Dopa Decarboxylase Expression Research Articles

Computer-aided design and implementation of efficient biosynthetic pathways to produce high added-value products derived from tyrosine in Escherichia coli.

Developing efficient bioprocesses requires selecting the best biosynthetic pathways, which can be challenging and time-consuming due to the vast amount of data available in databases and literature. The extension of the shikimate pathway for the biosynthesis of commercially attractive molecules often involves promiscuous enzymes or lacks well-established routes. To address these challenges, we developed a computational workflow integrating enumeration/retrosynthesis algorithms, a toolbox for pathway analysis, enzyme selection tools, and a gene discovery pipeline, supported by manual curation and literature review. Our focus has been on implementing biosynthetic pathways for tyrosine-derived compounds, specifically L-3,4-dihydroxyphenylalanine (L-DOPA) and dopamine, with significant applications in health and nutrition. We selected one pathway to produce L-DOPA and two different pathways for dopamine-one already described in the literature and a novel pathway. Our goal was either to identify the most suitable gene candidates for expression in Escherichia coli for the known pathways or to discover innovative pathways. Although not all implemented pathways resulted in the accumulation of target compounds, in our shake-flask experiments we achieved a maximum L-DOPA titer of 0.71g/L and dopamine titers of 0.29 and 0.21g/L for known and novel pathways, respectively. In the case of L-DOPA, we utilized, for the first time, a mutant version of tyrosinase from Ralstonia solanacearum. Production of dopamine via the known biosynthesis route was accomplished by coupling the L-DOPA pathway with the expression of DOPA decarboxylase from Pseudomonas putida, resulting in a unique biosynthetic pathway never reported in literature before. In the context of the novel pathway, dopamine was produced using tyramine as the intermediate compound. To achieve this, tyrosine was initially converted into tyramine by expressing TDC from Levilactobacillus brevis, which, in turn, was converted into dopamine through the action of the enzyme encoded by ppoMP from Mucuna pruriens. This marks the first time that an alternative biosynthetic pathway for dopamine has been validated in microbes. These findings underscore the effectiveness of our computational workflow in facilitating pathway enumeration and selection, offering the potential to uncover novel biosynthetic routes, thus paving the way for other target compounds of biotechnological interest.

Baitouweng decoction alleviates ulcerative colitis by regulating tryptophan metabolism through DOPA decarboxylase promotion.

Baitouweng decoction (BTW) is a classic botanical drugs formula that has been widely used clinically for the treatment of gut-related disorders in China. However, its role in ameliorating ulcerative colitis (UC) remains to be explored. The study aimed to determine the therapeutic efficacy and potential mechanism of action of BTW on dextran sodium sulfate (DSS)-induced colitis mice. In vivo: 3.5% DSS-induced experimental colitis mice were treated with BTW (Pulsatilla chinensis (Bunge) Regel, Phellodendron chinense C. K. Schneid, Coptis chinensis Franch and Fraxinus chinensis Roxb), kynurenine or DOPA decarboxylase (DDC) inhibitor (carbidopa). In vitro: Caco-2 cells were stimulated with TNF-α to activate inflammation and later treated with various concentrations of BTW and carbidopa. Model evaluation included body weight, disease activity index (DAI) score, colon length and histopathology. Cytokine levels were measured by flow cytometry. Protein levels were analyzed by proteomics and functionally annotated. The levels of tryptophan metabolites in mouse serum and colon were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Alcian Blue/Phosphate Acid Schiff (AB/PAS) staining, immunohistochemistry and western blot were used to assess the intestinal barrier function and detect the protein expression levels. BTW significantly reduced the DAI, ameliorated colonic injury and regulated inflammatory cytokines in DSS-induced colitis mice. The botanical drugs formula also promoted intestinal epithelial barrier repair by enhancing the expression of the tight junction (TJ) proteins. Tryptophan metabolic signaling pathway was significantly enriched in DSS-induced UC mice, and BTW decreased the level of kynurenine, increased indole metabolites. The therapeutic effect of BTW was evidently reduced when kynurenine was given to mice. Also, BTW promoted DDC protein expression and activated the aryl hydrocarbon receptor (AHR)/IL-22 signaling pathway. BTW improves ulcerative colitis by promoting DDC expression, regulating the conversion of tryptophan metabolism from the kynurenine pathway to the indole metabolism pathway, thereby modulating tryptophan metabolism to increase indole metabolites, and activating AHR receptors to restore intestinal barrier function.

Comparing the effect of intravenous versus intracranial grafting of mesenchymal stem cells against parkinsonism in a rat model: Behavioral, biochemical, pathological and immunohistochemical studies.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases worldwide. Currently applied therapeutic protocols are limited to improve the motor functions of patients. Therefore, seeking alternative regimes with better therapeutic impact is crucial. This study aims to validate the therapeutic impact of mesenchymal stem cell injection using two delivery methods, intracranial administration and intravenous administration, on rotenone (ROT)-induced PD model in rats. Our work included behavioral, biochemical, histological, and molecular investigations. Open field test (OFT) and rotarod tests were applied. Important oxidative stress, antioxidant and proinflammatory markers were monitored. Substantia Nigra and Striatum tissues were examined histologically and the molecular expression of DOPA decarboxylase, Tyrosine hydroxylase, and α-synuclein in neurons in these tissues were investigated. Our results showed that MSC grafting improved motor and memory impairments and oxidative stress status that were observed after ROT administration. Additionally, BM-MSCs application restored SOD and CAT activities and the levels of DA, L-Dopa, IL6, IL1β, and TNFα. Moreover, MSC grafting overwhelmed the pathological changes induced by ROT and normalized the expression of Tyrosine hydroxylase, DOPA decarboxylase, and α-synuclein towards the control values in the Nigral and Striatal tissues of male rats. Conclusively, both administration routes improved motor function, protection of the nigrostriatal system, and improved striatal dopamine release. The observed beneficial effect of applying MSCs suggests potential benefits in clinical applications. No significant differences in the outcomes of the treatment would favor a certain way of MSC application over the other. However, the intravenous delivery method seems to be safer and more feasible compared to the intrastriatal method.

Neuroprotective Effects of Zinc Oxide Nanoparticles in a Rotenone-Induced Mouse Model of Parkinson's Disease.

Goals of the investigation: This work aimed to evaluate the neuroprotective effects of zinc oxide (ZnO) nanoparticles in an experimental mouse model of rotenone-induced PD and investigate the therapeutic effects of ZnO, cobalt ferrite nanoparticles, and their combination. Methods: The levels of dopamine, norepinephrine, epinephrine, and serotonin were assessed using ELISA in the control and experimental model of PD mice. The dopa-decarboxylase expression level was assayed by real-time PCR. The expression level of tyrosine hydroxylase (TH) was assessed by western blot analysis. Results: Our data showed that levels of dopamine decreased in PD mice compared to normal. ZnO NP increased dopamine levels in normal and PD mice (37.5% and 29.5%; respectively, compared to untreated mice). However, ZnO NP did not cause any change in norepinephrine and epinephrine levels either in normal or in PD mice. Levels of serotonin decreased by 64.0%, and 51.1% in PD mice treated with cobalt ferrite and dual ZnO- cobalt ferrite NPs; respectively, when compared to PD untreated mice. The mRNA levels of dopa-decarboxylase increased in both normal and PD mice treated with ZnO NP. Its level decreased when using cobalt ferrite NP and the dual ZnO-cobalt ferrite NP when compared to untreated PD mice. A significant decrease in TH expression by 0.25, 0.68, and 0.62 folds was observed in normal mice treated with ZnO, cobalt ferrite, and the dual ZnO-cobalt ferrite NP as compared to normal untreated mice. In PD mice, ZnO administration caused a non-significant 0.15-fold decrease in TH levels while both cobalt ferrite and the dual ZnO-cobalt ferrite NP administration caused a significant 0.3 and 0.4-fold decrease respectively when compared to untreated PD mice. Principal conclusion: This study reveals that ZnO NPs may be utilized as a potential intervention to elevate dopamine levels to aid in PD treatment.

Neuroprotective Effect of Curcumin on the Rat Model of Parkinson’s Disease Induced by Rotenone via Modulating Tyrosine Hydroxylase and Dopa Decarboxylase Expression Levels

Neuroprotective Effect of Curcumin on the Rat Model of Parkinson’s Disease Induced by Rotenone via Modulating Tyrosine Hydroxylase and Dopa Decarboxylase Expression Levels

DDC-Promoter-Driven Chemogenetic Activation of SNpc Dopaminergic Neurons Alleviates Parkinsonian Motor Symptoms.

Parkinson's disease (PD) is a neurodegenerative disorder with typical motor symptoms. Recent studies have suggested that excessive GABA from reactive astrocytes tonically inhibits dopaminergic neurons and reduces the expression of tyrosine hydroxylase (TH), the key dopamine-synthesizing enzyme, in the substantia nigra pars compacta (SNpc). However, the expression of DOPA decarboxylase (DDC), another dopamine-synthesizing enzyme, is relatively spared, raising a possibility that the live but non-functional TH-negative/DDC-positive neurons could be the therapeutic target for rescuing PD motor symptoms. However, due to the absence of a validated DDC-specific promoter, manipulating DDC-positive neuronal activity has not been tested as a therapeutic strategy for PD. Here, we developed an AAV vector expressing mCherry under rat DDC promoter (AAV-rDDC-mCherry) and validated the specificity in the rat SNpc. Modifying this vector, we expressed hM3Dq (Gq-DREADD) under DDC promoter in the SNpc and ex vivo electrophysiologically validated the functionality. In the A53T-mutated alpha-synuclein overexpression model of PD, the chemogenetic activation of DDC-positive neurons in the SNpc significantly alleviated the parkinsonian motor symptoms and rescued the nigrostriatal TH expression. Altogether, our DDC-promoter will allow dopaminergic neuron-specific gene delivery in rodents. Furthermore, we propose that the activation of dormant dopaminergic neurons could be a potential therapeutic strategy for PD.

A region-dependent allele-biased expression of Dopa decarboxylase in mouse brain.

Genomic imprinting is an epigenetic event in which genes are expressed only from either the paternal or maternal allele. Dopa decarboxylase (Ddc), is an imprinted gene that encodes an enzyme which catalyzes the conversion of L-dopa to dopamine. Although Ddc has been reported to be paternally expressed in embryonic and neonatal hearts, its expression pattern in the brain has been controversial. To visualize Ddc-expressing neurons, we established a knock-in mouse carrying a humanized Kusabira orange 1 (hKO1) reporter cassette at the Ddc locus (Ddc-hKO1). The expression of Ddc-hKO1 was detected in all known Ddc-positive cells in the brains of embryonic, neonatal, adult, and aged mice. We further developed an efficient purification method for Ddc-hKO1-positive neurons using a cell sorter. RNA sequencing analysis confirmed the enrichment of dopaminergic, serotonergic and cholinergic neurons in Ddc-hKO1-positive cell population recovered using this method. A detailed analysis of Ddc-hKO1 paternally and maternally derived heterozygous mice combined with immunostaining revealed that Ddc was preferentially expressed from the maternal allele in ventral tegmented area (VTA), substantia nigra pars compacta (SNc), and retrorubral field (RRF); while it was expressed from both alleles in dorsal raphe nucleus (DR). These results indicate that Ddc exhibit an allele-specific expression pattern in different brain regions, presumably reflecting the diverse regulatory mechanisms of imprinting.

P16-16 Mitochondrial respiratory chain inhibitor pesticides alter expression of dopa decarboxylase and growth differentiation factor 15 in SH-SY5Y neurons

P16-16 Mitochondrial respiratory chain inhibitor pesticides alter expression of dopa decarboxylase and growth differentiation factor 15 in SH-SY5Y neurons

Extensive cross-talk among stress-regulated protective metabolites, biogenic-amines and phytohormone-signalling, co-ordinated by dopamine-mediated seed-priming, governs tolerance against fluoride stress in rice.

Seed priming with dopamine reduced fluoride bioaccumulation, induced endogenous dopamine level, thereby orchestrating phytohormone homeostasis and biogenic amine metabolism, and modulating osmolyte and antioxidant machinery to enhance fluoride tolerance in rice. The aim of this study was to decipher the efficacy of seed priming with dopamine in curtailing the adverse impacts of fluoride toxicity in rice seedlings. Fluoride-stressed seedlings exhibited severe growth retardation, high fluoride bioaccumulation, electrolyte leakage and marked cellular injuries. Dopamine priming stimulated the overall physiological growth parameters during stress, via reduced formation of H2O2, malondialdehyde and methylglyoxal, due to lesser fluoride-accumulation. Fluoride stress-induced endogenous dopamine level was further induced upon dopamine priming, marked by the up regulated DOPA decarboxylase expression. Additionally, dopamine treatment led to escalated activity of catalase, superoxide dismutase and glutathione peroxidase in the stressed seedlings, concomitant with altered CAT, SOD and GPX expression. The higher accumulation of protective osmolytes (proline and total amino acids) and non-enzymatic antioxidants (phenolics, flavonoids, anthocyanins, glutathione and carotenoids), upon dopamine priming, during fluoride stress, could be linked with the altered expression pattern of the respective genes. Dopamine promoted active utilization of the biogenic amine (polyamines and ϒ-amino butyric acid) pools for toxicity mitigation, correlated with the modulation of the concerned enzyme activity and gene expression. Dopamine stimulated the accumulation of phytohormones like gibberellin and salicylic acid, via inducing the biosynthetic genes like gibberellin-3-oxidase (GA3ox) and isochorismate synthase (ICS), respectively, while depreciating the abscisic acid and melatonin level during fluoride stress. To our knowledge, this is the first documented report for the remedial role of dopamine priming against fluoride stress in any plant species. This study will open new arenas in sustainable agriculture for the exploitation of this pulsating biomolecule against fluoride stress.

Metabonomic and transcriptomic analyses of Tripterygium glycosides tablet-induced hepatotoxicity in rats

We aimed to explore novel biomarkers involved in alterations of metabolism and gene expression related to the hepatotoxic effects of Tripterygium glycosides tablet (TGT) in rats. Rats were randomly divided into groups based on oral administration of TGTs for 6 weeks: control, low-dose (9.5 mg/kg), and high-dose (18.9 mg/kg). Serum samples and total liver RNA were subjected to metabonomic and transcriptomic analyses. Thirteen metabolites were significantly up-regulated by liver injury induced by Tripterygium glycosides. Five potential biomarkers were more sensitive than Alanine aminotransferase (ALT) for accurate and timely prediction of hepatic damage. The four metabolic pathways most obviously regulated by hepatotoxicity were D-glutamine and D-glutamate metabolism, alanine, aspartate and glutamate metabolism, ether lipid metabolism, and tryptophan metabolism. Transcriptomics revealed significant differences in 1792 mRNAs and 400 long non-coding (lnc) RNAs. Dysregulated lncRNAs in the TGT-induced hepatotoxicity group were associated with genes involved in amino acid metabolism using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. Up-regulated expression of Ehhadh, Gpt, and Got1, and down-regulated expression of dopa decarboxylase (Ddc), Cyp1a2, Ido2, Aldh1b1, and asparagine synthetase (Asns) was validated by quantitative real-time PCR. This multiomics study has elucidated the relationship between amino metabolism and liver injury, revealing potential biomarkers.

Tyrosine Hydroxylase and DOPA Decarboxylase Are Associated With Pupal Melanization During Larval-Pupal Transformation in Antheraea pernyi.

In insects, melanism plays important roles in defense, immunoreactions, and body color. The underlying molecular mechanisms of melanism in different insects are diverse and remain elusive. In contrast to another silkworm, Bombyx mori, the Chinese oak silkworm, Antheraea pernyi, produces melanic pupae under natural environmental conditions. DOPA and dopamine synthesis are crucial for melanin formation. Disruption of these processes reportedly influences body colors in many insects. Most research focuses on newly emerged pupae, and the larval process preceding pupation remains unknown. Due to the large size and long pupation period in A. pernyi, the entire process was studied at least every 12 h. The expression patterns of tyrosine hydroxylase (TH) and DOPA decarboxylase (DDC), which are involved in DOPA and dopamine synthesis in the epidermis, were evaluated during larval–pupal metamorphosis. We also performed RNA interference (RNAi) and used enzyme inhibitors to examine morphological changes. The amino acid sequences of TH and DDC share 90.91% and 86.64% identity with those of B. mori. TH and DDC expression was upregulated during the 48–72 h period prior to pupal emergence, especially at 60 h. RNAi of TH and DDC induced partial melanism in some pupae. The inhibitors 3-iodo-tyrosine (3-IT) and L-α-methyl-DOPA (L-DOPA) influenced pupal melanization. Different concentrations of inhibitors led to pupal deformity and even mortality. Four different monoamines, only DOPA and Dopamine synthezed from Tyrosine will be influenced by TH and DDC inhibitor. These results indicate that TH and DDC are key genes associated with pupal melanization during larval–pupal transformation in A. pernyi. Overall, our results suggest that TH and DDC expression alterations in a particular stage can affect body color, setting the molecular basis for artificial control of pupal melanization.

Peroxiredoxin 6 Overexpression Induces Anxiolytic and Depression-Like Behaviors by Regulating the Serotonergic Pathway in Mice.

Peroxiredoxin 6 (PRDX6) is a bifunctional protein with both glutathione peroxidase and calcium-independent phospholipase activity. Recently, we reported that PRDX6 plays an important role in dopaminergic neurodegeneration in Parkinson’s disease. However, the relationship between PRDX6 function and emotional behavior remains elusive. In the present study, we examined depression- and anxiety-like behaviors in PRDX6-overexpressing transgenic (PRDX6-Tg) mice using the forced swim test, tail suspension test, open field paradigm, and elevated plus-maze. PRDX6-Tg mice exhibited depression-like behaviors and low anxiety. In particular, female PRDX6-Tg mice exhibited anxiolytic behavior in the open field test. Furthermore, the serotonin content in the cortex and 5-hydroxytryptophan-induced head twitch response were both reduced in PRDX6-Tg mice. Interestingly, levels of dopa decarboxylase expression in the cortex were decreased in male PRDX6-Tg mice but not in female mice. Our findings provide novel insights into the role of PRDX6 in 5-HT synthesis and suggest that PRDX6 overexpression can induce depression-like behaviors via downregulation of the serotonergic neuronal system.

Heterogeneous expression of DOPA decarboxylase to improve the production of dopamine in Escherichia coli

Dopamine is the precursor of a variety of natural antioxidant compounds. In the body, dopamine acts as a neurotransmitter that regulates a variety of physiological functions of the central nervous system. Thus, dopamine is used for the clinical treatment of various types of shock. Dopamine could be produced by engineered microbes, but with low efficiency. In this study, DOPA decarboxylase gene from Sus scrofa (Ssddc) was cloned into plasmids with different copy numbers, and transformed into a previously developed L-DOPA producing strain Escherichia coli T004. The resulted strain was capable of producing dopamine from glucose directly. To further improve the production of dopamine, a sequence-based homology alignment mining (SHAM) strategy was applied to screen more efficient DOPA decarboxylases, and five DOPA decarboxylase genes were selected from 100 candidates. In shake-flask fermentation, the DOPA decarboxylase gene from Homo sapiens (Hsddc) showed the highest dopamine production (3.33 g/L), while the DOPA decarboxylase gene from Drosophila Melanogaster (Dmddc) showed the least residual L-DOPA concentration (0.02 g/L). In 5 L fed-batch fermentations, production of dopamine by the two engineered strains reached 13.3 g/L and 16.2 g/L, respectively. The residual concentrations of L-DOPA were 0.45 g/L and 0.23 g/L, respectively. Finally, the Ssddc and Dmddc genes were integrated into the genome of E. coli T004 to obtain genetically stable dopamine-producing strains. In 5 L fed-batch fermentation, 17.7 g/L of dopamine was produced, which records the highest titer reported to date.

Dopamine Synthesis and D1 Receptor Agonism are Essential for Resolution of Experimental Lung Fibrosis

Rationale Idiopathic Pulmonary fibrosis (IPF) is characterized by progressive and ultimately fatal end-stage lung scarring associated with uncontrolled deposition, stiffening and remodeling of fibrous connective tissue proteins. We have previously shown that agonism of the dopamine receptor D1 attenuates experimental lung fibrosis in mice, and that the lungs of IPF patients display reduced transcript and protein levels of DOPA decarboxylase (DDC), the enzyme that catalyzes the biosynthesis of dopamine. Here we investigate the role of endogenous dopamine production and signaling in the resolution of experimental lung fibrosis. Methods Using a self-resolving model of experimental lung fibrosis, we administered bleomycin (1.1U/kg) to 10-week old mice intratracheally at day 0, and collected lung tissue from sham and bleo groups at day 21 to establish the level of baseline fibrosis. We then administered the DDC inhibitor carbidopa (20mg/kg, IP), the D1 receptor antagonist SCH 39166 (0.5mg/kg, SC), or vehicle control daily from day 21 to 42. Lung tissue was collected for hydroxyproline and histological analysis. In order to investigate dopamine synthesis and signaling ex vivo, we generated precision-cut lung slices (PCLS) from healthy mice and stimulated them +/- TGFβ for 72 hours and collected total RNA from the lung slices and conditioned media to measure dopamine production by ELISA. Results As previously observed, lung tissue collected at day 21 post injury displayed enhanced markers of fibrosis measured by hydroxyproline (478% increase over sham) and H&E stained histology. By day 42 the vehicle control mice resolved this fibrosis. In contrast, the mice treated with carbidopa or SCH 39166 maintained the fibrosis observed at day 21 (514% and 592% increase compared to sham, respectively). Consistent with our prior observation in IPF patient lung, PCLS cultured ex vivo with TGFβ expressed significantly less Ddc (75% reduction compared to control) and total dopamine abundance in the conditioned media dropped from ~120ng/mL to ~32ng/mL. Conclusions Dopamine synthesis through the activity of DDC, and agonism of the dopamine receptor D1 are essential to pulmonary fibrosis resolution after injury. PCLS represents a useful model to further investigate the molecular mechanisms leading to reduced expression of DDC, and test pharmacological approaches to stimulate dopamine signaling as a potential therapy for IPF.

MicroRNA-277 regulates dopa decarboxylase to control larval-pupal and pupal-adult metamorphosis of Helicoverpa armigera

Insect metamorphosis is a complex process involving many metabolic pathways, such as juvenile hormones and molting hormones, bioamines, microRNAs (miRNAs), etc. However, relatively little is known about the biogenic amines and their miRNAs to regulate cotton bollworm metamorphosis. Here we show that one miRNA, miR-277 regulates larval-pupal and pupal-adult metamorphosis of cotton bollworm by targeting the 3′UTR of Dopa decarboxylase (DDC), a synthetic catalytic enzyme of dopamine. Injection of miR-277 agomir inhibited the expression of DDC at the mRNA and protein levels, leading to defects in the pupation and emergence of H. armigera that was consistent with the phenotype obtained by injection of DDC double-stranded RNA (dsRNA). Injection of miR-277 antagomir induced the mRNA and protein expression of DDC and rescued the phenotype of pupation failure caused by DDC gene silencing. Unexpectedly, miR-277 antagomir can also cause failure of emergence of H. armigera and both agomir and antagomir of miR-277 injection could cause abnormal phenotypes in wing veins. This study reveals that elaborate regulation of miRNA and its target gene expression is prerequisite for insect development, which provides a new insight to study the developmental mechanisms of insect wing veins.

Exposure to atrazine alters behaviour and disrupts the dopaminergic system in Drosophila melanogaster

Atrazine is an extensively used herbicide, and has become a common environmental contaminant. Effects on dopaminergic neurotransmission in mammals following exposure to atrazine have been previously demonstrated. Here, the effects of atrazine regarding behavioural and dopaminergic neurotransmission parameters were assessed in the fruit fly D. melanogaster, exposed during embryonic and larval development. Embryos (newly fertilized eggs) were exposed to two atrazine concentrations (10μM and 100μM) in the diet until the adult fly emerged. Negative geotaxis assay, as well as exploratory behaviour, immobility time and number of grooming episodes in an open field system were assessed. Tyrosine hydroxylase (TH) activity and gene expression of the dopaminergic system were also evaluated in newly emerged male and female flies. All analyzed parameters in male flies were not significantly affected by atrazine exposure. However female flies exposed to atrazine at 10μM presented an increase in immobility time and a reduction in exploratory activity in the open field test, which was offset by an increase in the number of grooming episodes. Also, female flies exposed to 100μM of atrazine presented an increase in immobility time. Gene expression of DOPA decarboxylase and dopamine (DA) receptors were also increased only in females. The behavioural effects of atrazine exposure observed in female flies were due to a disturbance in the dopaminergic system.

Intermittent severe hypoxia induces plasticity within serotonergic and catecholaminergic neurons in the neonatal rat ventrolateral medulla.

5-HT neurons contribute to autoresuscitation and survival during intermittent severe hypoxia (IsH). In adults, catecholaminergic neurons in the ventrolateral medulla (VLM) contribute to the autonomic response to hypoxia. We hypothesized that 1) catecholaminergic neurons in the neonatal VLM are activated following IsH, 2) this activation is compromised following an acute loss of brain stem 5-HT, and 3) IsH induces cellular and/or transcriptomic plasticity within catecholaminergic and serotonergic neurons that are within or project to the VLM, respectively. To test these hypotheses, we treated rat pups with 6-fluorotryptophan, a tryptophan hydroxylase (TPH) inhibitor, and then exposed treated and vehicle controls to IsH or air. Along with immunohistochemistry to detect tyrosine hydroxylase (TH)- or Fos-positive neurons, we used RNA sequencing to resolve the effects of IsH and 5-HT deficiency on the expression of serotonergic and catecholaminergic system genes in the VLM. 5-HT deficiency compromised autoresuscitation and survival. IsH significantly increased the number of identifiable TH-positive VLM neurons, an effect enhanced by 5-HT deficiency (P = 0.003). Contrary to our hypothesis, 5-HT-deficient pups had significantly more Fos-positive neurons following IsH (P = 0.008) and more activated TH-positive neurons following IsH or air (P = 0.04). In both groups the expression of the 5-HT transporter and TPH2 was increased following IsH. In 5-HT-deficient pups, the expression of the inhibitory 5-HT1A receptor was decreased following IsH, while the expression of DOPA decarboxylase was increased. These data show that the serotonergic and catecholaminergic systems in the VLM of the neonatal rat are dynamically upregulated by IsH, potentially adapting cardiorespiratory responses to severe hypoxia.

Clinical significance of dopa decarboxylase expression in gastric peritoneal lavage in patients with gastric adenocarcinoma

Clinical significance of dopa decarboxylase expression in gastric peritoneal lavage in patients with gastric adenocarcinoma

Expression and functions of dopa decarboxylase in the silkworm, Bombyx mori was regulated by molting hormone

Insect molting is an important developmental process of metamorphosis, which is initiated by molting hormone. Molting includes the activation of dermal cells, epidermal cells separation, molting fluid secretion, the formation of new epidermis and old epidermis shed and other series of continuous processes. Polyphenol oxidases, dopa decarboxylase and acetyltransferase are necessary enzymes for this process. Traditionally, the dopa decarboxylase (BmDdc) was considered as an enzyme for epidermal layer's tanning and melanization. This work suggested that dopa decarboxylase is one set of the key enzymes in molting, which closely related with the regulation of ecdysone at the time of biological molting processes. The data showed that the expression peak of dopa decarboxylase in silkworm is higher during molting stage, and decreases after molting. The significant increase in the ecdysone levels of haemolymph was also observed in the artificially fed silkworm larvae with ecdysone hormone. Consistently, the dopa decarboxylase expression was significantly elevated compared to the control. BmDdc RNAi induced dopa decarboxylase expression obviously declined in the silkworm larvae, and caused the pupae appeared no pupation or incomplete pupation. BmDdc was mainly expressed and stored in the peripheral plasma area near the nucleus in BmN cells. In larval, BmDdc was mainly located in the brain and epidermis, which is consisted with its function in sclerotization and melanization. Overall, the results described that the dopa decarboxylase expression is regulated by the molting hormone, and is a necessary enzyme for the silkworm molting.

The expression of dopa decarboxylase and dopamine beta hydroxylase and their responding to bacterial challenge during the ontogenesis of scallop Chlamys farreri

Dopa decarboxylase (DDC) and dopamine beta hydroxylase (DBH) is responsible for the synthesis of dopamine and norepinephrine, respectively. In the present study, dopa decarboxylase (CfDDC) and dopamine beta hydroxylase (CfDBH) were selected as indicator to investigate the development of catecholaminergic nervous system in the larvae of scallop Chlamys farreri. The CfDDC and CfDBH transcripts were all detectable during the whole ontogenesis expect for the CfDDC transcripts in 2-cell embryos stage. The expression level of CfDDC and CfDBH mRNA increased significantly in the veliger stage, and reached the peak in late (35.64-fold, P < 0.05) and mid-veliger (400.21-fold, P < 0.05) larvae, respectively. By immunofluorescence, two CfDDC immunoreactive areas were observed in the trochophore and D-hinged larvae, and then three CfDDC immunoreactive areas and two immunopositive fibres formed in early and late veliger larvae, respectively. Two CfDBH immunopositive fibers appeared initially in the early D-hinged stage, and another two similar fibers developed in the late D-hinged stage. The bacteria Vibrio anguillarum challenge could induce the mRNA expression of CfDDC and CfDBH in different developmental stage. The significantly increase of CfDDC mRNA was observed in the trochophore larvae at 12 h (8.61-fold, P < 0.05) and in late D-hinged larvae at 24 h (1.56-fold, P < 0.05) post challenge. The expression level of CfDBH mRNA decreased significantly in late D-hinged larvae at 6 h (0.45-fold, P < 0.05), whereas it increased significantly in late veliger larvae at 12 h after bacterial challenge (14.52-fold, P < 0.05). These results concluded that the scallop catecholaminergic nervous system appeared firstly as the form of dopaminergic neurons in the trochophore larvae, and the developing catecholaminergic nervous system in the trochophore, D-hinged and veliger larvae of scallop could respond to the immune stimulation in different patterns.