Mevalonate Kinase Research Articles

Mevalonate kinase deficiency: an updated clinical overview and revision of the SHARE recommendations

Mevalonate kinase deficiency (MKD), a rare auto-inflammatory disorder, arises from mutations in the MVK gene, disrupting isoprenoid biosynthesis, and affecting cellular processes. This comprehensive review provides an updated perspective on MKD, including its aetiology, pathogenesis, diagnostic modalities, and therapeutic strategies. Based on recent research and clinical advances, our objective is to bridge the knowledge gaps in the 2015 SHARE guidelines. By describing molecular mechanisms, diagnostic dilemmas, and emerging therapies, this article should serve as a resource for clinicians and researchers, promoting a deeper understanding of MKD and guiding optimal patient care.

IL-6R (trans-signaling) is a key regulator of reverse cholesterol transport in lipid-laden macrophages

Atherosclerosis is a cardiovascular disease caused by cholesterol-laden arterial plaques. This study evaluated the correlation between interleukin-6 (IL-6), its receptors (IL6R/CD126), and glycoprotein 130 (gp130) alongside atherosclerosis biomarkers in a cohort of 142 subjects, equally divided between lean and obese individuals. Subsequent analyses used THP-1-derived macrophages to assess the biochemical impact of inhibiting IL-6 receptors. IL-6 secretion increased with atherosclerosis in obese subjects, while IL6R/CD126 and gp130 on monocytes decreased. Pharmacological gp130 inhibition altered lipid metabolism, increasing LDLR gene expression and cholesterol synthesis via SREBF2 and mevalonate kinase, along with HMG-CoA reductase at protein levels. gp130-deficient cells produced more cholesterol and had lower ABCA1 levels, suggesting hindered cholesterol efflux. Filipin III staining confirmed cholesterol retention in gp130-inhibited cells. Ex-vivo investigation on lean PBMCs further defined the impact of gp130 inhibition on the reduction of cholesterol efflux. Our results indicates gp130 is crucial for macrophage reverse cholesterol transport and may be a target for atherosclerosis treatments.

Mevalonate kinase of Leishmania donovani promotes its survival and plays a pivotal role in pathogenesis

The infectivity of Leishmania is determined by its ability to invade and evade host and its thriving capacity within the macrophage. Our study revealed the role of Leishmania donovani mevalonate kinase (MVK), an enzyme of mevalonate pathway in visceral leishmaniasis pathogenesis. Peritoneal exudate cells (PEC)-derived macrophages from BALB/c mice were infected with wild type (WT), MVK over expressing (MVK OE) and knockdown (KD) parasites and MVK OE parasites were found to be more infective than WT and MVK KD parasites. Incubation of macrophages with MVK OE parasites declined inducible nitric oxide synthase (iNOS) expression as well as nitric oxide (NO) production, both by 2 times in comparison to WT parasites. Moreover, ∼3 fold increase in Arginase1 expression indicated that MVK might induce polarization of macrophage towards M2, favouring the survival of parasite within the macrophages. Post 24 h infection of the macrophages with mutant strains, the levels of different cytokines (TNF-α, IL-12, IL-10 and IFN-γ) were measured. Infection of macrophages with MVK OE parasites showed an increase in the level of anti-inflammatory cytokine: IL-10 while infection with MVK KD parasites exhibited an increase in the level of pro-inflammatory cytokines: TNF-α, IL-12, and IFN-γ. Hence, Leishmania donovani mevalonate kinase (LdMVK) modulates macrophage functions and has a significant role in pathogenesis.

Glucose-oxygen deprivation constrains HMGCR function and Rac1 prenylation and activates the NLRP3 inflammasome in human monocytes.

Hypoxia and low glucose abundance often occur simultaneously at sites of inflammation. In monocytes and macrophages, glucose-oxygen deprivation stimulates the assembly of the NLRP3 inflammasome to generate the proinflammatory cytokine IL-1β. We found that concomitant glucose deprivation and hypoxia activated the NLRP3 inflammasome by constraining the function of HMG-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate kinase pathway. HMGCR is involved in the synthesis of geranylgeranyl pyrophosphate (GGPP), which is required for the prenylation and lipid membrane integration of proteins. Under glucose-oxygen deprivation, GGPP synthesis was decreased, leading to reduced prenylation of the small GTPase Rac1, increased binding of nonprenylated Rac1 to the scaffolding protein IQGAP1, and enhanced activation of the NLRP3 inflammasome. In response to restricted oxygen and glucose supply, patient monocytes with a compromised mevalonate pathway due to mevalonate kinase deficiency or Muckle-Wells syndrome released more IL-1β than did control monocytes. Thus, reduced GGPP synthesis due to inhibition of HMGCR under glucose-oxygen deprivation results in proinflammatory innate responses, which are normally kept in check by the prenylation of Rac1. We suggest that this mechanism is also active in inflammatory autoimmune conditions.

EST-SSR Mining and Characterization from Aquilaria malaccensis Transcriptome Shotgun Assembly

Aquilaria malaccensis is a member of Thymelaceae family which is one of the main trees producing agarwood compounds in Indonesia and has high economic value. A. malaccensis has Appendix II conservation status due to high exploitation in the nature. One of the several efforts to maintain agarwood production while also maintaining agarwood population is efficient induction by manipulation of the pathway for agarwood formation and using individuals with higher production of agarwood compounds. Selection of superior individuals can be done using molecular markers that are linked to certain genes, including microsatellites or simple sequence repeats (SSR). This study aimed to identify SSRs in the agarwood transcriptome and characterized SSR sites that are linked to genes involved in the synthesis of agarwood compounds. The transcriptome data used was extracted from the NCBI database with accession number GHJS00000000.1. SSR mining was carried out using Krait v.1.4.0 software, then BLASTed with the protein database to analyze the linkage with the related genes. Perfect SSRs were found in 0.37% of the total sequences, and compound SSRs were 10.89%. The abundance of imperfect SSR (107,043) was greater than perfect SSR (31,262), indicating that SSR in the transcriptome had a low mutation rate and the SSR site was more conserved in A. malaccensis. The SSRs that linked to genes related to agarwood synthesis including HMGR, PAL, Mevalonate Kinase, MAPK, Delta-guaiene synthase, Farnesyl pyrophosphate synthase, and Phenylalanine ammonia-lyase. The discovery of SSRs linked to these genes can be used to create molecular markers that can be applied in agarwood producing trees selection.

Transcriptomic and free monoterpene analyses of aroma reveal that isopentenyl diphosphate isomerase inhibits monoterpene biosynthesis in grape (Vitis vinifera L.)

BackgroundMonoterpenes are among the most important volatile aromatic compounds contributing to the flavor and aroma of grapes and wine. However, the molecular basis of monoterpene biosynthesis has not yet been fully elucidated.ResultsIn our study, transcriptomics and gas chromatography-mass spectrometry (GC-MS) were used to mine candidate genes and transcription factors involved in monoterpene biosynthesis between high-monoterpene and zero-monoterpene table grape cultivars. We found that monoterpene biosynthesis was positively correlated by the expression of five genes encoding 1-deoxy-D-xylulose-5-phosphate synthase (VvDXSs), one encoding 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (VvHDR), three hydroxy-3-methylglutaryl-CoA synthases (VvHMGSs) and one mevalonate kinase (VvMVK), whereas the expression of one isopentenyl diphosphate isomerase (VvIDI) and one 3-hydroxy-3-methylglutaryl-CoA reductase (VvHMGR) negatively correlated monoterpene biosynthesis. Of these genes, VvIDI was selected to validate its function in monoterpene accumulation through a transient overexpression experiment, and was shown to inhibit the biosynthesis of grape linalool and α-terpineol. Meanwhile, we found that a 64-amino acid extension sequence at the N-terminus can guide the VvIDI protein to target the chloroplast.ConclusionsThe findings of this study should help to guide future functional analysis of key genes as well as mining the potential regulatory mechanism of monoterpene biosynthesis in grapes and grape products.

Inhibition of human mevalonate kinase by allosteric inhibitors of farnesyl pyrophosphate synthase.

Mevalonate kinase is a key regulator of the mevalonate pathway, subject to feedback inhibition by the downstream metabolite farnesyl pyrophosphate. In this study, we validated the hypothesis that monophosphonate compounds mimicking farnesyl pyrophosphate can inhibit mevalonate kinase. Exploring compounds originally synthesized as allosteric inhibitors of farnesyl pyrophosphate synthase, we discovered mevalonate kinase inhibitors with nanomolar activity. Kinetic characterization of the two most potent inhibitors demonstrated Ki values of 3.1 and 22 nm. Structural comparison suggested features of these inhibitors likely responsible for their potency. Our findings introduce the first class of nanomolar inhibitors of human mevalonate kinase, opening avenues for future research. These compounds might prove useful as molecular tools to study mevalonate pathway regulation and evaluate mevalonate kinase as a potential therapeutic target.

Enhancement of production of glycoalkaloids by elicitors along with characterization of gene expression of pathways in Solanum xanthocarpum

Solanum xanthocarpum fruits are used in the treatment of cough, fever, and heart disorders. It possesses antipyretic, hypotensive, antiasthmatic, aphrodisiac and antianaphylactic properties. In the present study, 24 elicitors (both biotic and abiotic) were used to enhance the production of glycoalkaloids in cell cultures of S. xanthocarpum. Four concentrations of elicitors were added into the MS culture medium. The maximum accumulation (5.56-fold higher than control) of demissidine was induced by sodium nitroprusside at 50 mM concentration whereas the highest growth of cell biomass (4.51-fold higher than control) stimulated by systemin at 30 mM concentration. A total of 17 genes of biosynthetic pathways of glycoalkaloids were characterized from the cells of S. xanthocarpum. The greater accumulation of demissidine was confirmed with the expression analysis of 11 key biosynthetic pathway enzymes e.g., acetoacetic-CoA thiolase, 3- hydroxy 3-methyl glutaryl synthase, β-hydroxy β-methylglutaryl CoA reductase, mevalonate kinase, farnesyl diphosphate synthase, squalene synthase, squalene epoxidase, squalene-2,3- epoxide cyclase, cycloartenol synthase, UDP-glucose: solanidine glucosyltransferase and UDP-rhamnose: solanidine rhamno-galactosyl transferase. The maximum expression levels of UDP-rhamnose: solanidine rhamno-galactosyl transferase gene was recorded in this study.

Molecular and cellular consequences of mevalonate kinase deficiency

Mevalonate kinase deficiency (MKD) is an autosomal recessive metabolic disorder associated with recurrent autoinflammatory episodes. The disorder is caused by bi-allelic loss-of-function variants in the MVK gene, which encodes mevalonate kinase (MK), an early enzyme in the isoprenoid biosynthesis pathway. To identify molecular and cellular consequences of MKD, we studied primary fibroblasts from severely affected patients with mevalonic aciduria (MKD-MA) and more mildly affected patients with hyper IgD and periodic fever syndrome (MKD-HIDS). As previous findings indicated that the deficient MK activity in MKD impacts protein prenylation in a temperature-sensitive manner, we compared the subcellular localization and activation of the small Rho GTPases RhoA, Rac1 and Cdc42 in control, MKD-HIDS and MKD-MA fibroblasts cultured at physiological and elevated temperatures. This revealed a temperature-induced altered subcellular localization and activation in the MKD cells. To study if and how the temperature-induced ectopic activation of these signalling proteins affects cellular processes, we performed comparative transcriptome analysis of control and MKD-MA fibroblasts cultured at 37 °C or 40 °C. This identified cell cycle and actin cytoskeleton organization as respectively most down- and upregulated gene clusters. Further studies confirmed that these processes were affected in fibroblasts from both patients with MKD-MA and MKD-HIDS. Finally, we found that, similar to immune cells, the MK deficiency causes metabolic reprogramming in MKD fibroblasts resulting in increased expression of genes involved in glycolysis and the PI3K/Akt/mTOR pathway. We postulate that the ectopic activation of small GTPases causes inappropriate signalling contributing to the molecular and cellular aberrations observed in MKD.

Canakinumab treatment real world evidence in 3 monogenic periodic fever syndromes in 2009–2022: an interim analysis using the French JIR cohort database

BackgroundOur study aimed to provide real-world evidence on the treatment patterns, effectiveness and safety of canakinumab in France in Familial Mediterranean Fever (FMF), Mevalonate Kinase Deficiency (MKD), and Tumor necrosis factor Receptor Associated Periodic Syndrome (TRAPS).MethodsThis study used the JIR cohort, a multicentre international registry created in 2013 to collect data on patients with juvenile inflammatory rheumatic diseases. French patients diagnosed with FMF, MKD or TRAPS and treated with canakinumab were included in this study.Results31 FMF, 26 MKD and 7 TRAPS patients received canakinumab during the study period. Most of them initiated canakinumab at the recommended dose of 2 mg/kg or 150 mg, but less than half of FMF and MKD patients initiated it at the recommended frequency (every 4 weeks). Two years after initiation, the rate of patients still on treatment was 78.1% in FMF, 73.7% in MKD, and 85.7% in TRAPS patients. While the dose per injection remained globally the same over the course of the treatment, some adjustments of the dose intervals were observed. Six patients had a severe adverse event reported. Of those, three were possibly related to canakinumab.ConclusionThis interim analysis showed a good maintenance of canakinumab treatment 2 years after initiation and confirmed its safety profile in real-life practice in France in patients diagnosed with FMF, MKD and TRAPS. The high variety of dose and interval combinations observed in canakinumab treated patients let suppose that physicians adapt the posology to individual situations rather than a fixed treatment plan.

Mevalonate kinase-deficient THP-1 cells show a disease-characteristic pro-inflammatory phenotype.

Bi-allelic pathogenic variants in the MVK gene, which encodes mevalonate kinase (MK), an essential enzyme in isoprenoid biosynthesis, cause the autoinflammatory metabolic disorder mevalonate kinase deficiency (MKD). We generated and characterized MK-deficient monocytic THP-1 cells to identify molecular and cellular mechanisms that contribute to the pro-inflammatory phenotype of MKD. Using CRISPR/Cas9 genome editing, we generated THP-1 cells with different MK deficiencies mimicking the severe (MKD-MA) and mild end (MKD-HIDS) of the MKD disease spectrum. Following confirmation of previously established disease-specific biochemical hallmarks, we studied the consequences of the different MK deficiencies on LPS-stimulated cytokine release, glycolysis versus oxidative phosphorylation rates, cellular chemotaxis and protein kinase activity. Similar to MKD patients' cells, MK deficiency in the THP-1 cells caused a pro-inflammatory phenotype with a severity correlating with the residual MK protein levels. In the MKD-MA THP-1 cells, MK protein levels were barely detectable, which affected protein prenylation and was accompanied by a profound pro-inflammatory phenotype. This included a markedly increased LPS-stimulated release of pro-inflammatory cytokines and a metabolic switch from oxidative phosphorylation towards glycolysis. We also observed increased activity of protein kinases that are involved in cell migration and proliferation, and in innate and adaptive immune responses. The MKD-HIDS THP-1 cells had approximately 20% residual MK activity and showed a milder phenotype, which manifested mainly upon LPS stimulation or exposure to elevated temperatures. MK-deficient THP-1 cells show the biochemical and pro-inflammatory phenotype of MKD and are a good model to study underlying disease mechanisms and therapeutic options of this autoinflammatory disorder.

Characterization of novel mevalonate kinases from the tardigrade Ramazzottius varieornatus and the psychrophilic archaeon Methanococcoides burtonii.

Mevalonate kinase is central to the isoprenoid biosynthesis pathway. Here, high-resolution X-ray crystal structures of two mevalonate kinases are presented: a eukaryotic protein from Ramazzottius varieornatus and an archaeal protein from Methanococcoides burtonii. Both enzymes possess the highly conserved motifs of the GHMP enzyme superfamily, with notable differences between the two enzymes in the N-terminal part of the structures. Biochemical characterization of the two enzymes revealed major differences in their sensitivity to geranyl pyrophosphate and farnesyl pyrophosphate, and in their thermal stabilities. This work adds to the understanding of the structural basis of enzyme inhibition and thermostability in mevalonate kinases.

Structural Characterization and Functional Analysis of Mevalonate Kinase from Tribolium castaneum (Red Flour Beetle).

Mevalonate kinase (MevK) is an important enzyme in the mevalonate pathway that catalyzes the phosphorylation of mevalonate into phosphomevalonate and is involved in juvenile hormone biosynthesis. Herein, we present a structure model of MevK from the red flour beetle Tribolium castaneum (TcMevK), which adopts a compact α/β conformation that can be divided into two parts: an N-terminal domain and a C-terminal domain. A narrow, deep cavity accommodating the substrate and cofactor was observed at the junction between the two domains of TcMevK. Computational simulation combined with site-directed mutagenesis and biochemical analyses allowed us to define the binding mode of TcMevK to cofactors and substrates. Moreover, TcMevK showed optimal enzyme activity at pH 8.0 and an optimal temperature of 40 °C for mevalonate as the substrate. The expression profiles and RNA interference of TcMevK indicated its critical role in controlling juvenile hormone biosynthesis, as well as its participation in the production of other terpenoids in T. castaneum. These findings improve our understanding of the structural and biochemical features of insect Mevk and provide a structural basis for the design of MevK inhibitors.

Practical Approach to Diagnosis and Management of IL-1-Mediated Autoinflammatory Diseases (CAPS, TRAPS, MKD, and DIRA).

Systemic autoinflammatory diseases (SAIDs) are a group of rare genetic and nongenetic immune dysregulatory disorders associated with high morbidity and mortality if left untreated. Therefore, early diagnosis and initiation of targeted treatment is vital in SAID patients to control the disease activity and prevent long-term immune-mediated damage. A specific group of genetically defined SAIDs is associated with increased inflammasome-mediated production of active interleukin (IL)-1. Even though progress in immunobiology and genetics has brought forth diagnostic tools and novel treatments that have been described in the literature extensively, many challenges remain in the clinical setting. Some challenges that health care providers may face on a day-to-day basis include the requirement of a multidisciplinary approach due to the complexity of these diseases, limited evidence-based treatment options, and barriers to access available therapies. Primarily, IL-1 inhibitors anakinra, canakinumab, and rilonacept are used to control the inflammation in these patients, with the goal of achieving sustainable remission. Recently published provisional points to consider from the European Alliance of Associations for Rheumatology (EULAR) and American College of Rheumatology (ACR) provide diagnosis, management, and monitoring recommendations for four IL-1-mediated autoinflammatory diseases: cryopyrin-associated periodic syndromes (CAPS), tumour necrosis factor receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD), and deficiency of the IL-1 receptor antagonist (DIRA). The goal of this paper is to aid health care professionals by providing a practical approach to diagnosis and management of these four IL-1 mediated SAIDs on the basis of the recent EULAR/ACR recommendations.

Complex MEFV and MVK Variations in a Syrian Child: Implications for Clinical Phenotypes and Treatment Response-A Case Report.

This case report presents a 10-year-old Syrian boy with concurrent mutations in the Mediterranean fever (MEFV) and mevalonate kinase (MVK) genes, resulting in overlapping symptoms of Familial Mediterranean Fever (FMF) and Hyperimmunoglobulinemia D syndrome (HIDS), both classified as Periodic Fever Syndromes (PFSs). The co-occurrence of these mutations within a single individual is highly unusual. He presented with pallor, intermittent fever, and recurrent respiratory infections from an early age, along with anemia, splenomegaly, hepatomegaly, cervical lymphadenopathy, and growth failure noted in initial investigations. Still's disease was initially considered as the most likely differential diagnosis, leading to the initiation of treatment with methylprednisolone; however, the parents did not follow-up with the treatment. The child returned at 5 years old with appendicitis, which was surgically removed, and parents reported recurrent episodes of arthralgia and joint swelling accompanied by nearly daily fever. Although the child experienced delayed motor development, his cognitive abilities were normal. Genetic analysis identified a homozygous likely pathogenic variant in the MVK gene and a heterozygous likely pathogenic variant in the MEFV gene. The child remains reliant on corticosteroids, with limited response to colchicine and improvement noted after transitioning from tocilizumab to infliximab. The latest follow-up demonstrated significant improvement with no fever, joint swelling, or lymphadenopathy; however, signs of growth failure persist. The atypical manifestations observed in this case may indicate a synergistic effect between the 2 mutations, contributing to the overall clinical picture. Therefore, although HIDS may dominate the clinical presentation, we cannot entirely dismiss the possibility that the FMF mutation plays a role in modulating these symptoms.

A Clinico-Epidemiological Study on Porokeratosis.

Porokeratosis (PK) is a chronic progressive disorder of keratinization characterized clinically by hyperkeratotic papules or plaques surrounded by a threadlike, elevated border that expands centrifugally. Pathogenesis involves heterozygous mutations in mevalonate kinase enzyme. The most common variants are disseminated superficial actinic porokeratosis (DSAP) and PK of Mibelli. All forms show a thin column of parakeratosis, the cornoid lamella, representing the active border. Dermoscopy reveals central brownish discoloration surrounded by a single hypopigmented band and a peripheral 'white track'. Long-standing cases of PK may undergo malignant transformation. UV-protection and topical agents, such as 5-fluorouracil, imiquimod, calcipotriol, tretinoin and oral retinoids are helpful. To study the clinical and epidemiological pattern of PK and the clinico-dermoscopic and histopathological correlation of PK. A prospective cross-sectional study was conducted on the patients attending the dermatology outpatient department (OPD) over 9 months with suspected features of PK. These patients were evaluated clinically and subjected to dermoscopy and histopathology. Statistical Package for the Social Sciences (SPSS) Of 11 patients, there were four (36.36%) males and seven (63.66%) females. The youngest was 18-year-old boy, and the eldest was 63-year-old man. The clinically most common type was PK of Mibelli with five (45.45%) cases. The most common dermoscopic feature observed was double-marginated, white peripheral border. The most common histopathological feature noted was cornoid lamella. PK is a rare skin disorder with a wide spectrum of clinical variants. Dermoscopy and histopathology aid in diagnosis, whereas dermoscopy plays a pivotal role in early and non-invasive diagnosis. Regular follow-up is mandatory to watch for the development of malignancies in a few variants.

Anakinra in idiopathic recurrent pericarditis: acomprehensive case series and literature review.

Idiopathic recurrent pericarditis (IRP) is defined by recurring episodes of pericardial inflammation without aknown cause. This study investigates the safety and efficacy of anakinra, an interleukin‑1 inhibitor, as asuccessful therapy for IRP in cases resistant to conventional treatment. Aretrospective evaluation of patients treated at our autoinflammatory center between 2011 and 2023 was conducted. Patient files were examined for demographic, clinical, and treatment response data, including nonsteroid anti-inflammatory drugs (NSAIDs), corticosteroids, and colchicine. Monogenic autoinflammatory disease screening was performed for Mediterranean Fever (MEFV), tumor necrosis factor receptor-associated periodic syndrome (TRAPS), mevalonate kinase (MVK), nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3), and nucleotide-binding oligomerization domain-containing protein 2 (NOD2). Patients who experienced multiple episodes of pericarditis were diagnosed with recurrent pericarditis. The study evaluated anakinra treatment in IRP patients unresponsive to conventional therapy. The study included 21participants, 9(42.9%) female and 12(57.1%) male. The average age of the participants was 43.1 ± 16.5years. The MEFV mutation analysis revealed that 2(9.5%) had amutation in exon10 and4 (19.0%) had one in exon2. Out of the 16cases, 15successfully discontinued steroid treatment. Four patients (19.0%) experienced injection site reactions. C‑reactive protein (CRP) levels were measured at an average of 196 ± 67.8 mg/l before and 2.6 ± 3.15 mg/l after anakinra treatment. In conclusion, the study adds to the growing evidence for the efficacy of interleukin-1inhibitors, such as anakinra, as apromising treatment modality for IRP in cases resistant to conventional treatment.

Tocilizumab for treating mevalonate kinase deficiency and TNF receptor-associated periodic syndrome: a case series and literature review

BackgroundMevalonate kinase deficiency (MKD) and TNF receptor-associated periodic syndrome (TRAPS) are categorized as systemic autoinflammatory diseases (SAIDs), which are rare diseases characterized by early onset, severe conditions, and challenging diagnosis and treatment. Although different SAIDs have varying standard treatments, some SAIDs are poorly controlled after routine treatment, seriously affecting the growth and development of children and their quality of life. This study aims to provide more treatment strategies for SAIDs.Case presentationWe present two Chinese patients with MKD and TRAPS who were resistant to TNF- (tumor necrosis factor-) α blockade. After using etanercept, baricitinib, and glucocorticoid, patients with MKD and TRAPS still had periodic fever and rash. Due to the unavailability of IL-1 antagonists in the Chinese Mainland, we started administering intravenous tocilizumab (TCZ) at a dosage of 240 mg every three weeks. They had not experienced fever or rash after receiving one or two doses of TCZ. Before treatment with TCZ in the MKD patient, white blood cell (WBC) count, and TNF-α level were normal, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) increased significantly, and IL-6 increased slightly. After treatment with TCZ, ESR and CRP levels returned to normal; however, IL-6 increased occasionally. In the TRAPS patient, ESR, CRP, WBC, IL-6, and TNF-α levels were increased significantly. After TCZ treatment, ESR, CRP, WBC, IL-6, and TNF-α levels returned to normal. The two patients were treated with TCZ for more than six months and achieved clinical and serological remission. Furthermore, they had no adverse reactions after injection of TCZ.ConclusionIn the absence of IL-1 antagonists in mainland China, tocilizumab emerges as an alternative drug in SAIDs that are resistant to TNF-α blockade.

Identification of FDA-approved drugs that increase mevalonate kinase in hyper IgD syndrome.

Mevalonate kinase deficiency (MKD) is an autoinflammatory metabolic disorder caused by bi-allelic loss-of-function variants in the MVK gene, resulting in decreased activity of the encoded mevalonate kinase (MK). Clinical presentation ranges from the severe early-lethal mevalonic aciduria to the milder hyper-IgD syndrome (MKD-HIDS), and is in the majority of patients associated with recurrent inflammatory episodes with often unclear cause. Previous studies with MKD-HIDS patient cells indicated that increased temperature, as caused by fever during an inflammatory episode, lowers the residual MK activity, which causes a temporary shortage of non-sterol isoprenoids that promotes the further development of inflammation. Because an increase of the residual MK activity is expected to make MKD-HIDS patients less sensitive to developing inflammatory episodes, we established a cell-based screen that can be used to identify compounds and/or therapeutic targets that promote this increase. Using a reporter HeLa cell line that stably expresses the most common MKD-HIDS variant, MK-V377I, C-terminally tagged with bioluminescent NanoLuc luciferase (nLuc), we screened the Prestwick Chemical Library®, which includes 1280 FDA-approved compounds. Multiple compounds increased MK-V377I-nLuc bioluminescence, including steroids (i.e., glucocorticoids, estrogens, and progestogens), statins and antineoplastic drugs. The glucocorticoids increased MK-V377I-nLuc bioluminescence through glucocorticoid receptor signaling. Subsequent studies in MKD-HIDS patient cells showed that the potent glucocorticoid clobetasol propionate increases gene transcription of MVK and other genes regulated by the transcription factor sterol regulatory element-binding protein 2 (SREBP-2). Our results suggest that increasing the flux through the isoprenoid biosynthesis pathway by targeting the glucocorticoid receptor or SREBP-2 could be a potential therapeutic strategy in MKD-HIDS.

Leishmania donovani mevalonate kinase regulates host actin for inducing phagocytosis

Despite the well-established role of macrophages in phagocytosing Leishmania, the contribution of the parasite to this process is not well understood. Present study provides insights into the mechanism underlying the MVK-induced entry of L. donovani and improve our knowledge of host-pathogen interactions. We have discussed Mevalonate kinase (MVK)-induced actin reorganization, modulation of signaling pathways and host cell functions. Our results show that LdMVK gains access to macrophage cytosol and induces actin assembly modulation through the activation of actin-related proteins: VASP, Src and ERM. We have also demonstrated that LdMVK induces Ca2+ signaling and Akt pathway in macrophages, which are critical components of Leishmania survival and proliferation. Interestingly, we found that antibodies against LdMVK can kill Leishmania-infected macrophages in culture by forming extracellular traps, highlighting the potential of LdMVK in inhibiting parasite death. Overall, LdMVK is a virulent factor in Leishmania that mediates parasite internalization and host modulation by targeting host proteins phosphorylation and calcium homeostasis having significant implications in disease progression.