Aromatic L-amino Acid Decarboxylase Research Articles

Alzheimer’s and Parkinson’s disease drugs side effects

IntroductionAlzheimer’s and Parkinson’s disease are neurodegenerative disorders with life limiting conditions. The symptomatic pharmacological therapeutic strategies unfortunately are also related to undesirable side effects. Acetylcholinesterase inhibitors administered to Alzheimer’s disease patients increase cholinergic transmission in cortex and hippocampus.Antiparkinsonian drugs increase dopaminergic system activity, to compensate for dopaminergic neurons’ degeneration in corpus striatum, therefore supplying the imbalance of these neurotransmitters in these degenerative areas.But undesirable the increase of these neurotransmitters in other cerebral and peripheral areas brings us important side effectsObjectivesTo study Alzheimer’s cholinergic drugs and Parkinson’s dopaminergic drugs’ side effectsMethods This retrospective study included 107 geriatric patients enrolled in a private long-term care institution. 79 patients with Alzheimer’s disease had mean age of 88.11 ± 5,78 years old, mean weight of 61.62 ± 13.10 kg. 28 patients with Parkinson’s disease had mean age of 84.93 ± 5.71 years old, weight mean 66.36 ± 2.83 kg.ResultsAlzheimer’s disease patients 41.77% (33) received. Acetylcholinesterase inhibitors (Donepezil, galantamine and rivastigmine) Psychomotor agitation and aggressive behavior 63.666% and nausea (15%) were observed in the patients treated with these drugs. The association of L-DOPA and DOPA decarboxylase inhibitors (benserazide) were administered to 53%(15) of the Parkinson’s disease patients in doses between 2.0-19.0 mg/kg/day. L-DOPA associated to catechol-O-methyltransferase inhibitor (entacapone) 3 mg/kg/day were given to 7.14% (2) patients. Bromocriptine 0.04 mg/kg/day was given to 3.57% (1) patients. Mental confusion and hallucination side effects were observed in 53.33% (8) patients treated with L-DOPA associated with the DOPA decarboxylase inhibitor (benserazide).ConclusionsThe increase of cholinergic activity due to the acetylcholinesterase inhibitors in the Nigro- striatal pathway could be related to psychomotor agitation in Alzheimer’s disease patients in a similar way to akathisia induced by neuroleptics. The increase of dopamine levels due to the administration of L-DOPA, in corpus striatum improved Parkinson’s disease symptoms although the increase of dopaminergic activity at mesocortical pathways may be related to confusion and hallucination observed in these patients. Adjustments in dosage of these drugs could provide improvement in these patients’ daily life conditions.Disclosure of InterestNone Declared

Pharmacometabolomics and mass spectrometry imaging approach to reveal the neurochemical mechanisms of Polygala tenuifolia

Polygala tenuifolia, commonly known as Yuanzhi (YZ) in Chinese, has been shown to possess anti-insomnia properties. However, the material basis and the mechanism underlying its sedative-hypnotic effects remain unclear. Herein, we investigated the active components and neurochemical mechanism of YZ extracts using liquid chromatography tandem mass spectrometry (LC-MS/MS)-based pharmacometabolomics and mass spectrometry imaging (MSI)-based spatial resolved metabolomics. According to the results, 17 prototypes out of 101 ingredients in the YZ extract were detected in both the plasma and brain, which might be the major components contributing to the sedative-hypnotic effects. Network pharmacology analysis revealed that these prototypes may exert their effects through neuroactive ligand-receptor interaction, serotonergic synapse, dopaminergic synapse, and dopaminergic synapse, among other pathways. LC-MS/MS-based targeted metabolomics and Western blot (WB) revealed that tryptophan-serotonin-melatonin (Trp-5-HT-Mel) and tyrosine-norepinephrine-adrenaline (Tyr-Ne-Ad) are the key regulated pathways. Dopa decarboxylase (DDC) upregulation and phenylethanolamine N-methyltransferase (PNMT) downregulation further confirmed these pathways. Furthermore, MSI-based spatially resolved metabolomics revealed notable alterations in 5-HT in the pineal gland (PG), and Ad in the brainstem, including the middle brain (MB), pons (PN), and hypothalamus (HY). In summary, this study illustrates the efficacy of an integrated multidimensional metabolomics approach in unraveling the sedative-hypnotic effects and neurochemical mechanisms of a Chinese herbal medicine, YZ.

Functional characterization of promiscuous tryptophan decarboxylase from indole alkaloids producing Rauvolfia tetraphylla L.

The enzyme Tryptophan decarboxylase (TDC, EC 4.1.1.28) gene facilitates the conversion of tryptophan to tryptamine. A new gene encoding TDC was identified from the alkaloid producing plant Rauvolfia tetraphylla by transcriptome analysis, termed as RtTDC. It contains 1,500 base pair which encodes an open reading frame for 499-amino-acid polypeptide with molecular mass of 55729.29 kDa and isoelectric point of 5.37. Multiple sequence alignment and phylogenetic tree analysis showed the closest similarity (95.3 %) with the TDC from the Rauvolfia verticillata. This enzyme has property of recombinant tryptophan decarboxylase from R. tetraphylla was characterized. The potential activity of tryptophan decarboxylase specific to L-tryptophan may contribute to the biosynthesis of indole alkaloids in R. tetraphylla. The finding of tryptophan metabolites in R. tetraphylla plants is a novel report, lead to hypothesize the existence of TDC enzymatic activity, from which aromatic amino acid decarboxylases is formed. These results support the in-silico annotation of the examined protein sequences of R. tetraphylla as TDC and suggest the involvement of TDC enzymatic activity in this plant. Molecular modeling of the TDC gene evidencing the reliability, stability and the structural similarities of the R. tetraphylla TDC gene with R. verticillata TDC gene. The L-tryptophan used as ligand in docking analysis to verify the TDC gene enzymatic activity for synthesis of Indole alkaloids. High performance liquid chromatography data analyses of RtTDC catalyzed reaction mixture confirmed the catalytically decarboxylative activity of RtTDC.

Ophthalmate is a new regulator of motor functions via CaSR: implications for movement disorders.

Dopamine's role as the principal neurotransmitter in motor functions has long been accepted. We broaden this conventional perspective by demonstrating the involvement of non-dopaminergic mechanisms. In mouse models of Parkinson's disease, we observed that L-DOPA elicited a substantial motor response even when its conversion to dopamine was blocked by inhibiting the enzyme aromatic amino acid decarboxylase (AADC). Remarkably, the motor activity response to L-DOPA in the presence of an AADC inhibitor (NSD1015) showed a delayed onset, yet greater intensity and longer duration, peaking at 7 h, compared to when L-DOPA was administered alone. This suggests an alternative pathway or mechanism, independent of dopamine signalling, mediating the motor functions. We sought to determine the metabolites associated with the pronounced hyperactivity observed, using comprehensive metabolomics analysis. Our results revealed that the peak in motor activity induced by NSD1015/L-DOPA in Parkinson's disease mice is associated with a surge (20-fold) in brain levels of the tripeptide ophthalmic acid (also known as ophthalmate in its anionic form). Interestingly, we found that administering ophthalmate directly to the brain rescued motor deficits in Parkinson's disease mice in a dose-dependent manner. We investigated the molecular mechanisms underlying ophthalmate's action and discovered, through radioligand binding and cAMP-luminescence assays, that ophthalmate binds to and activates the calcium-sensing receptor (CaSR). Additionally, our findings demonstrated that a CaSR antagonist inhibits the motor-enhancing effects of ophthalmate, further solidifying the evidence that ophthalmate modulates motor functions through the activation of the CaSR. The discovery of ophthalmate as a novel regulator of motor function presents significant potential to transform our understanding of brain mechanisms of movement control and the therapeutic management of related disorders.

Effects of Aspirin Eugenol Ester on Liver Oxidative Damage and Energy Metabolism in Immune-Stressed Broilers.

The aim of this study was to investigate the effects of aspirin eugenol ester (AEE) on liver oxidative damage and energy metabolism in immune-stressed broilers. In total, 312 broilers were divided into 4 groups (saline, LPS, SAEE, and LAEE). Broilers in the saline and LPS groups were fed a basal diet; the SAEE and LAEE groups had an added 0.01% AEE in their diet. Broilers in the LPS and LAEE groups were injected with lipopolysaccharides, while the saline and SAEE groups were injected with saline. Results showed that AEE increased the body weight, average daily gain, and average daily feed intake, as well as decreasing the feed conversion ratio of immune-stressed broilers. AEE protects against oxidative damage in immune-stressed broiler livers by elevating the total antioxidant capacity, superoxide dismutase activity, and glutathione S-transferase alpha 3 (GSTA3) and glutaredoxin 2 (GLRX2) expression, while decreasing malondialdehyde content. AEE lessened inflammation by reducing prostaglandin-F2α production and prostaglandin-endoperoxide synthase 2 (PTGS2) and interleukin-1beta (IL-1β) expression. AEE decreased oxidative phosphorylation rates by increasing succinic acid levels and lowering both adenosine diphosphate (ADP) levels and ceroid lipofuscinosis neuronal 5 (CLN5) expression. AEE modulated the metabolism of phenylalanine, tyrosine, lipids, and cholesterol by reducing the phenyllactate and L-arogenate levels, lowering dopachrome tautomerase (DCT) and apolipoprotein A4 (APOA4) expression, and increasing phenylpyruvic acid and dopa decarboxylase (DDC) expression. In summary, AEE can effectively alleviate liver oxidative damage and energy metabolism disorders in immune-stressed broilers.

Comprehensive proteomics of CSF, plasma, and urine identify DDC and other biomarkers of early Parkinson’s disease

Parkinson’s disease (PD) starts at the molecular and cellular level long before motor symptoms appear, yet there are no early-stage molecular biomarkers for diagnosis, prognosis prediction, or monitoring therapeutic response. This lack of biomarkers greatly impedes patient care and translational research—l-DOPA remains the standard of care more than 50 years after its introduction. Here, we performed a large-scale, multi-tissue, and multi-platform proteomics study to identify new biomarkers for early diagnosis and disease monitoring in PD. We analyzed 4877 cerebrospinal fluid, blood plasma, and urine samples from participants across seven cohorts using three orthogonal proteomics methods: Olink proximity extension assay, SomaScan aptamer precipitation assay, and liquid chromatography–mass spectrometry proteomics. We discovered that hundreds of proteins were upregulated in the CSF, blood, or urine of PD patients, prodromal PD patients with DAT deficit and REM sleep behavior disorder or anosmia, and non-manifesting genetic carriers of LRRK2 and GBA mutations. We nominate multiple novel hits across our analyses as promising markers of early PD, including DOPA decarboxylase (DDC), also known as l-aromatic acid decarboxylase (AADC), sulfatase-modifying factor 1 (SUMF1), dipeptidyl peptidase 2/7 (DPP7), glutamyl aminopeptidase (ENPEP), WAP four-disulfide core domain 2 (WFDC2), and others. DDC, which catalyzes the final step in dopamine synthesis, particularly stands out as a novel hit with a compelling mechanistic link to PD pathogenesis. DDC is consistently upregulated in the CSF and urine of treatment-naïve PD, prodromal PD, and GBA or LRRK2 carrier participants by all three proteomics methods. We show that CSF DDC levels correlate with clinical symptom severity in treatment-naïve PD patients and can be used to accurately diagnose PD and prodromal PD. This suggests that urine and CSF DDC could be a promising diagnostic and prognostic marker with utility in both clinical care and translational research.

Modeling of new markers for the diagnosis and prognosis of pancreatic cancer based on the transition from inflammation to cancer.

Pancreatic adenocarcinoma (PAAD) is a lethal disease with a poor prognosis. Genes involved in acute pancreatitis (AP) or chronic pancreatitis (CP) might be important for PAAD development. This study sought to identify potential PAAD diagnosis markers and to establish a PAAD prognosis prediction model based on AP- and CP-related genes. The significantly differentially expressed genes in both AP or CP and PAAD were obtained by a bioinformatics analysis. A risk-score model for predicting survival was constructed based on The Cancer Genome Atlas (TCGA) data and validated using an International Cancer Genome Consortium (ICGC) cohort. Protein expression and the effects of the genes in the risk models were validated by immunohistochemistry, or Cell Counting Kit-8 (CCK-8) and transwell assays. The study sample data included six AP tissue samples and five normal pancreatic tissue samples, six CP tissue samples and six normal pancreatic tissue samples from the Gene Expression Omnibus (GEO) expression profiling microarrays GSE109227 and GSE41418 data sets, respectively, and fragments per kilobase per million mapped fragments (FPKM) data from four normal controls and 150 PAAD cases from TCGA database, and 182 cancer patient samples with complete survival prognostic data from the ICGC database. In total, 508 significantly differentially expressed genes were found in both AP or CP and PAAD. Trefoil factor 2 (TFF2), tubulointerstitial nephritis antigen (TINAG), trefoil factor 1 (TFF1), aquaporin 5 (AQP5), SAM pointed domain containing ETS transcription factor (SPDEF), anterior gradient protein 2 (AGR2), apolipoprotein B messenger RNA editing enzyme catalytic subunit 1 (APOBEC1), kallikrein-related peptidase 6 (KLK6), dopa decarboxylase (DDC), mucin 13 (MUC13), claudin 18 (CLDN18), annexin A10 (ANXA10), and tetraspanin 1 (TSPAN1) were found to be present in PAAD and had the largest fold change. A risk-score model, comprising 19 genes, was constructed for prognostic prediction. A high-risk score indicated a poor prognosis. TINAG, DDC, SPDEF, and APOBEC1 proteins were increased in PAAD, while TINAG and DDC were correlated with the pathologic grade. Decreased TINAG, APOBEC1, transmembrane protein 94 (TMEM94), and kelch like family member 36 (KLHL36) expression inhibited PAAD cell proliferation, while decreased SPDEF, TMEM94, and KLHL36 expression significantly inhibited PAAD cell migration. The AP and CP co-related genes were significantly correlated with PAAD. TINAG, DDC, SPDEF, and APOBEC1 could serve as new PAAD predictors. The risk model developed in this study could be used to predict the prognosis of PAAD patients.

The Relationship Between COMT and MAO-B Gene Polymorphisms with Levodopa in Parkinson’s Disease Patients; A Review

Parkinson's disease is a degenerative nervous system disorder caused by the death of dopamine-producing cells in the substantia nigra. Dopaminergic treatment could alleviate motor symptoms for a period. One of the effective dopaminergic medications for symptomatic relief was Levodopa and dopamine agonists. Clinically, Levodopa was always combined with Dopa Decarboxylase (DDC) inhibitors, which redirected Levodopa metabolism towards the COMT pathway, increasing its bioavailability in the central nervous system. The purpose of this article was to investigate the relationship between COMT and MAO-B gene polymorphisms and Levodopa in Parkinson's disease patients, starting by gathering literature on the association between COMT and MAO-B polymorphisms and Levodopa in Parkinson's disease patients using various databases. Reviewed literature revealed that the most frequent polymorphism in the COMT gene was rs4680. Some polymorphisms significantly impacted the treatment of Parkinson's disease patients. However, despite efforts to identify genetic factors influencing the risk of side effects or treatment ineffectiveness, the role of pharmacogenetics in Parkinson's disease has not been fully explored and lacks consistent clinical recommendations. Further research was needed to tailor treatment to individual polymorphisms so that pharmacogenomic approaches could be applied more consistently

Screening and preliminary analysis of differentially expressed genes in quail embryos for feather colour based on RNA-Sequencing

The purpose of this study was to use RNA-Sequencing (RNA-Seq) to screen differentially expressed genes (DEGs) and analyse transcriptomic data from embryonic skin tissues of maroon-feather and white-feather quails. The transcriptome of embryonic skin tissues from quails was sequenced using the Illumina HiSeqTM 2000 sequencing platform. A total of 2 512 DEGs were found. Of these, 550 DEGs were up-regulated and 1 562 DEGs were down-regulated in the skin tissues of white-feather quail embryos. Five hundred and ninety-seven DEGs were enriched and annotated into 50 entries in Gene Ontology (GO) database. The total number of DEGs annotated in each entry in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database was 341, enriched in 230 pathways, of which the tight junction pathway and neuroactive ligand-receptor interaction were the most significantly enriched. Candidate genes were analysed using real-time quantitative reverse transcription polymerase chain reaction (to verify the accuracy and reliability of the RNA-Seq results. The relative expression of agouti signalling protein (ASIP) and DOPA decarboxylase (DDC) in white-feather quails were increased. Relative expression of homeobox D1 (HOXD1), cathepsin D (CTSD), keratin 2 (KRT2), methyl-CpG binding domain protein 2 (MBD2), and melatonin receptor 1 (MT1) were decreased. The results of this study provide useful data on the analysis of the feather colour regulatory mechanism in white- and maroon-feather quails.

A study on the association between gut microbiota, inflammation, and type 2 diabetes

Type 2 diabetes mellitus (T2DM) was reported to be associated with impaired immune response and alterations in microbial composition and function. However, the underlying mechanism remains elusive. To investigate the association among retinoic acid-inducible gene-I-like receptors (RLRs) signaling pathway, intestinal bacterial microbiome, microbial tryptophan metabolites, inflammation, and a longer course of T2DM, 14 patients with T2DM and 7 healthy controls were enrolled. 16S rRNA amplicon sequencing and untargeted metabolomics were utilized to analyze the stool samples. RNA sequencing (RNA-seq) was carried out on the peripheral blood samples. Additionally, C57BL/6J specific pathogen-free (SPF) mice were used. It was found that the longer course of T2DM could lead to a decrease in the abundance of probiotics in the intestinal microbiome. In addition, the production of microbial tryptophan derivative skatole declined as a consequence of the reduced abundance of related intestinal microbes. Furthermore, low abundances of probiotics, such as Bacteroides and Faecalibacterium, could trigger the inflammatory response by activating the RLRs signaling pathway. The increased level of the member of TNF receptor-associated factors (TRAF) family, nuclear factor kappa-B (NF-κB) activator (TANK), in the animal colon activated nuclear factor kappa B subunit 2 (NFκB2), resulting in inflammatory damage. In summary, it was revealed that the low abundances of probiotics could activate the RLR signaling pathway, which could in turn activate its downstream signaling pathway, NF-κB, highlighting a relationship among gut microbes, inflammation, and a longer course of T2DM.Key pointsHyperglycemia may suppress tryptophanase activity.The low abundance of Bacteroides combined with the decrease of Dopa decarboxylase (DDC) activity may lead to the decrease of the production of tryptophan microbial derivative skatole, and the low abundance of Bacteroides or reduced skatole may further lead to the increase of blood glucose by downregulating the expression of glucagon-like peptide-1 (GLP1).A low abundance of anti-inflammatory bacteria may induce an inflammatory response by triggering the RLR signaling pathway and then activating its downstream NF-κB signaling pathway in prolonged T2DM.

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.

Newborn screening for aromatic l-amino acid decarboxylase deficiency – Strategies, results, and implication for prevalence calculations

BackgroundAromatic l-amino acid decarboxylase deficiency (AADCD) is a rare, autosomal-recessive neurometabolic disorder caused by variants in dopa decarboxylase (DDC) gene, resulting in a severe combined deficiency of serotonin, dopamine, norepinephrine, and epinephrine. Birth prevalence of AADCD varies by population. In pilot studies, 3-O-methyldopa (3-OMD) was shown to be a reliable biomarker for AADCD in high-throughput newborn screening (NBS) allowing an early diagnosis and access to gene therapy. To evaluate the usefulness of this method for routine NBS, 3-OMD screening results from the largest three German NBS centers were analyzed. MethodsA prospective, multicenter (n = 3) NBS pilot study evaluated screening for AADCD by quantifying 3-OMD in dried blood spots (DBS) using tandem mass spectrometry (MS/MS). ResultsIn total, 766,660 neonates were screened from January 2021 until June 2023 with 766,647 with unremarkable AADCD NBS (766,443 by 1st-tier analysis and 204 by 2nd-tier analysis) and 13 with positive NBS result recalled for confirmatory diagnostics (recall-rate about 1:59,000).Molecular genetic analysis confirmed AADCD (c.79C > T p.[Arg27Cys] in Exon 2 und c.215 A > C p.[His72Pro] in Exon 3) in one infant. Another individual was highly suspected with AADCD but died before confirmation (overall positive predictive value 0.15). False-positive results were caused by maternal L-Dopa use (n = 2) and prematurity (30th and 36th week of gestation, n = 2). However, in 63% (n = 7) the underlying etiology for false positive results remained unexplained. Estimated birth prevalence (95% confidence interval) was 1:766,660 (95% CI 1:775,194; 1:769,231) to 1:383,330 (95% CI 1:384,615; 1:383,142). The identified child remained asymptomatic until last follow up at the age of 9 months. ConclusionsThe proposed screening strategy with 3-OMD detection in DBS is feasible and effective to identify individuals with AADCD. The estimated birth prevalence supports earlier estimations and confirms AADCD as a very rare disorder. Pre-symptomatic identification by NBS allows a disease severity adapted drug support to diminish clinical complications until individuals are old enough for the application of the gene therapy.

Aromatic L-Amino Acid Decarboxylase Deficiency: A Genetic Screening in Sicilian Patients with Neurological Disorders.

Aromatic L-amino acid decarboxylase deficiency (AADCd) is a rare autosomal recessive neurometabolic disorder caused by AADC deficiency, an enzyme encoded by the DDC gene. Since the enzyme is involved in the biosynthesis of serotonin and dopamine, its deficiency determines the lack of these neurotransmitters, but also of norepinephrine and epinephrine. Onset is early and the key signs are hypotonia, movement disorders (oculogyric crises, dystonia and hypokinesia), developmental delay and autonomic dysfunction. Taiwan is the site of a potential founder variant (IVS6+4A>T) with a predicted incidence of 1/32,000 births, while only 261 patients with this deficit have been described worldwide. Actually, the number of affected persons could be greater, given that the spectrum of clinical manifestations is broad and still little known. In our study we selected 350 unrelated patients presenting with different neurological disorders including heterogeneous neuromuscular disorders, cognitive deficit, behavioral disorders and autism spectrum disorder, for which the underlying etiology had not yet been identified. Molecular investigation of the DDC gene was carried out with the aim of identifying affected patients and/or carriers. Our study shows a high frequency of carriers (2.57%) in Sicilian subjects with neurological deficits, with a higher concentration in northern and eastern Sicily. Assuming these data as representative of the general Sicilian population, the risk may be comparable to some rare diseases included in the newborn screening programs such as spinal muscular atrophy, cystic fibrosis and phenylketonuria.

A position statement on the post gene-therapy rehabilitation of aromatic I-amino acid decarboxylase deficiency patients

Aromatic l-amino acid decarboxylase (AADC) deficiency is a rare genetic disorder of monoamine neurotransmitter synthesis that presents with a range of symptoms, including motor dysfunction and limited attainment of developmental motor milestones. The approval of eladocagene exuparvovec, a gene therapy for AADC deficiency with demonstrated efficacy for motor improvements, now expands the range of motor outcomes possible for patients with this disorder. However, recommendations and guidelines for therapy following treatment with gene therapy are lacking. To ensure patients can reach their full potential following treatment with gene therapy, it is essential they receive rehabilitation therapies designed specifically with their impairments and goals in mind. Therefore, we highlight specific rehabilitative needs of patients following gene therapy and propose a set of recommendations for the post-treatment period based on collective experiences of therapists, physicians, and caregivers treating and caring for patients with AADC deficiency who have been treated with gene therapy. These recommendations include a focus on periods of intensive therapy, facilitating active movements, training for functional abilities, cognitive and communication training, parent/caregiver empowerment, collaboration between therapists and caregivers to develop in-home programs, and the incorporation of supplemental forms of therapy that patients and their families may find more enjoyable and engaging. Many of these rehabilitative strategies may be employed prior to gene therapy. However, these recommendations will be valuable for therapists, caregivers, and wider treatment teams as they prepare for the post-treatment journey with these patients. Furthermore, the considerations and recommendations presented here may prove beneficial outside the AADC deficiency community as gene therapies and other treatments are developed and approved for other rare diseases.

Cloning, characterization and specificity of a new aromatic-L-amino-acid decarboxylases from Bufo bufo gargarizans

5-Hydroxytryptamine (5-HT) and its derivative bufotenine, which possess important physiological functions, are the primary active components in the secretions of toad parotid and skin gland. However, the biosynthetic pathway of these substances remains unclear in toads. To characterize toad's Aromatic-L-amino-acid decarboxylase (AADC), the key enzyme in the predicted 5-HT derivatives biosynthetic pathway, the full-length cDNA of AADC from Bufo bufo gargarizans (BbgAADC) was cloned from the parotoid gland of B. bufo gargarizans. The recombinant BbgAADC exhibited optimal expression in E. coli BL21 (DE3) containing pCold-BbgAADC after induction for 16 h at 15 °C with 0.3 mM IPTG, resulting in substantial yields of soluble proteins. The enzymological properties of BbgAADC were assessed, and it was determined that the optimal reaction temperature was 37 °C, the optimal pH was 8.6, and the optimum molar ratio of pyridoxal-5′-phosphate (PLP) to BbgAADC was found to be 3.6:1. Additionally, high substrate specificity was observed, as BbgAADC could catalyze the production of 5-HT from 5-hydroxytryptophan (5-HTP) but not dopamine or tryptamine from levodopa or tryptophan, respectively. The Km of the recombinant protein BbgAADC was 0.2918 mM and the maximum reaction rate (Vmax) was 1.182 μM·min−1 when 5-HTP was used as substrate. The Kcat was 0.0545 min−1, and Kcat/Km was 0.1868 mM−1·min−1. To elucidate the mechanism of BbgAADC, molecular docking was performed with PLP and 5-HTP, or the external aldimine formed by 5-HTP and PLP. The results indicated that the active sites for BbgAADC to bind with PLP were K303, H192, N300, A148, F309, T246, A273, and T147. W71, Y79, F80, P81, T82, H192, T246, N300, H302, F309, and R477 served as catalytically active sites for the binding of BbgAADC to 5-HTP. Furthermore, R447, W71, S149, N300, A148, and T147 of BbgAADC were involved in the decarboxylation reaction of the aldimine formed by PLP and 5-HTP.

Inherited Pediatric Neurotransmitter Disorders: Case Studies and Long-Term Outcomes

AbstractPrimary pediatric neurotransmitter disorders include genetic defects of neurotransmitter metabolism that may mimic common neurological conditions in children. Our objective was to evaluate the clinical experience and outcomes of affected patients. Five patients with primary neurotransmitter defects were identified in the neurometabolic database between 2004 and 2022. Two patients with 6-pyruvoyltetrahydropterin synthase deficiency and one with pyridoxine-dependent epilepsy (PDE) presented in the neonatal period. One patient with succinic semialdehyde dehydrogenase (SSADH) deficiency and one with aromatic l-amino acid decarboxylase (AADC) deficiency presented in later life. A diagnosis of cerebral palsy was revised following biochemical confirmation of SSADH deficiency. AADC deficiency was confirmed via exome sequencing and reduced activity on enzyme assay. Late diagnosis in the latter two cases was likely due to a low index of suspicion and lack of access to diagnostic tests in the country of origin. In two children with tetrahydrobiopterin deficiency, newborn screening results and atypical clinical features prompted investigations. An early diagnosis of PDE was established based on presenting features, a high index of suspicion, the presence of an identifiable biochemical marker and molecular genetic testing. Pediatric neurotransmitter disorders can be diagnosed based on a high clinical index of suspicion, availability of biochemical markers, and molecular genetic testing. These disorders, though rare, need to be included in the differential diagnosis of common neurological presentations in children as they may be potentially treatable. Outcomes and influencing factors in the present series are discussed in comparison to published data.

Detection of hidden intronic DDC variant in aromatic L-amino acid decarboxylase deficiency by adaptive sampling.

Aromatic l-amino acid decarboxylase (AADC) deficiency is an autosomal recessive neurotransmitter disorder caused by pathogenic DOPA decarboxylase (DDC) variants. We previously reported Japanese siblings with AADC deficiency, which was confirmed by the lack of enzyme activity; however, only a heterozygous missense variant was detected. We therefore performed targeted long-read sequencing by adaptive sampling to identify any missing variants. Haplotype phasing and variant calling identified a novel deep intronic variant (c.714+255 C > A), which was predicted to potentially activate the noncanonical splicing acceptor site. Minigene assay revealed that wild-type and c.714+255 C > A alleles had different impacts on splicing. Three transcripts, including the canonical transcript, were detected from the wild-type allele, but only the noncanonical cryptic exon was produced from the variant allele, indicating that c.714+255 C > A was pathogenic. Target long-read sequencing may be used to detect hidden pathogenic variants in unresolved autosomal recessive cases with only one disclosed hit variant.

Patient selection considerations for AADC deficiency gene therapy

AbstractBackgroundAromatic ʟ‐amino acid decarboxylase (AADC) deficiency is a rare, severe neurological disorder caused by pathogenic variants in the dopa decarboxylase (DDC) gene, resulting in a combined deficiency of monoamine neurotransmitters. Clinically, patients present with a range of dysfunctions that impact motor, autonomic, and cognitive development. The constellation of symptoms of AADC deficiency varies among patients, and clinical presentation falls across a wide spectrum. However, most patients with AADC deficiency experience significant impairments when compared with children with normal development, irrespective of genotype, phenotype, or disease severity. Further, AADC deficiency is associated with increased mortality.MethodsIn response to the recent approval of a disease‐modifying gene therapy for AADC deficiency, this review presents considerations for the selection of patients for treatment.ConclusionSuggested clinical criteria to determine whether a patient is a candidate for gene therapy are: (1) genetically and biochemically confirmed AADC deficiency; (2) lack of achievement of gross motor milestones and/or persistence of clinically significant movement disorders; (3) persistent neurocognitive or systemic symptoms secondary to AADC deficiency despite standard medical therapy; and (4) informed parental/guardian decision and consent to treatment.

Ccr2-dependent monocytes exacerbate intestinal inflammation and modulate gut serotonergic signaling following traumatic brain injury.

Traumatic brain injury (TBI) leads to acute gastrointestinal dysfunction and mucosal damage, resulting in feeding intolerance. C-C motif chemokine receptor 2 (Ccr2 + ) monocytes are crucial immune cells that regulate the gut's inflammatory response via the brain-gut axis. Using Ccr2 ko mice, we investigated the intricate interplay between these cells to better elucidate the role of systemic inflammation after TBI. A murine-controlled cortical impact model was used, and results were analyzed on postinjury days 1 and 3. The experimental groups included (1) sham C57Bl/6 wild type (WT), (2) TBI WT, (3) sham Ccr2 ko , and (4) TBI Ccr2 ko . Mice were euthanized on postinjury days 1 and 3 to harvest the ileum and study intestinal dysfunction and serotonergic signaling using a combination of quantitative real-time polymerase chain reaction, immunohistochemistry, fluorescein isothiocyanate-dextran motility assays, and flow cytometry. Student's t test and one-way analysis of variance were used for statistical analysis, with significance achieved when p < 0.05. Traumatic brain injury resulted in severe dysfunction and dysmotility of the small intestine in WT mice as established by significant upregulation of inflammatory cytokines iNOS , Lcn2 , TNFα , and IL1β and the innate immunity receptor toll-like receptor 4 ( Tlr4 ). This was accompanied by disruption of genes related to serotonin synthesis and degradation. Notably, Ccr2 ko mice subjected to TBI showed substantial improvements in intestinal pathology. Traumatic brain injury Ccr2 ko groups demonstrated reduced expression of inflammatory mediators ( iNOS , Lcn2 , IL1β , and Tlr4 ) and improvement in serotonin synthesis genes, including tryptophan hydroxylase 1 ( Tph1 ) and dopa decarboxylase ( Ddc ). Our study reveals a critical role for Ccr2 + monocytes in modulating intestinal homeostasis after TBI. Ccr2 + monocytes aggravate intestinal inflammation and alter gut-derived serotonergic signaling. Therefore, targeting Ccr2 + monocyte-dependent responses could provide a better understanding of TBI-induced gut inflammation. Further studies are required to elucidate the impact of these changes on brain neuroinflammation and cognitive outcomes.

A clinical case of severe aromatic L-amino acid decarboxylase deficiency

We present a case of a rare disease, aromatic L-amino acid decarboxylase deficiency (AADCD), with delayed diagnosis even after a pathogenic mutation indicative of AADCD was found. In most cases, AADCD causes marked impairment of motor and psycho- speech development and is accompanied by severe episodes of dystonia – oculogyric crises. The careful attention of neurologists, pediatricians, geneticists, gastroenterologists, and pulmonologists in cases of a complex set of diverse symptoms determines the success of early diagnosis and the earliest possible prescription of modern gene replacement therapy for AADCD.