Pantothenate Kinase Research Articles

Relief of CoA sequestration and restoration of mitochondrial function in a mouse model of propionic acidemia.

Propionic acidemia (PA, OMIM 606054) is a devastating inborn error of metabolism arising from mutations that reduce the activity of the mitochondrial enzyme propionyl-CoA carboxylase (PCC). The defects in PCC reduce the concentrations of nonesterified coenzyme A (CoASH), thus compromising mitochondrial function and disrupting intermediary metabolism. Here, we use a hypomorphic PA mouse model to test the effectiveness of BBP-671 in correcting the metabolic imbalances in PA. BBP-671 is a high-affinity allosteric pantothenate kinase activator that counteracts feedback inhibition of the enzyme to increase the intracellular concentration of CoA. Liver CoASH and acetyl-CoA are depressed in PA mice and BBP-671 treatment normalizes the cellular concentrations of these two key cofactors. Hepatic propionyl-CoA is also reduced by BBP-671 leading to an improved intracellular C3:C2-CoA ratio. Elevated plasma C3:C2-carnitine ratio and methylcitrate, hallmark biomarkers of PA, are significantly reduced by BBP-671. The large elevations of malate and α-ketoglutarate in the urine of PA mice are biomarkers for compromised tricarboxylic acid cycle activity and BBP-671 therapy reduces the amounts of both metabolites. Furthermore, the low survival of PA mice is restored to normal by BBP-671. These data show that BBP-671 relieves CoA sequestration, improves mitochondrial function, reduces plasma PA biomarkers, and extends the lifespan of PA mice, providing the preclinical foundation for the therapeutic potential of BBP-671.

Hitting them where it hurts: Pantothenate kinase targeting in pathogenic fungi

In this issue of Structure, Gihaz and colleagues develop antifungal compounds targeting fungal pantothenate kinase (PanK). Through utilization of high-throughput chemical screening, along with biochemical and functional analyses and newly solved fungal PanK crystal structures, high-affinity inhibitors are produced, and invaluable insights into the mechanisms of fungal PanK are gained.

Vitamin B5 rewires Th17 cell metabolism via impeding PKM2 nuclear translocation.

Metabolic rewiring is essential for Th17 cells' functional identity to sense and interpret environmental cues. However, the environmental metabolic checkpoints with specific regulation of Th17 cells, manifesting potential therapeutic opportunities to autoimmune diseases, remain largely unknown. Here, by screening more than one hundred compounds derived from intestinal microbes or diet, we found that vitamin B5 (VB5) restrains Th17 cell differentiation as well as related autoimmune diseases such as experimental autoimmune encephalomyelitis and colitis. Mechanistically, VB5 is catabolized into coenzyme A (CoA) in a pantothenate kinase (PANK)-dependent manner, and in turn, CoA binds to pyruvate kinase isoform 2 (PKM2) to impede its phosphorylation and nuclear translocation, thus inhibiting glycolysis and STAT3 phosphorylation. In humans, reduced serum VB5 levels are found in both IBD and MS patients. Collectively, our study demonstrates a roleof VB5 in Th17 cell metabolic reprograming, thus providing a potential therapeutic intervention for Th17 cell-associated autoimmune diseases.

Bi-Allelic Mutations in Zebrafish pank2 Gene Lead to Testicular Atrophy and Perturbed Behavior without Signs of Neurodegeneration.

Coenzyme A (CoA) is an essential cofactor in all living organisms, being involved in a large number of chemical reactions. Sequence variations in pantothenate kinase 2 (PANK2), the first enzyme of CoA biosynthesis, are found in patients affected by Pantothenate Kinase Associated Neurodegeneration (PKAN), one of the most common forms of neurodegeneration, with brain iron accumulation. Knowledge about the biochemical and molecular features of this disorder has increased a lot in recent years. Nonetheless, the main culprit of the pathology is not well defined, and no treatment option is available yet. In order to contribute to the understanding of this disease and facilitate the search for therapies, we explored the potential of the zebrafish animal model and generated lines carrying biallelic mutations in the pank2 gene. The phenotypic characterization of pank2-mutant embryos revealed anomalies in the development of venous vascular structures and germ cells. Adult fish showed testicular atrophy and altered behavioral response in an anxiety test but no evident signs of neurodegeneration. The study suggests that selected cell and tissue types show a higher vulnerability to pank2 deficiency in zebrafish. Deciphering the biological basis of this phenomenon could provide relevant clues for better understanding and treating PKAN.

High-resolution crystal structure and chemical screening reveal pantothenate kinase as a new target for antifungal development

Fungal infections are the leading cause of mortality by eukaryotic pathogens, with an estimated 150 million severe life-threatening cases and 1.7 million deaths reported annually. The rapid emergence of multidrug-resistant fungal isolates highlights the urgent need for new drugs with new mechanisms of action. In fungi, pantothenate phosphorylation, catalyzed by PanK enzyme, is the first step in the utilization of pantothenic acid and coenzyme A biosynthesis. In all fungi sequenced so far, this enzyme is encoded by a single PanK gene. Here, we report the crystal structure of a fungal PanK alone as well as with high-affinity inhibitors from a single chemotype identified through a high-throughput chemical screen. Structural, biochemical, and functional analyses revealed mechanisms governing substrate and ligand binding, dimerization, and catalysis and helped identify new compounds that inhibit the growth of several Candida species. The data validate PanK as a promising target for antifungal drug development.

Generation and Validation of an Anti-Human PANK3 Mouse Monoclonal Antibody.

Coenzyme A (CoA) is an essential co-factor at the intersection of diverse metabolic pathways. Cellular CoA biosynthesis is regulated at the first committed step—phosphorylation of pantothenic acid—catalyzed by pantothenate kinases (PANK1,2,3 in humans, PANK3 being the most highly expressed). Despite the critical importance of CoA in metabolism, the differential roles of PANK isoforms remain poorly understood. Our investigations of PANK proteins as potential precision oncology collateral lethality targets (PANK1 is co-deleted as part of the PTEN locus in some highly aggressive cancers) were severely hindered by a dearth of commercial antibodies that can reliably detect endogenous PANK3 protein. While we successfully validated commercial antibodies for PANK1 and PANK2 using CRISPR knockout cell lines, we found no commercial antibody that could detect endogenous PANK3. We therefore set out to generate a mouse monoclonal antibody against human PANK3 protein. We demonstrate that a clone (Clone MDA-299-62A) can reliably detect endogenous PANK3 protein in cancer cell lines, with band-specificity confirmed by CRISPR PANK3 knockout and knockdown cell lines. Sub-cellular fractionation shows that PANK3 is overwhelmingly cytosolic and expressed broadly across cancer cell lines. PANK3 monoclonal antibody MDA-299-62A should prove a valuable tool for researchers investigating this understudied family of metabolic enzymes in health and disease.

Manipulation of pantothenate kinase in Anopheles stephensi suppresses pantothenate levels with minimal impacts on mosquito fitness

Pantothenate (Pan) is an essential nutrient required by both the mosquito vector and malaria parasite. We previously demonstrated that increasing pantothenate kinase (PanK) activity and co-enzyme A (CoA) biosynthesis led to significantly decreased parasite infection prevalence and intensity in the malaria mosquito Anopheles stephensi. In this study, we demonstrate that Pan stores in A. stephensi are a limited resource and that manipulation of PanK levels or activity, via small molecule modulators of PanK or transgenic mosquitoes, leads to the conversion of Pan to CoA and an overall reduction in Pan levels with minimal to no effects on mosquito fitness. Transgenic A. stephensi lines with repressed insulin signaling due to PTEN overexpression or repressed c-Jun N-terminal kinase (JNK) signaling due to MAPK phosphatase 4 (MKP4) overexpression exhibited enhanced PanK levels and significant reductions in Pan relative to non-transgenic controls, with the PTEN line also exhibiting significantly increased CoA levels. Provisioning of the PTEN line with the small molecule PanK modulator PZ-2891 increased CoA levels while provisioning Compound 7 decreased CoA levels, affirming chemical manipulation of mosquito PanK. We assessed effects of these small molecules on A. stephensi lifespan, reproduction and metabolism under optimized laboratory conditions. PZ-2891 and Compound 7 had no impact on A. stephensi survival when delivered via bloodmeal throughout mosquito lifespan. Further, PZ-2891 provisioning had no impact on egg production over the first two reproductive cycles. Finally, PanK manipulation with small molecules was associated with minimal impacts on nutritional stores in A. stephensi mosquitoes under optimized rearing conditions. Together with our previous data demonstrating that PanK activation was associated with significantly increased A. stephensi resistance to Plasmodium falciparum infection, the studies herein demonstrate a lack of fitness costs of mosquito Pan depletion as a basis for a feasible, novel strategy to control parasite infection of anopheline mosquitoes.

Genetic Characterisation of Pantothenate Kinase Associated Neurodegeneration (PKAN) in a Consanguineous Family from Jammu and Kashmir India

Pantothenate kinase-associated neurodegeneration (PKAN), a rare neurological disorder occurs by variation(s) in the PANK2 (Pantothenate kinase 2) gene and is linked to iron accumulation in the basal ganglia. The researchers have carried out targeted gene sequencing of all exons of PANK2 in a patient with suspected phenotype of PKAN. A missense variant in exon 6 of PANK2 gene (NM_153638.3:c.1583C>T,NP_705902.2:p.Thr528Met) has been identified in the patient. Further, sequencing of the exon in extended consanguineous family showed autosomal recessive mode of inheritance in the family. It is emphasised that inclusion of molecular diagnostics in clinical evaluation procedures of potential genetic or uncharacterised abnormalities is critical especially if the family has known history of high consanguinity. It is anticipated to provide effectively, such families with access to a variety of genetic counselling programmes, thus reducing illness burden in the affected family.

Amodiaquine drug pressure selects nonsynonymous mutations in pantothenate kinase 1, diacylglycerol kinase, and phosphatidylinositol-4 kinase in Plasmodium berghei ANKA.

Lumefantrine (LM), piperaquine (PQ), and amodiaquine (AQ), the long-acting components of the artemisinin-based combination therapies (ACTs), are a cornerstone of malaria treatment in Africa. Studies have shown that PQ, AQ, and LM resistance may arise independently of predicted modes of action. Protein kinases have emerged as mediators of drug action and efficacy in malaria parasites; however, the link between top druggable Plasmodium kinases with LM, PQ, and AQ resistance remains unclear. Using LM, PQ, or AQ-resistant Plasmodium berghei parasites, we have evaluated the association of choline kinase (CK), pantothenate kinase 1 (PANK1), diacylglycerol kinase (DAGK), and phosphatidylinositol-4 kinase (PI4Kβ), and calcium-dependent protein kinase 1 (CDPK1) with LM, PQ, and AQ resistance in Plasmodium berghei ANKA. We used in silico bioinformatics tools to identify ligand-binding motifs, active sites, and sequence conservation across the different parasites. We then used PCR and sequencing analysis to probe for single nucleotide polymorphisms (SNPs) within the predicted functional motifs in the CK, PANK1, DAGK, PI4Kβ, and CDPK1. Using qPCR analysis, we measured the mRNA amount of PANK1, DAGK, and PI4Kβ at trophozoites and schizonts stages. We reveal sequence conservation and unique ligand-binding motifs in the CK, PANK1, DAGK, PI4Kβ, and CDPK1 across malaria species. DAGK, PANK1, and PI4Kβ possessed nonsynonymous mutations; surprisingly, the mutations only occurred in the AQr parasites. PANK1 acquired Asn394His, while DAGK contained K270R and K292R mutations. PI4Kβ had Asp366Asn, Ser1367Arg, Tyr1394Asn and Asp1423Asn. We show downregulation of PANK1, DAGK, and PI4Kβ in the trophozoites but upregulation at the schizonts stages in the AQr parasites. The selective acquisition of the mutations and the differential gene expression in AQ-resistant parasites may signify proteins under AQ pressure. The role of the mutations in the resistant parasites and their impact on drug responses require investigations using reverse genetics techniques in malaria parasites.

Therapeutic approach with commercial supplements for pantothenate kinase-associated neurodegeneration with residual PANK2 expression levels

BackgroundNeurodegeneration with brain iron accumulation (NBIA) is a group of rare neurogenetic disorders frequently associated with iron accumulation in the basal nuclei of the brain characterized by progressive spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration or optic nerve atrophy. Pantothenate kinase-associated neurodegeneration (PKAN) is one of the most widespread NBIA subtypes. It is caused by mutations in the gene of pantothenate kinase 2 (PANK2) that result in dysfunction in PANK2 enzyme activity, with consequent deficiency of coenzyme A (CoA) biosynthesis, as well as low levels of essential metabolic intermediates such as 4′-phosphopantetheine, a necessary cofactor for essential cytosolic and mitochondrial proteins.MethodsIn this manuscript, we examined the therapeutic effectiveness of pantothenate, panthetine, antioxidants (vitamin E and omega 3) and mitochondrial function boosting supplements (L-carnitine and thiamine) in mutant PANK2 cells with residual expression levels.ResultsCommercial supplements, pantothenate, pantethine, vitamin E, omega 3, carnitine and thiamine were able to eliminate iron accumulation, increase PANK2, mtACP, and NFS1 expression levels and improve pathological alterations in mutant cells with residual PANK2 expression levels.ConclusionOur results suggest that several commercial compounds are indeed able to significantly correct the mutant phenotype in cellular models of PKAN. These compounds alone or in combinations are of common use in clinical practice and may be useful for the treatment of PKAN patients with residual enzyme expression levels.

Long-Term Neuroradiological and Clinical Evaluation of NBIA Patients Treated with a Deferiprone Based Iron-Chelation Therapy.

Neurodegeneration with brain iron accumulation (NBIA) comprises various rare clinical entities with brain iron overload as a common feature. Magnetic resonance imaging (MRI) allows diagnosis of this condition, and genetic molecular testing can confirm the diagnosis to better understand the intracellular damage mechanism involved. NBIA groups disorders include: pantothenate kinase-associated neurodegeneration (PKAN), mutations in the gene encoding pantothenate kinase 2 (PANK2); neuroferritinopathy, mutations in the calcium-independent phospholipase A2 gene (PLA2G6); aceruloplasminemia; and other subtypes with no specific clinical or MRI specific patterns identified. There is no causal therapy, and only symptom treatments are available for this condition. Promising strategies include the use of deferiprone (DFP), an orally administered bidentate iron chelator with the ability to pass through the blood–brain barrier. This is a prospective study analysis with a mean follow-up time of 5.5 ± 2.3 years (min–max: 2.4–9.6 years) to define DFP (15 mg/kg bid)’s efficacy and safety in the continuous treatment of 10 NBIA patients through clinical and neuroradiological evaluation. Our results show the progressive decrease in the cerebral accumulation of iron evaluated by MRI and a substantial stability of the overall clinical neurological picture without a significant correlation between clinical and radiological findings. Complete ferrochelation throughout the day appears to be of fundamental importance considering that oxidative damage is generated, above, all by non-transferrin-bound iron (NTBI); thus, we hypothesize that a (TID) administration regimen of DFP might better apply its chelating properties over 24 h with the aim to also obtain clinical improvement beyond the neuroradiological improvement.

PI3K drives the de novo synthesis of coenzyme A from vitamin B5

In response to hormones and growth factors, the class I phosphoinositide-3-kinase (PI3K) signalling network functions as a major regulator of metabolism and growth, governing cellular nutrient uptake, energy generation, reducing cofactor production and macromolecule biosynthesis1. Many of the driver mutations in cancer with the highest recurrence, including in receptor tyrosine kinases, Ras, PTEN and PI3K, pathologically activate PI3K signalling2,3. However, our understanding of the core metabolic program controlled by PI3K is almost certainly incomplete. Here, using mass-spectrometry-based metabolomics and isotope tracing, we show that PI3K signalling stimulates the de novo synthesis of one of the most pivotal metabolic cofactors: coenzyme A (CoA). CoA is the major carrier of activated acyl groups in cells4,5 and is synthesized from cysteine, ATP and the essential nutrient vitamin B5 (also known as pantothenate)6,7. We identify pantothenate kinase 2 (PANK2) and PANK4 as substrates of the PI3K effector kinase AKT8. Although PANK2 is known to catalyse the rate-determining first step of CoA synthesis, we find that the minimally characterized but highly conserved PANK49 is a rate-limiting suppressor of CoA synthesis through its metabolite phosphatase activity. Phosphorylation of PANK4 by AKT relieves this suppression. Ultimately, the PI3K–PANK4 axis regulates the abundance of acetyl-CoA and other acyl-CoAs, CoA-dependent processes such as lipid metabolism and proliferation. We propose that these regulatory mechanisms coordinate cellular CoA supplies with the demands of hormone/growth-factor-driven or oncogene-driven metabolism and growth.

Fatty Acid Production by Enhanced Malonyl-CoA Supply in Escherichia coli

The expression of exogenous genes encoding acetyl-CoA carboxylase (Acc) and pantothenate kinase (CoaA) in Escherichia coli enable highly effective fatty acid production. Acc-only strains grown at 37°C or 23°C produced an approximately twofold increase in fatty acid content, and additional expression of CoaA achieved a further twofold accumulation. In the presence of pantothenate, which is the starting material for the CoA biosynthetic pathway, the size of the intracellular CoA pool at 23°C was comparable to that at 30°C during cultivation, and more than 500mg/L of culture containing cellular fatty acids was produced, even at 23°C. However, the highest yield of cellular fatty acids (1100mg/L of culture) was produced in cells possessing the gene encoding type I bacterial fatty acid synthase (FasA) along with the acc and coaA, when the transformant was cultivated at 30°C in M9 minimal salt medium without pantothenate or IPTG. This E. coli transformant contained 141mg/L of oleic acid attributed to FasA under noninducible conditions. The increased fatty acid content was brought about by a greatly improved specific productivity of 289mg/g of dry cell weight. Thus, the effectiveness of the foreign acc and coaA in fatty acid production was unambiguously confirmed at culture temperatures of 23°C to 37°C. Cofactor engineering in E. coli using the exogenous coaA and acc genes resulted in fatty acid production over 1g/L of culture and could effectively function at 23°C.

PKAN hiPS-Derived Astrocytes Show Impairment of Endosomal Trafficking: A Potential Mechanism Underlying Iron Accumulation.

PKAN disease is caused by mutations in the PANK2 gene, encoding the mitochondrial enzyme pantothenate kinase 2, catalyzing the first and key reaction in Coenzyme A (CoA) biosynthetic process. This disorder is characterized by progressive neurodegeneration and excessive iron deposition in the brain. The pathogenic mechanisms of PKAN are still unclear, and the available therapies are only symptomatic. Although iron accumulation is a hallmark of PKAN, its relationship with CoA dysfunction is not clear. We have previously developed hiPS-derived astrocytes from PKAN patients showing iron overload, thus recapitulating the human phenotype. In this work, we demonstrated that PKAN astrocytes presented an increase in transferrin uptake, a key route for cellular iron intake via transferrin receptor-mediated endocytosis of transferrin-bound iron. Investigation of constitutive exo-endocytosis and vesicular dynamics, exploiting the activity-enriching biosensor SynaptoZip, led to the finding of a general impairment in the constitutive endosomal trafficking in PKAN astrocytes. CoA and 4-phenylbutyric acid treatments were found to be effective in partially rescuing the aberrant vesicular behavior and iron intake. Our results demonstrate that the impairment of CoA biosynthesis could interfere with pivotal intracellular mechanisms involved in membrane fusions and vesicular trafficking, leading to an aberrant transferrin receptor-mediated iron uptake.

Intrathecal baclofen therapy as treatment for spasticity and dystonia: Review of cases in a pediatric palliative care unit

IntroductionPatients managed in the Pediatric Palliative Care Integral Unit (PPCIU) have serious neurological conditions that involve significant damage at central nervous system level. The movement disorder is a very common clinical problem and for the patients where an adequate control of muscle tone is not achieved with usual techniques or drugs, intrathecal baclofen therapy (IBT) should be considered. Materials and methodsDescriptive retrospective study based on the review of clinical records of patients who received IBT being followed by the PPCIU of Madrid Autonomous Region in the timeframe between September 2012 and February 2021. ResultsIBT was implanted in 8 patients affected by infantile cerebral palsy (ICP) with a Gross Motor Function Scale (GMFCS) IV–V, 3 patients was a Pantothenate kinase deficit-associated neurodegeneration (PKAN), 2 had Acquired Brain Damage, and the remaining 3 had, respectively, 2 glutaric aciduria type I (GA-1), and poly-malformative syndrome. In all patients we observed a period of clinical stability after IBT, we call this period “honeymoon”. Two patients died while in the honeymoon period, at 24.9 and 19.6 months from implantation of the pump; the median of duration of the honeymoon period in the remaining 14 was 14.4 months (IQ: 8.3–25.8). ConclusionsIBT was not only used in patients with non-progressive diseases, but also in the group of patients with neurodegenerative or progressive diseases. In all of them, after implantation of the device, we have objectified a period of clinical stability and a better control of muscle tone disorders.

Type 1 neurodegeneration with brain iron accumulation: a case report

BackgroundType 1 neurodegeneration with brain iron accumulation is a rare neurological disorder with estimated prevalence of one to two per million persons worldwide, characterized by progressive degeneration of basal ganglia, globus pallidus, and reticular part of substantia nigra, produced by brain iron accumulation due to a defect in the gene producing pantothenate kinase 2. Clinical presentations include dystonia, dysarthria, dysphagia, dementia, severe mental retardation, and severe movement disability at later stages. The characteristic pattern on brain magnetic resonance imaging shows the “eye of the tiger” sign. Treatment in late stages is mainly symptomatic. We report the case of a Cuban boy with high-severity brain iron accumulation, with positive clinical and imaging findings diagnosed in a late stage of the illness. This degree of severity has never been reported in Cuba and is rarely reported worldwide.Case presentationWe present the case of a 19-year-old male white Cuban boy who presented to our department with features of spasticity, dystonia, gait difficulty, dysarthria, dysphagia, aggressiveness, and sleep disorders. He was diagnosed with pantothenate kinase-associated neurodegeneration on the basis of clinical findings and typical “eye of the tiger” pattern on brain magnetic resonance imaging. Detailed evaluation was carried out, and symptomatic treatment and physiotherapy were started with trihexyphenidyl, cabergoline, baclofen, and intramuscular botulinum neurotoxin as well as daily home sessions of passive stretching, weight bearing, and muscle massaging. At 3 months reevaluation, the patient showed a great improvement of motor function, with a decrease of dystonic symptoms, although language, cognition, and functional independence showed no improvement. The prognosis of the patient remains reserved.ConclusionThe diagnosis can be made based on the presence of clinical and imaging features. The presence of “eye-of-the-tiger” sign on magnetic resonance imaging must be considered a nearly pathognomonic sign of neurodegeneration with brain iron accumulation presence. Treatment after high-severity presentation remains directed toward symptomatic findings. Both dopamine agonists and anticholinergic agents are useful to treat motor symptoms, but there is not yet an effective treatment to stop the underlying degeneration. New therapeutic approaches are needed to counteract late stages of the disease and improve prognosis.

Multi-ancestry genome-wide association study of asthma exacerbations.

Asthma exacerbations are a serious public health concern due to high healthcare resource utilization, work/school productivity loss, impact on quality of life, and risk of mortality. The genetic basis of asthma exacerbations has been studied in several populations, but no prior study has performed a multi-ancestry meta-analysis of genome-wide association studies (meta-GWAS) for this trait. We aimed to identify common genetic loci associated with asthma exacerbations across diverse populations and to assess their functional role in regulating DNA methylation and gene expression. A meta-GWAS of asthma exacerbations in 4989 Europeans, 2181 Hispanics/Latinos, 1250 Singaporean Chinese, and 972 African Americans analyzed 9.6million genetic variants. Suggestively associated variants (p≤5×10-5 ) were assessed for replication in 36,477 European and 1078 non-European asthma patients. Functional effects on DNA methylation were assessed in 595 Hispanic/Latino and African American asthma patients and in publicly available databases. The effect on gene expression was evaluated in silico. One hundred and twenty-six independent variants were suggestively associated with asthma exacerbations in the discovery phase. Two variants independently replicated: rs12091010located atvascular cell adhesion molecule-1/exostosin likeglycosyltransferase-2 (VCAM1/EXTL2)(discovery: odds ratio (ORT allele )=0.82, p=9.05×10-6 and replication: ORT allele =0.89, p=5.35×10-3 ) and rs943126 frompantothenate kinase1 (PANK1) (discovery: ORC allele =0.85, p=3.10×10-5 and replication: ORC allele =0.89, p=1.30×10-2 ). Both variants regulate gene expressionof genes where they locate and DNA methylation levels of nearby genes in whole blood. This multi-ancestry study revealed novel suggestive regulatory loci for asthma exacerbations located in genomic regions participating in inflammation and host defense.

Pantothenate kinase 2 interacts with PINK1 to regulate mitochondrial quality control via acetyl-CoA metabolism

Human neurodegenerative disorders often exhibit similar pathologies, suggesting a shared aetiology. Key pathological features of Parkinson’s disease (PD) are also observed in other neurodegenerative diseases. Pantothenate Kinase-Associated Neurodegeneration (PKAN) is caused by mutations in the human PANK2 gene, which catalyzes the initial step of de novo CoA synthesis. Here, we show that fumble (fbl), the human PANK2 homolog in Drosophila, interacts with PINK1 genetically. fbl and PINK1 mutants display similar mitochondrial abnormalities, and overexpression of mitochondrial Fbl rescues PINK1 loss-of-function (LOF) defects. Dietary vitamin B5 derivatives effectively rescue CoA/acetyl-CoA levels and mitochondrial function, reversing the PINK1 deficiency phenotype. Mechanistically, Fbl regulates Ref(2)P (p62/SQSTM1 homolog) by acetylation to promote mitophagy, whereas PINK1 regulates fbl translation by anchoring mRNA molecules to the outer mitochondrial membrane. In conclusion, Fbl (or PANK2) acts downstream of PINK1, regulating CoA/acetyl-CoA metabolism to promote mitophagy, uncovering a potential therapeutic intervention strategy in PD treatment.

Circ-Pank1 promotes dopaminergic neuron neurodegeneration through modulating miR-7a-5p/α-syn pathway in Parkinson’s disease

Circular RNA (circRNA) is a type of non-coding RNA that is widely expressed in mammals. It is highly conserved and abundantly expressed in the brain. Here, we report the regulatory role of circRNA derived from the pantothenate kinase 1 (Pank1) gene (circ-Pank1) in Parkinson’s disease (PD). Circ-Pank1 is highly expressed in the substantia nigra (SN) of PD model mice treated with rotenone and in the MN9D cell model of dopaminergic neurons. The circ-Pank1 knockdown ameliorated dopaminergic neuron damage and locomotor dysfunction after the treatment with rotenone. We found that circ-Pank1 could adsorb miR-7a-5p and upregulate the expression of α-synuclein (α-syn), which is a molecular hallmark closely related to PD. The inhibition of miR-7a-5p reversed the circ-Pank1 knockdown-induced amelioration of dopaminergic neuron injury. In conclusion, circ-Pank1 is overexpressed in PD and enhances the locomotor dysfunction via the miR-7a-5p/α-syn signaling axis. We revealed the functional role of circRNAs in the progression of PD and provided a potential target for noncoding RNAs in delaying the progression of PD.

Targeting Pantothenate Kinase as an Effective Strategy for Antifungal Drug Development

Fungal infections affect over one billion people worldwide each year and are the leading cause of mortality by eukaryotic pathogens with an estimated 150 million severe life‐threatening cases and 1.7 million deaths reported annually. The rapid increase in the number of clinical cases and the emergence of multidrug resistant pathogens such as Candida auris emphasize the urgent need for new strategies to develop more effective, selective and safe antifungals. Coenzyme A (CoA) plays a central role in key cellular processes including the citric acid cycle, lipid metabolism, and ergosterol biosynthesis. The first step in the CoA biosynthesis pathway is catalyzed by a pantothenate kinase (PanK), which phosphorylates pantothenic acid (PA, or vitamin B5) to form phosphopantothenate. In fungi, this enzyme is encoded by a single copy PanK gene, which plays an essential role in cell viability. Here, we report the first crystal structure of the S. cerevisiae PanK enzyme, Cab1, at 1.8Å resolution. Cab1 was crystallized alone and in the presence of three lead high‐affinity inhibitors identified in a high‐throughput chemical screen of a library of 156,593 small molecules. Structure‐guided mutagenesis together with functional complementation assays in yeast identified key residues in Cab1 that are essential for catalysis, substrate binding and dimerization. Structure activity relationship and biological assays identified a lead inhibitor YU385599, with excellent activity against the human pathogens Candida albicans, C. glabrata, and C. parapsilosis. Together, our data validate PanK activity as a novel drug target and identify a novel class of small molecules for the treatment of fungal diseases.