H OH metabolites OH Article Substantively Lowered Levels of Pantothenic Acid (Vitamin B5) in Several Regions of the Human Brain in Parkinson’s Disease Dementia Melissa Scholefield 1,* , Stephanie J. Church 1, Jingshu Xu 1,2, Stefano Patassini 2, Nigel M. Hooper 3, Richard D. Unwin 1,4 and Garth J. S. Cooper 1,2,* 1 Centre for Advanced Discovery & Experimental Therapeutics, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9NT, UK; [email protected] (S.J.C.); [email protected] (J.X.); [email protected] (R.D.U.) 2 School of Biological Sciences, Faculty of Science, University of Auckland, Private Bag 92 019, Auckland 1142, New Zealand; [email protected] 3 Division of Neuroscience & Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9NT, UK; [email protected] 4 Stoller Biomarker Discovery Centre & Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Citylabs 1.0 (Third Floor), Nelson Street, Manchester M13 9NQ, UK * Correspondence: melissa.scholefi[email protected] (M.S.); [email protected] (G.J.S.C.) Abstract: Pantothenic acid (vitamin B5) is an essential trace nutrient required for the synthesis of Citation: Scholefield, M.; Church, coenzyme A (CoA). It has previously been shown that pantothenic acid is significantly decreased S.J.; Xu, J.; Patassini, S.; Hooper, N.M.; in multiple brain regions in both Alzheimer’s disease (ADD) and Huntington’s disease (HD). The Unwin, R.D.; Cooper, G.J.S. current investigation aimed to determine whether similar changes are also present in cases of Substantively Lowered Levels of Parkinson’s disease dementia (PDD), another age-related neurodegenerative condition, and whether Pantothenic Acid (Vitamin B5) in such perturbations might occur in similar regions in these apparently different diseases. Brain tissue Several Regions of the Human Brain was obtained from nine confirmed cases of PDD and nine controls with a post-mortem delay of in Parkinson’s Disease Dementia. 26 h or less. Tissues were acquired from nine regions that show high, moderate, or low levels of Metabolites 2021, 11, 569. https:// neurodegeneration in PDD: the cerebellum, motor cortex, primary visual cortex, hippocampus, doi.org/10.3390/metabo11090569 substantia nigra, middle temporal gyrus, medulla oblongata, cingulate gyrus, and pons. A targeted ultra–high performance liquid chromatography—tandem mass spectrometry (UHPLC-MS/MS) Academic Editor: Peter Meikle approach was used to quantify pantothenic acid in these tissues. Pantothenic acid was significantly decreased in the cerebellum (p = 0.008), substantia nigra (p = 0.02), and medulla (p = 0.008) of PDD Received: 14 July 2021 Accepted: 23 August 2021 cases. These findings mirror the significant decreases in the cerebellum of both ADD and HD cases, Published: 25 August 2021 as well as the substantia nigra, putamen, middle frontal gyrus, and entorhinal cortex of HD cases, and motor cortex, primary visual cortex, hippocampus, middle temporal gyrus, cingulate gyrus, and Publisher’s Note: MDPI stays neutral entorhinal cortex of ADD cases. Taken together, these observations indicate a common but regionally with regard to jurisdictional claims in selective disruption of pantothenic acid levels across PDD, ADD, and HD. published maps and institutional affil- iations. Keywords: pantothenic acid; vitamin B5; Parkinson’s disease dementia; mass spectrometry; Alzheimer’s disease; Huntington’s disease; metabolomics Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. 1. Introduction This article is an open access article Parkinson’s disease (PD) is a common neurodegenerative disorder, primarily charac- distributed under the terms and terised clinically by bradykinesia, resting tremor, and rigidity, and neuropathologically by conditions of the Creative Commons extensive dopaminergic neuronal loss and accumulation of α-synuclein deposits known Attribution (CC BY) license (https:// as Lewy bodies. These changes occur most severely within the substantia nigra pars com- creativecommons.org/licenses/by/ pacta, but also throughout other regions of the brain [1–3]. As well as motor dysfunction, 4.0/). Metabolites 2021, 11, 569. https://doi.org/10.3390/metabo11090569 https://www.mdpi.com/journal/metabolites Metabolites 2021, 11, 569 2 of 12 cognitive impairment is a common symptom in PD as the disease progresses, with up to 46% of individuals going on to develop Parkinson’s disease dementia (PDD) in the ten years following initial diagnosis [4], and up to 80% by twenty years [5]. Despite how common the condition is, the causes and mechanisms of PDD remain poorly characterised. Most cases are sporadic with no identifiable cause, and treatments remain purely symptomatic, with even the most promising clinical trials thus far being unable to slow, stop, or reverse the progression of the disease. This is also the case with other similar neurodegenerative diseases, such as Alzheimer’s (ADD) and Huntington’s disease (HD), which also currently have only symptomatic treatments despite extensive interest and studies into causes, mechanisms, and potential treatments [6]. These neurodegenerative diseases share several characteristics. Age is a primary risk factor for the development of symptoms (although HD is always caused by a dominant autosomal mutation in the huntingtin gene; the development of symptomology generally occurs with older age), cerebral protein deposition is present in each condition (α-synuclein in PD, tau and amyloid-β in ADD, and huntingtin in HD), and the clinical presentation can show significant overlap, with increased risk of psychological complaints [7], issues with sleep [8], and difficulty walking [9], as well as the progressive development of cognitive impairment [10,11]. These findings have raised the question as to whether there may be common pathogenic insults present across multiple neurodegenerative diseases contributing to these similarities in presentation. Common disruptions in multiple metabolic pathways have already been identified in ADD and HD brains, including widespread urea [12–15] and glucose increases [13,16–18], dysregulation of glucose and purine metabolism path- ways [13,16,17,19,20], and decreases in the essential nutrient pantothenic acid [21,22], also known as vitamin B5. Pantothenic acid is essential for the synthesis of coenzyme A (CoA), a molecule with extensive roles in metabolism including in the tricarboxylic acid (TCA) cycle, fatty acid metabolism, and acetylcholine and myelin synthesis, amongst others. Dysregulation of pantothenic acid could disrupt the supply of this essential molecule, with widespread downstream metabolic complications. Inborn mutations in the pantothenate kinase 2 gene (PKAN2), which is an intermediate in the CoA synthesis pathway, are associated with a disease known as pantothenate kinase-associated neurodegeneration [23], a condition characterised by severe brain damage within the basal ganglia and progressive cognitive and motor dysfunction including parkinsonism. Levels of pantothenic acid have not, to our knowledge, been investigated previously in the PDD brain. Thus, this investigation is, to our knowledge, the first to report dysreg- ulation of cerebral pantothenic acid in PDD, similar to that previously observed in ADD and HD. 2. Results 2.1. Cohort Characterisation Cases and controls were matched for age, sex, post-mortem delay (PMD), and brain weight, with no significant differences in any of these variables (see Table1). Samples were acquired with the lowest PMD possible, with a maximum of 26 h. Additional metadata, including cause of death and disease staging, were also obtained for all samples (see Supplementary Material A). Due to a lack of available SN tissue for two controls, two additional, replacement SN samples (C10 and C11) were obtained from different donors to those employed for the other brain regions. When the revised SN cohort was analysed, it was still matched for age, sex, and brain weight, but cases had a lower PMD than controls (p = 0.03; see Table1). Metabolites 2021, 11, 569 3 of 12 Table 1. Comparison of Brain Bank Groups. Gender (% Male) Age at Death (Years) PMD (Hours) Controls 70 19.8 44 (n = 9) (61–79) (12.5–26.0) SN Controls 70 20.6 44 (n = 9) † (62–79) (10.8–26.0) Cases 73 14.6 66 (n = 9) † (61–81) (4.3–21.9) * Mean (range) age, PMD, brain weight and Braak stage. * p < 0.05 between cases and controls as determined by Mann–Whitney U Test. † Brain weight not available for one sample. See Supplementary Material A for individual data. 2.2. Pantothenic Acid Analysis Concentrations of pantothenic acid were found to be significantly lower in the CB (p = 0.008), SN (p = 0.02), and MED (p = 0.008) of cases compared to controls (see Table2 and Figure1a). In these three regions, there was a decrease of approximately 40% in PDD cases. There was also a suggestion of decreased pantothenic acid in the pons, but this did not reach significance (p = 0.0503). Inter-regional concentrations of pantothenic acid were consistent, with no significant differences between any two regions in either cases or controls (data not shown). A ROC curve was generated using values from all three regions showing significant case–control differences (SN, CB, and MED; see Figure1b). The ROC curve has an