-limiting febrile illness, but in some individuals, the disease can progress to a fatal encephalitis or hemorrhagic syndrome. Little is known about the host characteristics that predispose development of more severe disease. Early in infection, interferon-mediated antiviral responses are critical for controlling RVFV replication, but the roles of downstream adaptive immune responses in determining clinical outcome have not been examined. Here, using a C57BL/6 mouse disease model, we evaluated the roles of B cells and T cells in RVFV pathogenesis. Given the profound inhibition of the innate response by the viral NSs protein and rapid course of wild-type infection, we utilized an attenuated RVFV lacking NSs to examine host responses following primary infection. Experiments utilizing B-cell-deficient mice or targeted T cell depletions of wild-type mice demonstrated that B cells and CD4 + T cells, but not CD8 + T cells, were critical for mediating viral clearance, even in the presence of a functional innate response. One-third of CD4 + -depleted mice developed severe neurologic disease following infection, in contrast to virus-infected mock-depleted mice that showed no clinical signs. CD4 + T cells were required for robust IgG and neutralizing antibody responses that correlated with RVFV clearance from peripheral tissues. Furthermore, CD4 + -depleted mice demonstrated significantly stronger proinflammatory responses relative to controls, suggesting CD4 + T cells regulate immune responses to RVFV infection. Together, these results indicate CD4 + T cells are critical determinants of RVFV pathogenesis and play an important role in preventing onset of neurologic disease.
Two urea transporters, UT-A1 and UT-A3, are expressed in the kidney terminal inner medullary collecting duct (IMCD) and are important for the production of concentrated urine. UT-A1, as the largest isoform of all UT-A urea transporters, has gained much attention and been extensively studied; however, the role and the regulation of UT-A3 are less explored. In this study, we investigated UT-A3 regulation by glycosylation modification. A site-directed mutagenesis verified a single glycosylation site in UT-A3 at Asn279. Loss of the glycosylation reduced forskolin-stimulated UT-A3 cell membrane expression and urea transport activity. UT-A3 has two glycosylation forms, 45 and 65 kDa. Using sugar-specific binding lectins, the UT-A3 glycosylation profile was examined. The 45-kDa form was pulled down by lectin concanavalin A (Con A) and Galant husnivalis lectin (GNL), indicating an immature glycan with a high amount of mannose (Man), whereas the 65-kDa form is a mature glycan composed of acetylglucosamine (GlcNAc) and poly-N-acetyllactosame (poly-LacNAc) that was pulled down by wheat germ agglutinin (WGA) and tomato lectin, respectively. Interestingly, the mature form of UT-A3 glycan contains significant amounts of sialic acid. We explored the enzymes responsible for directing UT-A3 sialylation. Sialyltransferase ST6GalI, but not ST3GalIV, catabolizes UT-A3 α2,6-sialylation. Activation of protein kinase C (PKC) by PDB treatment promoted UT-A3 glycan sialylation and membrane surface expression. The PKC inhibitor chelerythrine blocks ST6GalI-induced UT-A3 sialylation. Increased sialylation by ST6GalI increased UT-A3 protein stability and urea transport activity. Collectively, our study reveals a novel mechanism of UT-A3 regulation by ST6GalI-mediated sialylation modification that may play an important role in kidney urea reabsorption and the urinary concentrating mechanism.
Astrocytes are relatively resistant to injury compared to neurons and oligodendrocytes. Here, we report transient region-specific loss of astrocytes in mice early after pilocarpine-induced status epilepticus (SE). In the dentate hilus, immunoreactivity for glial acidic fibrillary protein (GFAP) was decreased, and the number of healthy appearing GFAP- or S100β-positive cells was significantly reduced (≥ 65%) 1 and 3 days after pilocarpine-induced SE. Many remaining GFAP-positive cells were shrunken, and 1 day after SE electron microscopy revealed numerous electron-dense degenerating astrocyte processes and degenerating glial somata in the hilus. Degeneration of GFAP-expressing cells may be linked to hilar neuronal death, because we did not observe loss of astrocytes after kainate-induced SE, after which hilar neurons remained intact. Ten days after SE, hilar GFAP immunoreactivity had returned, partially from GFAP-positive cells in the hilus. Unlike control mice, many GFAP-positive hilar processes originated from cell bodies located in the subgranular zone (SGZ). To investigate whether proliferation contributes to hilar repopulation, we injected 5-bromo-2′-deoxyuridine (BrdU) 3 days after SE. Five hours later and up to 31 days after SE, many BrdU/GFAP colabeled cells were found in the hilus and the SGZ, some with hilar processes, indicating that proliferation in both areas contributes to generation of hilar astrocytes and astrocyte processes. In contrast to pilocarpine-induced SE in mice, astrocyte degeneration was not found after pilocarpine-induced SE in rats. These findings demonstrate astrocyte degeneration in the mouse dentate hilus specifically in the mouse pilocarpine epilepsy model, followed by astrogenesis leading to hilar repopulation.
Desmosomes are cadherin-based adhesion structures that mechanically couple the intermediate filament cytoskeleton of adjacent cells to confer mechanical stress resistance to tissues. We have recently described desmosomes as mesoscale lipid raft membrane domains that depend on raft dynamics for assembly, function, and disassembly. Lipid raft microdomains are regions of the plasma membrane enriched in sphingolipids and cholesterol. These domains participate in membrane domain heterogeneity, signaling and membrane trafficking. Cellular structures known to be dependent on raft dynamics include the post-synaptic density in neurons, the immunological synapse, and intercellular junctions, including desmosomes. In this review, we discuss the current state of the desmosome field and put forward new hypotheses for the role of lipid rafts in desmosome adhesion, signaling and epidermal homeostasis. Furthermore, we propose that differential lipid raft affinity of intercellular junction proteins is a central driving force in the organization of the epithelial apical junctional complex.
by
Gary Miller;
Rong Fu;
LM Vecchio;
P Sullivan;
AR Dunn;
MK Bermejo;
ST Masoud;
E Gregersen;
NM Urs;
R Nazari;
PH Jensen;
A Ramsey;
DS Goldstein;
A Salahpour
In Parkinson's disease, dopamine-containing nigrostriatal neurons undergo profound degeneration. Tyrosine hydroxylase (TH) is the rate-limiting enzyme in dopamine biosynthesis. TH increases in vitro formation of reactive oxygen species, and previous animal studies have reported links between cytosolic dopamine build-up and oxidative stress. To examine effects of increased TH activity in catecholaminergic neurons in vivo, we generated TH-over-expressing mice (TH-HI) using a BAC-transgenic approach that results in over-expression of TH with endogenous patterns of expression. The transgenic mice were characterized by western blot, qPCR, and immunohistochemistry. Tissue contents of dopamine, its metabolites, and markers of oxidative stress were evaluated. TH-HI mice had a 3-fold increase in total and phosphorylated TH levels and an increased rate of dopamine synthesis. Coincident with elevated dopamine turnover, TH-HI mice showed increased striatal production of H2O2 and reduced glutathione levels. In addition, TH-HI mice had elevated striatal levels of the neurotoxic dopamine metabolites 3,4-dihydroxyphenylacetaldehyde and 5-S-cysteinyl-dopamine and were more susceptible than wild-type mice to the effects of amphetamine and methamphetamine. These results demonstrate that increased TH alone is sufficient to produce oxidative stress in vivo, build up autotoxic dopamine metabolites, and augment toxicity. (Figure presented.).