Pharmacogenetics of induction therapy-related toxicities in childhood acute lymphoblastic leukemia patients treated with UKALL 2003 protocol

Chemotherapy related toxicities have been the major factor limiting the success of acute lymphoblastic leukemia (ALL) induction therapy. Several factors, including the pharmacogenetics of asparaginase and anthracyclines, could contribute to difference in treatment outcome in ALL. We investigated the significance of variations in genes involved in hepatic and cardiac toxicity in acute lymphoblastic leukemia (ALL). Genotyping of SOD2 (rs4880), PNPL3 (rs738409) and ABCC1 (rs4148350), CBR1 (rs9024) and ABCG2 (rs2231142) was performed by Tetra-ARMS PCR-based technique to evaluate the genotype–phenotype correlation. Our results showed only minor allele G of SOD2 rs4880 increase the risk of hepatic toxicity [OR 2.63 (1.42–4.84), P = < 0.05] while minor alleles of other SNPs showed protective impact. However, the genetic contrast analysis showed a recessive form of SOD2 rs4880 [OR 7.82 (3.86–15.85), P = < 0.05] and PNPLA3 I148M [OR 5.82 (3.43–9.87), P = < 0.05] variants whereas dominant genotype of ABCC1 rs4148350 [OR 2.52 (1.55–4.10), P = < 0.05] significantly predisposes hepatotoxicity. Furthermore, heterozygous form of ABCG2 rs2231142 [OR 5.25 (1.84–14.95), P = < 0.05] and recessive genotype of 3′UTR variant CBR1 rs9024 [OR 2.31 (1.31–4.07), P = < 0.05] were strongly associated with cardiotoxicity. The information obtained from these genetic variations could offer biomarkers for individualization of therapeutic intervention in ALL.

CNGB3 Missense Variant Causes Recessive Achromatopsia in Original Braunvieh Cattle

Sporadic occurrence of inherited eye disorders has been reported in cattle but so far pathogenic variants were found only for rare forms of cataract but not for retinopathies. The aim of this study was to characterize the phenotype and the genetic aetiology of a recessive form of congenital day-blindness observed in several cases of purebred Original Braunvieh cattle. Electroretinography in an affected calf revealed absent cone-mediated function, whereas the rods continue to function normally. Brain areas involved in vision were morphologically normal. When targeting cones by immunofluorescence, a decrease in cone number and an accumulation of beta subunits of cone cyclic-nucleotide gated channel (CNGB3) in the outer plexiform layer of affected animals was obvious. Achromatopsia is a monogenic Mendelian disease characterized by the loss of cone photoreceptor function resulting in day-blindness, total color-blindness, and decreased central visual acuity. After SNP genotyping and subsequent homozygosity mapping with twelve affected cattle, we performed whole-genome sequencing and variant calling of three cases. We identified a single missense variant in the bovine CNGB3 gene situated in a ~2.5 Mb homozygous genome region on chromosome 14 shared between all cases. All affected cattle were homozygous carriers of the p.Asp251Asn mutation that was predicted to be deleterious, affecting an evolutionary conserved residue. In conclusion, we have evidence for the occurrence of a breed-specific novel CNGB3-related form of recessively inherited achromatopsia in Original Braunvieh cattle which we have designated OH1 showing an allele frequency of the deleterious allele of ~8%. The identification of carriers will enable selection against this inherited disorder. The studied cattle might serve as an animal model to further elucidate the function of CNGB3 in mammals.

p.R138Q and p.R229Q Screening In NPHS2 Gene in a Moroccan Cohort with Steroid Resistant Nephrotic Syndrome

Mutations in the NPHS2 gene encoding podocin are implicated in an autosomal-recessive form of nonsyndromic steroid-resistant nephrotic syndrome in both pediatric and adult patients. The p.R138Q (c.413G>A) mutation in exon 3 was the most prevalent mutation in European series. The p.R229Q (c.686G>A) variant in exon 5 is the first human variant discovered with a mutation-dependent pathogenicity. We aimed in this study to screen for the p.R138Q mutation and the p.R138Q variant in a Moroccan cohort with Steroid Resistant Nephrotic Syndrome.

Impact of SOD2, PNPLA3, ABCC1, CBR1 And ABCG2 Variants Upon Toxicities of Induction Therapy In Childhood Acute Lymphoblastic Leukemia

Chemotherapy related toxicities have been the major factor limiting the success of acute lymphoblastic leukemia (ALL) induction therapy. Several factors, including the pharmacogenetics of asparagenase and anthracyclines, could contribute to difference in treatment outcome in ALL. We investigated the significance of variations in genes that are involved in hepatic toxicity and cardiotoxicity in acute lymphoblastic leukemia (ALL). Genotyping of SOD2 (rs4880), PNPL3 (rs738409) and ABCC1 (rs4148350), CBR1 (rs9024) and ABCG2 (rs2231142) was performed by Tetra-ARMS PCR-based technique to evaluate the genotype-phenotype correlation. Our results showed only the minor allele G of SOD2 rs4880 increase the risk of hepatic toxicity [OR=2.63 (1.42-4.84), P=<.05] while minor alleles of other SNPs showed protective impact. However, the genetic contrast analysis showed a recessive form of SOD2 rs4880 [OR=7.82 (3.86-15.85), P=<0.05] and PNPLA3 I148M [OR=5.82 (3.43-9.87), P=<0.05] variants whereas dominant genotype of ABCC1 rs4148350 [OR=2.52 (1.55-4.10), P=<0.05] significantly predisposes hepatotoxicity. Furthermore, heterozygous form of ABCG2 rs2231142 [OR=5.25 (1.84-14.95), P=<0.05] and recessive genotype of 3′UTR variant CBR1 rs9024 [OR=2.31 (1.31-4.07), P=<0.05] were strongly associated with cardiotoxicity. The information obtained from these genetic variations could offer biomarkers for individualization of therapeutic intervention in ALL.

Cytoprotective Mechanisms of DJ-1: Implications in Cardiac Pathophysiology

DJ-1 was originally identified as an oncogene product while mutations of the gene encoding DJ-1/PARK7 were later associated with a recessive form of Parkinson’s disease. Its ubiquitous expression and diversity of function suggest that DJ-1 is also involved in mechanisms outside the central nervous system. In the last decade, the contribution of DJ-1 to the protection from ischemia-reperfusion injury has been recognized and its involvement in the pathophysiology of cardiovascular disease is attracting increasing attention. This review describes the current and gaps in our knowledge of DJ-1, focusing on its role in regulating cardiovascular function. In parallel, we present original data showing an association between increased DJ-1 expression and antiapoptotic and anti-inflammatory markers following cardiac and vascular surgical procedures. Future studies should address DJ-1′s role as a plausible novel therapeutic target for cardiovascular disease.

A Bi-allelic Frameshift Mutation in NPNT Causes Bilateral Renal Agenesis in Humans

Background: Bilateral renal agenesis (BRA) is a lethal congenital anomaly caused by the failure of normal development of both kidneys early in embryonic development. Oligohydramnios upon fetal ultrasonography reveals BRA. Although exact causes are not clear, BRA is associated with mutations in many renal development genes. However, molecular diagnostics cannot pick up many clinical cases. Nephronectin (NPNT) may be a candidate protein for widening diagnosis. It is essential in kidney development and knockout of Npnt in mice frequently leads to kidney agenesis or hypoplasia. Methods: A consanguineous Han family experienced three cases of induced abortion in the second trimester of pregnancy due to suspicion of BRA. Whole-exome sequencing-(WES)-:based homozygosity mapping detected underlying genetic factors, and a knock-in mouse model confirmed the renal agenesis phenotype. Results: WES and evaluation of homozygous regions in II-3 and II-4 revealed a pathological homozygous frameshift variant in NPNT (NM_001184690:exon8:c.777dup/p.Lys260*), which leads to a premature stop in the next codon. The truncated NPNT protein exhibited decreased expression, as confirmed in vivo by the overexpression of WT and mutated NPNT. A knock-in mouse model homozygous for the detected Npnt mutation replicated the BRA phenotype. Conclusions: A biallelic loss-of-function NPNT mutation causing an autosomal recessive form of BRA in humans was confirmed by the corresponding phenotype of knock-in mice. Our results identify a novel genetic cause of BRA, revealing a new target for genetic diagnosis, prenatal diagnosis, and preimplantation diagnosis for families with BRA.

Progression of a Muscular Dystrophy Due to a Genetic Defect in Membrane Synthesis is Driven by Large Changes in Neutral Lipid Metabolism

CHKB encodes one of two mammalian choline kinase enzymes that catalyze the first step in the synthesis of the major membrane phospholipid, phosphatidylcholine (PC). In humans, inactivation of the CHKB gene causes a recessive form of a rostral-to-caudal congenital muscular dystrophy. Using Chkb knockout mice, we reveal that at no stage of the disease is PC level significantly altered. Instead, at early stages of the disease the level of mitochondrial specific lipids acylcarnitine (AcCa) and cardiolipin (CL) increase 15-fold and 10-fold, respectively. Importantly, these changes are only observed in affected muscle and contribute to the decrease in the skeletal muscle functional output in these mice. As the disease progresses, AcCa and CL levels normalize and there is a 12-fold increase in the neutral storage lipid triacylgycerol and a 3-fold increase in its upstream lipid diacylglycerol. Our findings indicate that the major changes in lipid metabolism upon loss of function of Chkb is not a change in PC level, but instead is an initial inability to utilize fatty acids for energy resulting in shunting of fatty acids into triacyglycerol.

hTERT-Driven Immortalization of RDEB Fibroblast and Keratinocyte Cell Lines Followed by Cre-Mediated Transgene Elimination

The recessive form of dystrophic epidermolysis bullosa (RDEB) is a crippling disease caused by impairments in the junctions of the dermis and the basement membrane of the epidermis. Using ectopic expression of hTERT/hTERT + BMI-1 in primary cells, we developed expansible cultures of RDEB fibroblasts and keratinocytes. We showed that they display the properties of their founders, including morphology, contraction ability and expression of the respective specific markers including reduced secretion of type VII collagen (C7). The immortalized keratinocytes retained normal stratification in 3D skin equivalents. The comparison of secreted protein patterns from immortalized RDEB and healthy keratinocytes revealed the differences in the contents of the extracellular matrix that were earlier observed specifically for RDEB. We demonstrated the possibility to reverse the genotype of immortalized cells to the state closer to the progenitors by the Cre-dependent hTERT switch off. Increased β-galactosidase activity and reduced proliferation of fibroblasts were shown after splitting out of transgenes. We anticipate our cell lines to be tractable models for studying RDEB from the level of single-cell changes to the evaluation of 3D skin equivalents. Our approach permits the creation of standardized and expandable models of RDEB that can be compared with the models based on primary cell cultures.