Neurotransmitter and their metabolite concentrations in different areas of the HPRT knockout mouse brain

Simultaneous enrichment and sequential elution of cis-diol containing molecules and deoxyribonucleotides with bifunctional boronate and titanium (Ⅳ) ion modified-magnetic nanoparticles prior to quantitation by high performance liquid chromatography

Some diseases can cause abnormal concentrations of catecholamines (CAs), nucleosides (NSs) and nucleotides (NTs) in patients. Previous studies normally focused on the detection of the three types of substances separately. In this work, a bifunctional boronate and titanium (Ⅳ) ion affinity magnetic adsorbent with high-capacity was prepared. The adsorbent can simultaneously enrich CAs, NSs and NTs in a single extraction process, and the adsorbed analytes can be sequentially eluted by 1.0% trifluoroacetic acid and 20.0 mmol L-1 Na3PO4. An analytical method of the analytes has been established by coupling the adsorbent with RP-HPLC. The method has low detection limits (0.039-0.708 ng mL-1) and good reproducibility (inter- and intra-day of assay RSDs less than 15.0%). Serum sample from healthy volunteer was successfully quantified for two CAs, four NSs and five NTs. Compared with the reported methods, the proposed method is simpler to operate, consume less samples, and has enough accurate and sensitivity to obtain comprehensive information on the concentrations of analytes in a single extraction process.

Sympathetic nerve infiltration promotes stomach adenocarcinoma progression via norepinephrine/β2-adrenoceptor/YKL-40 signaling pathway

Objective

This study aimed to address the status, role, and mechanism of sympathetic nerve infiltration in the progression of stomach adenocarcinoma (STAD).

Methods

Sympathetic nerve and its neurotransmitter NE, β-ARs, and associated signaling molecules in the STAD tissues and the adjacent tissues from 46 STAD patients were examined using immunostaining, HPLC, and western blotting. The effects and mechanisms of β2-AR activation on the proliferation, migration and invasion of AGS and SGC-7901 gastric cancer (GC) cell lines were examined using CCK-8, transwell, and western blotting assays. Correlations between genes and STAD survival were analyzed using bioinformatics.

Results

Striking sympathetic nerve infiltration, elevations of NGF, TrkA, GAP43, TH, S100, NE, β2-AR, YKL-40, syndecan-1, MMP9, CD206, and CD31 were observed in the STAD tissues compared to the adjacent tissues. Activation of β2-AR in the two GC cell lines significantly amplified the expressions of NGF, YKL-40, MMP9, syndecan-1, p-STAT3 and p-ERK, and increased GC cell proliferation, migration and invasion. Bioinformatic analyses revealed positive correlations of NGF, β2-AR, syndecan-1, and macrophage infiltration, respectively, with low survival of STAD, of β2-AR respectively with STAT3, ERK1/2 (MAPK1/3), YKL-40, MMP9, and syndecan-1, and of YKL-40 with MMP9.

Conclusion

Sympathetic nerves significantly infiltrated into human STAD tissues as a result of high NGF and TrkA expressions; elevated NE led to overactivation of β2-AR-STAT3/ERK-YKL-40 signaling pathway, and finally caused cancer cell growth and invasion, M2 macrophage infiltration, angiogenesis, matrix degradation and STAD metastasis and progression.

Type 2 diabetic mice enter a state of spontaneous hibernation-like suspended animation following accumulation of uric acid

Hibernation is an example of extreme hypometabolic behavior. How mammals achieve such a state of suspended animation remains unclear. Here we show that several strains of type 2 diabetic mice spontaneously enter into hibernation-like suspended animation (HLSA) in cold temperatures. Nondiabetic mice injected with ATP mimic the severe hypothermia analogous to that observed in diabetic mice. We identified that uric acid, an ATP metabolite, is a key molecular in the entry of HLSA. Uric acid binds to the Na⁺ binding pocket of the Na⁺/H⁺ exchanger protein and inhibits its activity, acidifying the cytoplasm and triggering a drop in metabolic rate. The suppression of uric acid biosynthesis blocks the occurrence of HLSA, and hyperuricemic mice induced by treatment with an uricase inhibitor can spontaneously enter into HLSA similar to that observed in type 2 diabetic mice. In rats and dogs, injection of ATP induces a reversible state of HLSA similar to that seen in mice. However, ATP injection fails to induce HLSA in pigs due to the lack of their ability to accumulate uric acid. Our results raise the possibility that nonhibernating mammals could spontaneously undergo HLSA upon accumulation of ATP metabolite, uric acid.

Characterization of monoaminergic neurochemicals in the different brain regions of adult zebrafish

Monoaminergic neurotransmitters are the main components that regulate of a lot of processes in the vertebrate brain. There is growing interest to monitor the changes produced in these neurochemicals due to the large number of exogenous agents, such as pharmaceuticals and drugs of abuse, targeting and affecting this system. Adult zebrafish (Danio rerio) shares the common neurotransmitter pathways and nervous system organization with mammals. Therefore, a method based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) has been developed for the first time to study the profile of ten monoaminergic neurochemicals in the anterior, middle and posterior brain regions of adult zebrafish. Moreover, the applied LC-MS/MS method has been studied in terms of quality such as linearity, sensitivity and intra- and inter-day precision. The analytical method based in LC-MS/MS has become a new source in neurotoxicology using adult zebrafish as research model. Significant differences on the levels of these neurotransmitters have been found between the different brain regions. CAPSULE: The profile of ten monoaminergic neurochemicals in the main three brain areas of adult zebrafish has been reported for the first time in this manuscript.

Rescuing compounds for Lesch-Nyhan disease identified using stem cell-based phenotypic screening

Lesch-Nyhan disease (LND) is a rare monogenic disease caused by deficiency of the salvage pathway enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). LND is characterized by severe neuropsychiatric symptoms that currently cannot be treated. Predictive in vivo models are lacking for screening and evaluating candidate drugs because LND-associated neurological symptoms are not recapitulated in HGPRT-deficient animals. Here, we used human neural stem cells and neurons derived from induced pluripotent stem cells (iPSCs) of children affected with LND to identify neural phenotypes of interest associated with HGPRT deficiency to develop a target-agnostic-based drug screening system. We screened more than 3000 molecules and identified 6 pharmacological compounds, all possessing an adenosine moiety, that corrected HGPRT deficiency-associated neuronal phenotypes by promoting metabolism compensations in an HGPRT-independent manner. This included S-adenosylmethionine, a compound that had already been used as a compassionate approach to ease the neuropsychiatric symptoms in LND. Interestingly, these compounds compensate abnormal metabolism in a manner complementary to the gold standard allopurinol and can be provided to patients with LND via simple food supplementation. This experimental paradigm can be easily adapted to other metabolic disorders affecting normal brain development and functioning in the absence of a relevant animal model.

What Gene Mutations Affect Serotonin in Mice?

Although serotonin neurotransmission has been implicated in several neurodevelopmental and psychological disorders, the factors that drive dysfunction of the serotonin system are poorly understood. Current research regarding the serotonin system revolves around its dysfunction in neuropsychiatric disorders, but there is no database collating genetic mutations that result in serotonin abnormalities. To bridge this gap, we developed a list of genes in mice that, when perturbed, result in altered levels of serotonin either in brain or blood. Due to the intrinsic limitations of search, the current list should be considered a preliminary subset of all relevant cases. Nevertheless, it offered an opportunity to gain insight into what types of genes have the potential to impact serotonin by using gene ontology (GO). This analysis found that genes associated with monoamine metabolism were more often associated with increases in brain serotonin than decreases. Speculatively, this could be because several pathways (and therefore many genes) are responsible for the clearance and metabolism of serotonin whereas only one pathway (and therefore fewer genes) is directly involved in the synthesis of serotonin. Another contributor could be cross talk between monoamine systems such as dopamine. In contrast, genes that were associated with decreases in brain serotonin were more likely linked to a developmental process. Sensitivity of serotonin neurons to developmental perturbations could be due to their complicated neuroanatomy or possibly they may be negatively regulated by dysfunction of their innervation targets. Thus, these observations suggest hypotheses regarding the mechanisms underlying the vulnerability of brain serotonin neurotransmission.

Analytical Methods for the Quantification of Histamine and Histamine Metabolites

The endogenous metabolite histamine (HA) is synthesized in various mammalian cells but can also be ingested from exogenous sources. It is involved in a plethora of physiological and pathophysiological processes. So far, four different HA receptors (H₁R-H₄R) have been described and numerous HAR antagonists have been developed. Contemporary investigations regarding the various roles of HA and its main metabolites have been hampered by the lack of highly specific and sensitive analytic methods for all of these analytes. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is the method of choice for identification and sensitive quantification of many low-molecular weight endogenous metabolites. In this chapter, different methodological aspects of HA quantification as well as recommendations for LC-MS/MS methods suitable for analysis of HA and its main metabolites are summarized.