pepD Gene Research Articles

Characterizing and optimizing glutamate decarboxylase from Priestia flexa for efficient biosynthesis of γ-aminobutyric acid from l-glutamic acid powder

Gamma-aminobutyric acid (GABA) is widely applied in the food and pharmaceutical industries, and is experiencing a continually growing market demand. Nevertheless, the efficient and stable production of GABA confronts challenges, especially the instability of its core enzyme, glutamate decarboxylase (GAD). GAD exhibits high activity under acidic conditions but very poor stability. This limitation severely restricts its application in large-scale industrial production. In this study, we identified and characterized a GAD from Priestia flexa (PfGAD) with high activity. We further developed a variant with significantly enhanced acidic st ability. The specific activity of the variant achieved 139.8 U/mg, and its residual activity remained approximately 90 % after overnight incubation in pH 3.0 buffer. Moreover, we engineered a strain by overexpressing a transporter protein for GABA and l-glutamic acid, while deleting the pepD gene. The yield of GABA led to 251.8 g L−1, accompanied by a conversation rate of 97.8 %, meanwhile the cell growth maintained normal. Our approach successfully addresses the challenge of balancing cell growth and GABA accumulation. Our findings offer valuable insights into acid resistance modification of the enzyme, and optimizing GABA production through strain modification, holding significant potential for the industrial application of GABA.

A rare cause of immune dysregulation, prolidase deficiency: a case report and review of the literature.

We report a pediatric patient with prolidase deficiency, caused by a mutation in the PEPD gene, which encodes the enzyme prolidase D, with a lupus-like clinic and marked dysmorphic features along with pulmonary, neurological, skeletal, and immune system involvement. In addition to being the first known case in the literature where Friedrich's ataxia and prolidase deficiency were observed together, we aimed to highlight that this diagnosis should be considered in patients with autoimmunity and additional systemic findings such as treatment-resistant skin lesions, intellectual disability, and pulmonary manifestations. Furthermore, we sought to compare this case with others documented in the literature.

Establishment of a human induced pluripotent stem cell line, KMUGMCi007-A, from a patient with prolidase deficiency (PD) bearing homozygous in-frame mutation in the PEPD gene

Prolidase deficiency (PD) is a rare autosomal recessive disorder characterized mainly by skin lesions of the legs and feet, respiratory infections and mental retardation, and impaired immune system. To date, no effective PD treatment has been developed. The PD case are caused by homozygous mutation in PEPD gene. The peripheral blood mononuclear cells from a patient carrying homozygous in-frame mutation of the PEPD gene were reprogrammed using the CytoTune-iPS2.0 Sendai Reprogramming Kit. The homozygous in-frame mutation in PEPD will cause the abnormal protein variant. The established human induced pluripotent cell line will enable proper in vitro disease modelling of PD.

Prolidase Deficiency Causes Spontaneous T Cell Activation and Lupus-like Autoimmunity.

Prolidase deficiency (PD) is a multisystem disorder caused by mutations in the PEPD gene, which encodes a ubiquitously expressed metallopeptidase essential for the hydrolysis of dipeptides containing C-terminal proline or hydroxyproline. PD typically presents in childhood with developmental delay, skin ulcers, recurrent infections, and, in some patients, autoimmune features that can mimic systemic lupus erythematosus. The basis for the autoimmune association is uncertain, but might be due to self-antigen exposure with tissue damage, or indirectly driven by chronic infection and microbial burden. In this study, we address the question of causation and show that Pepd-null mice have increased antinuclear autoantibodies and raised serum IgA, accompanied by kidney immune complex deposition, consistent with a systemic lupus erythematosus-like disease. These features are associated with an accumulation of CD4 and CD8 effector T cells in the spleen and liver. Pepd deficiency leads to spontaneous T cell activation and proliferation into the effector subset, which is cell intrinsic and independent of Ag receptor specificity or antigenic stimulation. However, an increase in KLRG1+ effector CD8 cells is not observed in mixed chimeras, in which the autoimmune phenotype is also absent. Our findings link autoimmune susceptibility in PD to spontaneous T cell dysfunction, likely to be acting in combination with immune activators that lie outside the hemopoietic system but result from the abnormal metabolism or loss of nonenzymatic prolidase function. This knowledge provides insight into the role of prolidase in the maintenance of self-tolerance and highlights the importance of treatment to control T cell activation.

Next-generation sequencing of prolidase gene identifies novel and common variants associated with low prolidase in coronary artery ectasia.

Decreased collagen biosynthesis and increased collagenolysis can cause ectasia progression in the arterial walls. Prolidase is a key enzyme in collagen synthesis; a decrease in prolidase activity or level may decrease collagen biosynthesis, which may contribute to ectasia formation. Considering that, the variations in PEPD gene encoding prolidase enzyme were evaluated by analyzing next-generation sequencing (NGS) for the first time together with known risk factors in coronary artery ectasia (CAE) patients. Molecular analysis of the PEPD gene was performed on genomic DNA by NGS in 76 CAE patients and 76 controls. The serum levels of prolidase were measured by the sandwich-ELISA technique. Serum prolidase levels were significantly lower in CAE group compared to control group, and it was significantly lower in males than females in both groups (p < 0.001). On the other hand, elevated prolidase levels were observed in CAE patients in the presence of diabetes (p < 0.001), hypertension (p < 0.05) and hyperlipidemia (p < 0.05). Logistic regression analysis demonstrated that the low prolidase level (p < 0.001), hypertension (p < 0.02) and hyperlipidemia (p < 0.012) were significantly associated with increased CAE risk. We identified four missense mutations in the PEPD gene, namely G296S, T266A, P365L and S134C (novel) that could be associated with CAE. The pathogenicity of these mutations was predicted to be "damaging" for G296S, S134C and P365L, but "benign" for T266A. We also identified a novel 5'UTR variation (Chr19:34012748 G>A) in one patient who had a low prolidase level. In addition, rs17570 and rs1061338 common variations of the PEPD gene were associated with low prolidase levels in CAE patients, while rs17569 variation was associated with high prolidase levels in both CAE and controls (p < 0.05). Our findings indicate that the low serum prolidase levels observed in CAE patients is significantly associated with PEPD gene variations. It was concluded that low serum prolidase level and associated PEPD mutations may be potential biomarkers for the diagnosis of CAE.

MEFV, IRF8, ADA, PEPD, and NBAS gene variants and elevated serum cytokines in a patient with unilateral sporadic Meniere's disease and vascular congestion over the endolymphatic sac

The etiology and underlying mechanism of Meniere's disease (MD) development are still unknown, although inflammation and autoimmunity have been implicated as underlying mechanisms. The human endolymphatic sac (ES) has been reported to have innate and adaptive immune capacity in local immune reactions. In vivo demonstration of inflammation of the ES in patients with MD is missing in the literature. We report the case of a 47-year-old female patient diagnosed with unilateral MD with genetic variants and cytokine markers indicating inflammation and vascular congestion of the ES. Endolymphatic hydrops in the right cochlea (grade 2) and vestibulum (grade 3) were detected using MRI. She carried heterozygous variants in MEFV (c.442G > C), IRF8 (c.1157G > T), ADA (c.445C > T), PEPD (c.151G > A), NBAS (c.4049T > C), CSF2RB (c.2222C > T), HPS6 (c.277G > T), IL2RB (c.1109C > T), IL12RB1 (c.1384G > T), IL17RC (c.260_271del GCAAGAGC TGGG), LIG1 (c.746G > A), RAG1 (c.650C > A), and SLX4 (c.1258G > C, c.5072A > G). In the serum, the levels of granulocyte colony-stimulating factor (G-CSF), macrophage inflammatory protein 1α, and IL7 were significantly elevated, and the level of IL2Rα was reduced. Intratympanic administration of dexamethasone temporarily alleviated her hearing loss. Her vertigo was significantly relieved but remained slight after ES administration of corticosteroids.

Prolidase deficiency, a rare inborn error of immunity, clinical phenotypes, immunological features, and proposed treatments in twins

BackgroundProlidase deficiency (PD) is an autosomal recessive inborn multisystemic disease caused by mutations in the PEPD gene encoding the enzyme prolidase D, leading to defects in turnover of proline-containing proteins, such as collagen. PD is categorized as a metabolic disease, but also as an inborn error of immunity. PD presents with a range of findings including dysmorphic features, intellectual disabilities, recurrent infections, intractable skin ulceration, autoimmunity, and splenomegaly. Despite symptoms of immune dysregulation, only very limited immunologic assessments have been reported and standard therapies for PD have not been described. We report twin females with PD, including comprehensive immunologic profiles and treatment modalities used.Case presentationPatient 1 had recurrent infections in childhood. At age 13, she presented with telangiectasia, followed by painful, refractory skin ulcerations on her lower limbs, where skin biopsy excluded vasculitis. She had typical dysmorphic features of PD. Next-generation sequencing revealed pathogenic compound heterozygous mutations (premature stop codons) in the PEPD gene. Patient 2 had the same mutations, typical PD facial features, atopy, and telangiectasias, but no skin ulceration. Both patients had imidodipeptiduria. Lymphocyte subset analysis revealed low-normal frequency of Treg cells and decreased frequency of expression of the checkpoint molecule CTLA-4 in CD4+ TEM cells. Analysis of Th1, Th2, and Th17 profiles revealed increased inflammatory IL-17+ CD8+ TEM cells in both patients and overexpression of the activation marker HLA-DR on CD4+ TEM cells, reflecting a highly activated proinflammatory state. Neither PD patient had specific antibody deficiencies despite low CD4+CXCR5+ Tfh cells and low class-switched memory B cells. Plasma IL-18 levels were exceptionally high.ConclusionsImmunologic abnormalities including skewed frequencies of activated inflammatory CD4+ and CD8+ TEM cells, decreased CTLA-4 expression, and defects in memory B cells may be a feature of immune dysregulation associated with PD; however, a larger sample size is required to validate these findings. The high IL-18 plasma levels suggest underlying autoinflammatory processes.

PROLIDASE: A Review from Discovery to its Role in Health and Disease.

Prolidase (peptidase D), encoded by the PEPD gene, is a ubiquitously expressed cytosolic metalloproteinase, the only enzyme capable of cleaving imidodipeptides containing C-terminal proline or hydroxyproline. Prolidase catalyzes the rate-limiting step during collagen recycling and is essential in protein metabolism, collagen turnover, and matrix remodeling. Prolidase, therefore plays a crucial role in several physiological processes such as wound healing, inflammation, angiogenesis, cell proliferation, and carcinogenesis. Accordingly, mutations leading to loss of prolidase catalytic activity result in prolidase deficiency a rare autosomal recessive metabolic disorder characterized by defective wound healing. In addition, alterations in prolidase enzyme activity have been documented in numerous pathological conditions, making prolidase a useful biochemical marker to measure disease severity. Furthermore, recent studies underscore the importance of a non-enzymatic role of prolidase in cell regulation and infectious disease. This review aims to provide comprehensive information on prolidase, from its discovery to its role in health and disease, while addressing the current knowledge gaps.

Structural analysis of new compound heterozygous variants in PEPD gene identified in a patient with Prolidase Deficiency diagnosed by exome sequencing

Prolidase Deficiency (PD) is an autosomal recessive rare disorder caused by loss or reduction of prolidase enzymatic activity due to variants in the PEPD gene. PD clinical features vary among affected individuals: skin ulcerations, recurrent infections, and developmental delay are common. In this study, we describe a 16-year-old boy with a mild PD phenotype comprising chronic eczema, recurrent infections and elevated IgE. Whole exome sequencing analysis revealed three PEPD variants: c.575T>C p.(Leu192Pro) inherited from the mother, and c.692_694del p.(Tyr231del) and c.1409G>A p.(Arg470His), both inherited from the father. The variant p.(Tyr231del) has been previously characterized by high-resolution X-ray structure analysis as altering protein dynamics/flexibility. In order to study the effects of the other two prolidase variants, we performed site directed mutagenesis purification and crystallization studies. A high-resolution X-ray structure could only be obtained for the p.(Arg470His) variant, which showed no significant structural differences in comparison to WT prolidase. On the other hand, the p.(Leu192Pro) variant led to significant protein destabilization. Hence, we conclude that the maternal p.(Leu192Pro) variant was likely causally associated with the proband´s disease, together with the known pathogenic paternal variant p.(Tyr231del). Our results demonstrated the utility of exome sequencing to perform diagnosis in PD cases with mild phenotype.

Mapping the Minimal Promoter Sequence for Human Prolidase (Peptidase D; PEPD‐ gene)

Collagen, the most abundant protein in humans, is the primary component of the extracellular matrix. Collagen is also a critical reservoir of proline that, along with hydroxyproline, comprise one‐fourth of the amino acid composition of collagen. During collagen turnover, sequential action of matrix metalloproteinases and peptidases convert collagen into dipeptides. In the subsequent final rate‐limiting step, prolidase (PEPD) hydrolyzes dipeptides containing C‐terminal proline or hydroxyproline into the constituent amino acids, which are then recycled towards collagen synthesis. Due to its critical role in collagen turnover and protein metabolism, prolidase is a key player in several physiological and pathological processes, including wound healing, cell proliferation, inflammation, and carcinogenesis. Consequently, alterations in prolidase expression can profoundly affect normal physiological processes and cause pathological changes. The goal of this study is to narrow down such knowledge gaps, especially, in our understanding of the regulation of PEPD transcription. First, towards determining a functionally active promoter region of PEPD (PEPDp), we cloned a 1587 base pair (bp) DNA region—spanning 1537 bp upstream, and 50 bp downstream, of the transcription start site (TSS)—of PEPD gene into a firefly luciferase reporter plasmid. We confirmed that the PEPDp is functionally active by demonstrating its ability to robustly drive the luciferase expression in the HEK293T cell line. Second, we sought to determine the minimal region of PEPDp that is sufficient and necessary to drive gene expression. We subcloned two progressively shorter deletion fragments of PEPDp—537 bp and 387 bp long into the firefly luciferase reporter system and then compared their promoter activity with that of the full‐length PEPDp. Our findings thus indicate that the lack of any cancellation in the promoter activity of the PEPDp deletion fragments points out that the functionally active region of PEPDp spans ~350 bp upstream and 50 bp downstream of the transcriptional start site (TSS), thereby advancing our knowledge of the molecular mechanisms regulating prolidase expression.Support or Funding InformationThis work is partly supported by National Institutes of Health (NIH) Grants DA037779 and MD007586 (to Jui Pandhare) and DA024558, DA30896, DA033892, DA021471, AI22960 and MD007586 (to Chandravanu Dash). Ireti Eni‐aganga is supported by RISE Grant. The work is also supported by the RCMI Grant G12MD007586, the Vanderbilt CTSA Grant UL1RR024975, the Meharry Translational Research Center (MeTRC) CTSA grant (U54 RR026140 from NCRR/NIH, the U54 Grant MD007593 from NIMHD/NIH, and the Tennessee Center for AIDS Research (P30 AI110527).

Studying KLF6 and PEPD‐gene Promoter by Chromatin Immunoprecipitation Assay

Prolidase (PEPD) is a ubiquitously expressed cytosolic dipeptidase that has the unique ability to cleave proline or hydroxyproline on the C‐terminus of imidodipeptides and imidotripeptides. The reaction is vital for collagen degradation. Since collagen is the most abundant protein in the body, our objective is to get a better understanding of the enzymes involved in its turnover is crucial. In silico analysis on prolidase promoter showed that putative transcription factor of interest is KLF6. To test the hypothesis that the expression of PEPD gene may be regulated by the binding of the transcription factor KLF6 to candidate binding sites we used chromatin immunoprecipitation (ChIP) assay. HEK293T cells were transfected with FLAG‐hKLF6 plasmid and the cellular lysates were obtained to measure the KLF6 protein expression by immunoblotting. After that, purified DNA from the ChIP assays were used in end‐point PCR with primers targeting candidate KLF6‐binding sites in PEPD promoter. The primers used were expected to yield a 615 bp amplicon. PCR products were resolved on 1% agarose/TAE gel. The second round of PCR was performed in which endpoint PCR products from the first round of PCR were used as a template for nested PCR with primers designed to amplify 164 bp. Nevertheless, our results showed no detectable PEPD promoter‐specific signals in the PCR analysis of the ChIP products. However, due to the inherent caveats in the experimental design, choice of reagents, and analysis method, it would be premature to conclude at this time point that PEPD expression is not regulated by KLF6. Accordingly, the design of future experiments will effectively address the limitations of this current work and will help reveal the identity of transcription factors regulating PEPD expression.Support or Funding InformationSupported by National Institutes of Health (NIH) Grants DA037779 and MD007586 (to Jui Pandhare) and DA024558, DA30896, DA033892, DA021471, AI22960 and MD007586 (to Chandravanu Dash). Ireti Eni‐Aganga is supported by RISE Grant. The work is also supported by the RCMI Grant G12MD007586, the Vanderbilt CTSA Grant UL1RR024975, the Meharry Translational Research Center (MeTRC) CTSA grant (U54 RR026140 from NCRR/NIH, the U54 Grant MD007593 from NIMHD/NIH, and the Tennessee Center for AIDS Research (P30 AI110527).

CpG Methylation Inhibits Prolidase Promoter Driven Transcription

Prolidase, a cytosolic exopeptidase, and a member of the matrix metalloproteinase (MMP) family, is encoded by the PEPD gene in humans. Since Prolidase is the only enzyme which can cleave dipeptides containing C‐terminal proline, or hydroxyproline, it plays an essential role in protein metabolism, collagen turnover, and matrix remodeling. Prolidase is essential in several physiological and pathological processes such as wound healing, inflammation, angiogenesis, cell proliferation, and carcinogenesis. Surprisingly, little is known about the molecular and cellular regulation of PEPD gene expression. In initial studies, we observed a dense CG‐rich portion around the transcription start site, suggesting a possible role of promoter methylation in the transcriptional regulation of PEPD gene. To study the transcriptional regulation of PEPD gene, we cloned and characterized the human PEPD promoter. The PEPD promoter was amplified from the human genome via PCR and inserted into a luciferase reporter construct. As demonstrated in our results, increase in luciferase activity was obtained after transfection of the PEPD luciferase reporter in HEK293T, indicating the successful construction of the luciferase reporter. Next, we performed in vitro methylation of the PEPD promoter using SssI methyltransferase which methylates DNA CpG islands. Methylation was confirmed by BstUI digestion that cleaves at unmethylated CpG dinucleotides but not at methylated CpG. The CpG methylation significantly inhibited PEPD promoter activity in comparison to the unmethylated construct. Taken together, we believe, these results will generate new knowledge on the molecular regulation of prolidase and provide better insight in our understanding of regulation of prolidase expression in various physiological and pathological conditions.Support or Funding InformationSupported by National Institutes of Health (NIH) Grants DA037779 and MD007586 (to Jui Pandhare) and DA024558, DA30896, DA033892, DA021471, AI22960 and MD007586 (to Chandravanu Dash). Ireti Eni‐Aganga is supported by RISE Grant. The work is also supported by the RCMI Grant G12MD007586, the Vanderbilt CTSA Grant UL1RR024975, the Meharry Translational Research Center (MeTRC) CTSA grant (U54 RR026140 from NCRR/NIH, the U54 Grant MD007593 from NIMHD/NIH, and the Tennessee Center for AIDS Research (P30 AI110527).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Structural basis for prolidase deficiency disease mechanisms.

All refined structure coordinates as well as the corresponding structure factor amplitudes have been deposited in the PDB under the accession numbers 5MBY, 5MBZ, 5MC0, 5MC1, 5MC2, 5MC3, 5MC4, 5MC5, 6H2P, 6H2Q.

A novel splice acceptor site mutation (IVS11 G > A) of PEPD gene causing prolidase deficiency associated with hyperimmunoglobulinemia E

Prolidase deficiency is a rare, autosomal-recessive, inborn error of collagen metabolism. We report a 20-year old girl with prolidase deficiency, who presented with spontaneous, refractory, lower extremity ulceration, elevated immunoglobulin E levels (IgE) and normal intellect. Hyperimmunoglobulin E syndrome was considered as a possible diagnosis but Th1 and Th17 T cell subsets were normal. Thin layer chromatography for examination of amino acids in random urine sample revealed proline containing peptides. Prolidase enzyme activity was undetectable in dried blood spots as well as in plasma using glycylproline as substrate. Sequence analysis of PEPD gene revealed a single nucleotide substitution (G>A) at the splice acceptor consensus sequence of AG resulting in AA at 3′ of intron 11 in both the alleles leading to skipping of entire exon 12, frame shift and premature stop codon at 278.Comparative expression profile of selected inflammatory genes was carried out in the index patient with prolidase deficiency and high immunoglobulin E levels, another patient with hyperimmunoglobulin E syndrome and a normal control. Increased expression of IL-23 and TNF-α in prolidase deficient patient while IL-6 and TNF-a in hyperimmunoglobulinemia E patient was noted. This indicates a pro-inflammatory state in hyperimmunoglobulin E syndrome compared to the stable regulatory immunological state in prolidase deficiency. To the best of our knowledge, 819-1G>A is a novel mutation of PEPD gene in patients with prolidase deficiency and elevated immunoglobulin E levels.

Brain morphological defects in prolidase deficient mice: first report.

Prolidase gene (PEPD) encodes prolidase enzyme, which is responsible for hydrolysis of dipeptides containing proline or hydroxypro-line at their C-terminal end. Mutations in PEPD gene cause, in human, prolidase deficiency (PD), a rare autosomal recessive disorder. PD patients show reduced or absent prolidase activity and a broad spectrum of phenotypic traits including various degrees of mental retardation. This is the first report correlating PD and brain damages using as a model system prolidase deficient mice, the so called dark-like (dal) mutant mice. We focused our attention on dal postnatal brain development, revealing a panel of different morphological defects in the cerebral and cerebellar cortices, such as undulations of the cerebral cortex, cell rarefaction, defects in cerebellar cortex lobulation, and blood vessels overgrowth. These anomalies might be ascribed to altered angiogenic process and loss of pial basement membrane integrity. Further studies will be directed to find a correlation between neuroarchitecture alterations and functional consequences.

Disruption of the L‐arabitol dehydrogenase encoding gene in Aspergillus tubingensis results in increased xylanase production

Fungal xylanases are of major importance to many industrial sectors, such as food and feed, paper and pulp, and biofuels. Improving their production is therefore highly relevant. We determined the molecular basis of an improved xylanase-producing strain of Aspergillus tubingensis that was generated by UV mutagenesis in an industrial strain improvement program. Using enzyme assays, gene expression, sequencing of the ladA locus in the parent and mutant, and complementation of the mutation, we were able to show that improved xylanase production was mainly caused by a chromosomal translocation that occurred between a subtilisin-like protease pepD gene and the L-arabitol dehydrogenase encoding gene (ladA), which is part of the L-arabinose catabolic pathway. This genomic rearrangement resulted in disruption of both genes and, as a consequence, the inability of the mutant to use L-arabinose as a carbon source, while growth on D-xylose was unaffected. Complementation with constitutively expressed ladA confirmed that the xylanase overproducing phenotype was mainly caused by loss of ladA function, while a knockout of xlnR in the UV mutant demonstrated that improved xylanase production was mediated by XlnR. This study demonstrates the potential of metabolic manipulation for increased production of fungal enzymes.

Identification and analysis of a novel mutation in PEPD gene in two Kashmiri siblings with prolidase enzyme deficiency

Prolidase deficiency (PD) is a rare inborn disorder of collagen metabolism characterized by chronic recurrent cutaneous ulceration. We report a novel 3bp insertion in the 12th exon of the PEPD gene in two Kashmiri siblings with prolidase deficiency phenotype. This mutation results in addition of an extra alanine residue at the amino-acid position number 304 of prolidase peptide. The structural analysis showed that this Ala insertion is located at the helix (a.a. 300–320), which contains several important hydrogen bonds between residues essential for structural folding for the enzyme activity. In silico analysis suggests that this insertion mutation might distort or bend the helical feature to affect the hydrogen-bond network between residues of neighboring secondary structures and deform the metal-binding geometry of the enzyme. Although approximately 70 PEPD gene mutations and polymorphisms have been reported in various ethnic groups, we however report, for the first time, the identification of insertion mutation in human the PEPD gene.

Prolidase deficiency associated with systemic lupus erythematosus (SLE): single site experience and literature review

IntroductionProlidase deficiency (PD) is a rare autosomal recessive disorder which may have a wide spectrum of clinical features. These features include a characteristic facies, cognitive impairment, rashes or skin ulceration, splenomegaly, recurrent infections involving mainly the respiratory system, and iminodipeptiduria. The disorder is caused by a mutation in the PEPD gene.ObjectiveTo describe a cohort of unrelated PD patients from Northern Israel whose inborn error of metabolism was associated with systemic lupus erythematosus (SLE) and to identify in the medical literature all PD cases mimicked by and/or associated with SLE.MethodsThree patients with PD associated with SLE were clinically, biochemically and genetically investigated. These patients were from 3 unrelated consanguineous families residing in Northern Israel. A computer-assisted (PubMed) search of the medical literature from 1975 to 2011 was performed using the following key words: Prolidase deficiency, SLE, and systemic lupus erythematosus.ResultsAn association between PD and SLE was found in 10 PD patients. These 10 patients included three from our cohort of 23 PD patients, and seven out of just under 70 PD patients previously reported in the literature.ConclusionThe present findings underscore the relatively high incidence of the association between SLE and PD, suggesting that this association may not be coincidental. The phenotypic similarities between SLE and PD might suggest that the PEPD gene constitutes a modifier gene or a genetic risk factor in the causation of SLE.

Prolidase function in proline metabolism and its medical and biotechnological applications

Prolidase is a multifunctional enzyme that possesses the unique ability to degrade imidodipeptides in which a proline or hydroxyproline residue is located at the C-terminal end. Prolidases have been isolated from archaea and bacteria, where they are thought to participate in proline recycling. In mammalian species, prolidases are found in the cytoplasm and function primarily to liberate proline in the final stage of protein catabolism, particularly during the biosynthesis and degradation of collagen. Collagen comprises nearly one-third of the total protein in the body, and it is essential in maintaining tissue structure and integrity. Prolidase deficiency (PD), a rare autosomal recessive disorder in which mutations in the PEPD gene affect prolidase functionality, tends to have serious and sometimes life-threatening clinical symptoms. Recombinant prolidases have many applications and have been investigated not only as a possible treatment for PD, but also as a part of anti-cancer strategies, a component of biodecontamination cocktails and in the dairy industry. This review will serve to discuss the many in vivo functions of procaryotic and eucaryotic prolidases, as well as the most recent advances in therapeutic and biotechnological application of prolidases.

A broad spectrum of developmental delay in a large cohort of prolidase deficiency patients demonstrates marked interfamilial and intrafamilial phenotypic variability

Prolidase deficiency (PD) is a rare, pan-ethnic, autosomal recessive disease with a broad phenotypic spectrum. Seventeen causative mutations in the PEPD gene have been reported worldwide. The purpose of this study is to characterize, clinically and molecularly, 20 prolidase deficient patients of Arab Moslem and Druze origin from 10 kindreds residing in northern Israel. All PD patients manifested developmental delay and facial dysmorphism. Typical PD dermatological symptoms, splenomegaly, and recurrent respiratory infections presented in varying degrees. Two patients had systemic lupus erythematosus (SLE), and one a novel cystic fibrosis phenotype. Direct DNA sequencing revealed two novel missense mutations, A212P and L368R. In addition, a previously reported S202F mutation was detected in 17 patients from seven Druze and three Arab Moslem kindreds. Patients homozygous for the S202F mutation manifest considerable interfamilial and intrafamilial phenotypic variability. The high prevalence of this mutation among Arab Moslems and Druze residing in northern Israel, and the presence of an identical haplotype along 500,000 bp in patients and their parents, suggests a founder event tracing back to before the breakaway of the Druze from mainstream Moslem society.