Bartonella species bacteremia in association with adult psychosis.

Introduction: The potential role of pathogens, particularly vector-transmitted infectious agents, as a cause of psychosis has not been intensively investigated. We have reported a potential link between Bartonella spp. bacteremia and neuropsychiatric symptoms, including pediatric acute onset neuropsychiatric syndrome and schizophrenia. The purpose of this study was to further assess whether Bartonella spp. exposure or infection are associated with psychosis. Methods: In a blinded manner, we assessed the presence of anti-Bartonella antibodies by indirect immunofluorescence assays (IFA), and infection by amplification of bacterial DNA from blood by quantitative polymerase chain reaction (qPCR), digital PCR (dPCR), and droplet digital PCR (ddPCR) in 116 participants. Participants were categorized into one of five groups: 1) controls unaffected by psychosis (n = 29); 2) prodromal participants (n = 16); 3) children or adolescents with psychosis (n = 7); 4) adults with psychosis (n = 44); and 5) relatives of a participant with psychosis (n = 20). Results: There was no significant difference in Bartonella spp. IFA seroreactivity between adults with psychosis and adult controls unaffected by psychosis. There was a higher proportion of adults with psychosis who had Bartonella spp. DNA in the bloodstream (43.2%) compared to adult controls unaffected by psychosis (14.3%, p = 0.021). The Bartonella species was determined for 18 of the 31 bacteremic participants, including infection or co-infection with Bartonella henselae (11/18), Bartonella vinsonii subsp. berkhoffii (6/18), Bartonella quintana (2/18), Bartonella alsatica (1/18), and Bartonella rochalimae (1/18). Discussion: In conjunction with other recent research, the results of this study provide justification for a large national or international multi-center study to determine if Bartonella spp. bacteremia is more prevalent in adults with psychosis compared to adults unaffected by psychosis. Expanding the investigation to include a range of vector-borne and other microbial infections with potential CNS effects would enhance knowledge on the relationship between psychosis and infection.

Distinct Th17 effector cytokines differentially promote microglial and blood-brain barrier inflammatory responses during post-infectious encephalitis.

Group A Streptococcus (GAS) infections can cause neuropsychiatric sequelae in children due to post-infectious encephalitis. Multiple GAS infections induce migration of Th17 lymphocytes from the nose into the brain, which are critical for microglial activation, blood-brain barrier (BBB) and neural circuit impairment in a mouse disease model. How endothelial cells (ECs) and microglia respond to GAS infections, and which Th17-derived cytokines are essential for these responses are unknown. Using single-cell RNA sequencing and spatial transcriptomics, we found that ECs downregulate BBB genes and microglia upregulate interferon-response, chemokine and antigen-presentation genes after GAS infections. Several microglial-derived chemokines were elevated in patient sera. Administration of a neutralizing antibody against interleukin-17A (IL-17A), but not ablation of granulocyte-macrophage colony-stimulating factor (GM-CSF) in T cells, partially rescued BBB dysfunction and microglial expression of chemokine genes. Thus, IL-17A is critical for neuropsychiatric sequelae of GAS infections and may be targeted to treat these disorders.

Neuropsychiatric Symptoms and Tick-Borne Diseases.

In North America, Lyme disease (LD) is primarily caused by the spirochetal bacterium Borrelia burgdorferi, transmitted to humans by Ixodes species tick bites, at an estimated rate of 476,000 patients diagnosed per year. Acute LD often manifests with flu-like symptoms and an expanding rash known as erythema migrans (EM) and less often with neurologic, neuropsychiatric, arthritic, or cardiac features. Most acute cases of Lyme disease are effectively treated with antibiotics, but 10-20% of individuals may experience recurrent or persistent symptoms. This chapter focuses on the neuropsychiatric aspects of Lyme disease, as these are less widely recognized by physicians and often overlooked. Broader education about the potential complexity, severity, and diverse manifestations of tick-borne diseases is needed.

The benefit of diagnostic whole genome sequencing in schizophrenia and other psychotic disorders.

Schizophrenia has a multifactorial etiology, involving a polygenic architecture. The potential benefit of whole genome sequencing (WGS) in schizophrenia and other psychotic disorders is not well studied. We investigated the yield of clinical WGS analysis in 251 families with a proband diagnosed with schizophrenia (N = 190), schizoaffective disorder (N = 49), or other conditions involving psychosis (N = 48). Participants were recruited in Israel and USA, mainly of Jewish, Arab, and other European ancestries. Trio (parents and proband) WGS was performed for 228 families (90.8%); in the other families, WGS included parents and at least two affected siblings. In the secondary analyses, we evaluated the contribution of rare variant enrichment in particular gene sets, and calculated polygenic risk score (PRS) for schizophrenia. For the primary outcome, diagnostic rate was 6.4%; we found clinically significant, single nucleotide variants (SNVs) or small insertions or deletions (indels) in 14 probands (5.6%), and copy number variants (CNVs) in 2 (0.8%). Significant enrichment of rare loss-of-function variants was observed in a gene set of top schizophrenia candidate genes in affected individuals, compared with population controls (N = 6,840). The PRS for schizophrenia was significantly increased in the affected individuals group, compared to their unaffected relatives. Last, we were also able to provide pharmacogenomics information based on CYP2D6 genotype data for most participants, and determine their antipsychotic metabolizer status. In conclusion, our findings suggest that WGS may have a role in the setting of both research and genetic counseling for individuals with schizophrenia and other psychotic disorders and their families.

Identification of small molecules that mitigate vincristine-induced neurotoxicity while sensitizing leukemia cells to vincristine.

Vincristine (VCR) is one of the most widely prescribed medications for treating solid tumors and acute lymphoblastic leukemia (ALL) in children and adults. However, its major dose-limiting toxicity is peripheral neuropathy that can disrupt curative therapy. Peripheral neuropathy can also persist into adulthood, compromising quality of life of childhood cancer survivors. Reducing VCR-induced neurotoxicity without compromising its anticancer effects would be ideal. Here, we show that low expression of NHP2L1 is associated with increased sensitivity of primary leukemia cells to VCR, and that concomitant administration of VCR with inhibitors of NHP2L1 increases VCR cytotoxicity in leukemia cells, prolongs survival of ALL xenograft mice, but decreases VCR effects on human-induced pluripotent stem cell-derived neurons and mitigates neurotoxicity in mice. These findings offer a strategy for increasing VCR's antileukemic effects while reducing peripheral neuropathy in patients treated with this widely prescribed medication.

Borrelia miyamotoi Serology in a Clinical Population With Persistent Symptoms and Suspected Tick-Borne Illness.

Eighty-two patients seeking consultation for long-term sequalae after suspected tick-borne illness were consecutively tested for Borrelia miyamotoi antibodies using a recombinant glycerophosphodiester phosphodiesterase (GlpQ) enzyme immunoassay. Twenty-one of the 82 patients (26%) tested positive on the GlpQ IgG ELISA. Nearly all of the patients (98%) had no prior B. miyamotoi testing, indicating that clinicians rarely test for this emerging tick-borne pathogen. Compared to patients who solely tested positive for Lyme disease antibodies, patients with B. miyamotoi antibodies presented with significantly more sleepiness and pain. A prospective study is needed to ascertain the relationship between the presence of B. miyamotoi antibodies and persistent symptoms.

Identification of immunoreactive linear epitopes of Borrelia miyamotoi.

Borrelia miyamotoi is an emerging tick-borne spirochete transmitted by ixodid ticks. Current serologic assays for B. miyamotoi are impacted by genetic similarities to other Borrelia and limited understanding of optimal antigenic targets. In this study, we employed the TBD-Serochip, a peptide array platform, to identify new linear targets for serologic detection of B. miyamotoi. We examined a wide range of suspected B. miyamotoi antigens and identified 352 IgM and 91 IgG reactive peptides, with the majority mapping to variable membrane proteins. These included peptides within conserved fragments of variable membrane proteins that may have greater potential for differential diagnosis. We also identified reactive regions on FlaB, and demonstrate crossreactivity of B. burgdorferi s.l. C6 with a B. miyamotoi C6-like peptide. The panel of linear peptides identified in this study can be used to enhance serodiagnosis of B. miyamotoi.

New insights into tardive dyskinesia genetics: Implementation of whole-exome sequencing approach.

Tardive dyskinesia (TD) is an adverse movement disorder induced by chronic treatment with antipsychotics drugs. The contribution of common genetic variants to TD susceptibility has been investigated in recent years, but with limited success. The aim of the current study was to investigate the potential contribution of rare variants to TD vulnerability. In order to identify TD risk genes, we performed whole-exome sequencing (WES) and gene-based collapsing analysis focusing on rare (allele frequency < 1%) and putatively deleterious variants (qualifying variants). 82 Jewish schizophrenia patients chronically treated with antipsychotics were included and classified as having severe TD or lack of any abnormal movements based on a rigorous definition of the TD phenotype. First, we performed a case-control, exome-wide collapsing analysis comparing 39 schizophrenia patients with severe TD to 3118 unrelated population controls. Then, we checked the potential top candidate genes among 43 patients without any TD manifestations. All the genes that were found to harbor one or more qualifying variants in patients without any TD features were excluded from the final list of candidate genes. Only one gene, regulating synaptic membrane exocytosis 2 (RIMS2), showed significant enrichment of qualifying variants in TD patients compared with unrelated population controls after correcting for multiple testing (Fisher's exact test p = 5.32E-08, logistic regression p = 2.50E-08). Enrichment was caused by a single variant (rs567070433) due to a frameshift in an alternative transcript of RIMS2. None of the TD negative patients had qualifying variants in this gene. In a validation cohort of 140 schizophrenia patients assessed for TD, the variant was also not detected in any individual. Some potentially suggestive TD genes were detected in the TD cohort and warrant follow-up in future studies. No significant enrichment in previously reported TD candidate genes was identified. To the best of our knowledge, this is the first WES study of TD, demonstrating the potential role of rare loss-of-function variant enrichment in this pharmacogenetic phenotype.

Inflammatory biomarkers in psychosis and clinical high risk populations.

BACKGROUND: Immunological, nutritional, and microbial factors have been implicated in the pathophysiology of schizophrenia, but the interrelationship among measures is understudied. In particular, an increase in the levels of the pro-inflammatory cytokine interleukin-6 (IL-6) is associated with all phases of the illness, and may be associated with other inflammatory markers. Vitamin D is a modulator of the immune system, and LPS antibodies are an indirect measure of gut barrier function. In this study we investigated potential contributing inflammatory mechanisms for IL-6 elevation. METHODS: We compared the levels of vitamin D, C-reactive protein (CRP), antibodies to lipopolysaccharide (LPS), and IL-6 in children, adolescents and young adults with psychosis (n = 47), individuals at clinical high risk for psychosis (n = 17) and unaffected comparison controls (n = 33). Participants were diagnosed by a psychiatrist, using a structured interview, the MINI-Neuropsychiatric Interview. 25(OH)D was measured in serum using chemiluminescent micro particle immunoassay, and anti-LPS antibodies, CRP and IL-6 levels were measured by ELISA. RESULTS: IL-6 and C-reactive protein levels were significantly elevated in the psychosis group relative to the unaffected control subjects. In the psychosis group, levels of IL-6 correlated positively with IgA anti-LPS antibodies and negatively correlated with vitamin D. CONCLUSIONS: Our findings show a significant correlation between IL-6, anti-LPS antibodies and vitamin D deficiency in psychosis, suggesting the existence of multiple potential pathways related to IL-6 elevation in psychosis, and therefore multiple potential strategies for risk mitigation. Collectively these findings support hypotheses regarding interrelated inflammatory contributions to the pathophysiology of psychosis.

Nutritional modulation of the intestinal microbiota; future opportunities for the prevention and treatment of neuroimmune and neuroinflammatory disease.

The gut-brain axis refers to the bidirectional communication between the enteric nervous system and the central nervous system. Mounting evidence supports the premise that the intestinal microbiota plays a pivotal role in its function and has led to the more common and perhaps more accurate term gut-microbiota-brain axis. Numerous studies have identified associations between an altered microbiome and neuroimmune and neuroinflammatory diseases. In most cases, it is unknown if these associations are cause or effect; notwithstanding, maintaining or restoring homeostasis of the microbiota may represent future opportunities when treating or preventing these diseases. In recent years, several studies have identified the diet as a primary contributing factor in shaping the composition of the gut microbiota and, in turn, the mucosal and systemic immune systems. In this review, we will discuss the potential opportunities and challenges with respect to modifying and shaping the microbiota through diet and nutrition in order to treat or prevent neuroimmune and neuroinflammatory disease.

Environmental Exposures and Neuropsychiatric Disorders: What Role Does the Gut-Immune-Brain Axis Play?

PURPOSE OF REVIEW: Evidence is growing that environmental exposures-including xenobiotics as well as microbes-play a role in the pathogenesis of many neuropsychiatric disorders. Underlying mechanisms are likely to be complex, involving the developmentally sensitive interplay of genetic/epigenetic, detoxification, and immune factors. Here, we review evidence supporting a role for environmental factors and disrupted gut-immune-brain axis function in some neuropsychiatric conditions. RECENT FINDINGS: Studies suggesting the involvement of an altered microbiome in triggering CNS-directed autoimmunity and neuropsychiatric disturbances are presented as an intriguing example of the varied mechanisms by which environmentally induced gut-immune-brain axis dysfunction may contribute to adverse brain outcomes. The gut-immune-brain axis is a burgeoning frontier for investigation of neuropsychiatric illness. Future translational research to define individual responses to exogenous exposures in terms of microbiome-dependent skew of the metabolome, immunity, and brain function may serve as a lens for illumination of pathways involved in the development of CNS disease and fuel discovery of novel interventions.

Gene and MicroRNA Perturbations of Cellular Response to Pemetrexed Implicate Biological Networks and Enable Imputation of Response in Lung Adenocarcinoma.

Pemetrexed is indicated for non-small cell lung carcinoma and mesothelioma, but often has limited efficacy due to drug resistance. To probe the molecular mechanisms underlying chemotherapeutic response, we performed mRNA and microRNA (miRNA) expression profiling of pemetrexed treated and untreated lymphoblastoid cell lines (LCLs) and applied a hierarchical Bayesian method. We identified genetic variation associated with gene expression in human lung tissue for the most significant differentially expressed genes (Benjamini-Hochberg [BH] adjusted p < 0.05) using the Genotype-Tissue Expression data and found evidence for their clinical relevance using integrated molecular profiling and lung adenocarcinoma survival data from The Cancer Genome Atlas project. We identified 39 miRNAs with significant differential expression (BH adjusted p < 0.05) in LCLs. We developed a gene expression based imputation model of drug sensitivity, quantified its prediction performance, and found a significant correlation of the imputed phenotype generated from expression data with survival time in lung adenocarcinoma patients. Differentially expressed genes (MTHFD2 and SUFU) that are putative targets of differentially expressed miRNAs also showed differential perturbation in A549 fusion lung tumor cells with further replication in A549 cells. Our study suggests pemetrexed may be used in combination with agents that target miRNAs to increase its cytotoxicity.

Application of stem cell derived neuronal cells to evaluate neurotoxic chemotherapy.

The generation of induced pluripotent stem cells (iPSCs) and differentiation to cells composing major organs has opened up the possibility for a new model system to study adverse toxicities associated with chemotherapy. Therefore, we used human iPSC-derived neurons to study peripheral neuropathy, one of the most common adverse effects of chemotherapy and cause for dose reduction. To determine the utility of these neurons in investigating the effects of neurotoxic chemotherapy, we measured morphological differences in neurite outgrowth, cell viability as determined by ATP levels and apoptosis through measures of caspase 3/7 activation following treatment with clinically relevant concentrations of platinating agents (cisplatin, oxaliplatin and carboplatin), taxanes (paclitaxel, docetaxel and nab-paclitaxel), a targeted proteasome inhibitor (bortezomib), an antiangiogenic compound (thalidomide), and 5-fluorouracil, a chemotherapeutic that does not cause neuropathy. We demonstrate differential sensitivity of neurons to mechanistically distinct classes of chemotherapeutics. We also show a dose-dependent reduction of electrical activity as measured by mean firing rate of the neurons following treatment with paclitaxel. We compared neurite outgrowth and cell viability of iPSC-derived cortical (iCell® Neurons) and peripheral (Peri.4U) neurons to cisplatin, paclitaxel and vincristine. Goshajinkigan, a Japanese herbal neuroprotectant medicine, was protective against paclitaxel-induced neurotoxicity but not oxaliplatin as measured by morphological phenotypes. Thus, we have demonstrated the utility of human iPSC-derived neurons as a useful model to distinguish drug class differences and for studies of a potential neuroprotectant for the prevention of chemotherapy-induced peripheral neuropathy.

Is there sexual dimorphism of hyperserotonemia in autism spectrum disorder?

Approximately 30% of individuals with autism spectrum disorder (ASD) have elevated whole blood serotonin (5-HT) levels. Genetic linkage and association studies of ASD and of whole blood 5-HT levels as a quantitative trait have revealed sexual dimorphism. Few studies have examined the presence of a sex difference on hyperserotonemia within ASD. To assess whether the rate of hyperserotonemia is different in males than in females with ASD, we measured whole blood 5-HT levels in 292 children and adolescents with ASD, the largest sample in which this biomarker has been assessed. Based upon previous work suggesting that hyperserotonemia is more common prior to puberty, we focused our analysis on the 182 pre-pubertal children with ASD. 42% of pre-pubertal participants were within the hyperserotonemia range. In this population, we found that males were significantly more likely to manifest hyperserotonemia than females (P = 0.03). As expected, no significant difference was found in the post-pubertal population. Additional work will be needed to replicate this intriguing finding and to understand whether it could potentially explain differences in patterns of ASD risk between males and females. Autism Res 2017, 10: 1417-1423. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Evaluation of inter-batch differences in stem-cell derived neurons.

Differentiated cells retain the genetic information of the donor but the extent to which phenotypic differences between donors or batches of differentiated cells are explained by variation introduced during the differentiation process is not fully understood. In this study, we evaluated four separate batches of commercially available neurons originating from the same iPSCs to investigate whether the differentiation process used in manufacturing iPSCs to neurons affected genome-wide gene expression and modified cytosines, or neuronal sensitivity to drugs. No significant changes in gene expression, as measured by RNA-Seq, or cytosine modification levels, as measured by the Illumina 450K arrays, were observed between batches relative to changes over time. As expected, neurotoxic chemotherapeutics affected neuronal outgrowth, but no inter-batch differences were observed in sensitivity to paclitaxel, vincristine and cisplatin. As a testament to the utility of the model for studies of neuropathy, we observed that genes involved in neuropathy had relatively higher expression levels in these samples across different time points. Our results suggest that the process used to differentiate iPSCs into neurons is consistent, resulting in minimal intra-individual variability across batches. Therefore, this model is reasonable for studies of human neuropathy, druggable targets to prevent neuropathy, and other neurological diseases.

Pharmacoethnicity in Paclitaxel-Induced Sensory Peripheral Neuropathy.

PURPOSE: Paclitaxel is used worldwide in the treatment of breast, lung, ovarian, and other cancers. Sensory peripheral neuropathy is an associated adverse effect that cannot be predicted, prevented, or mitigated. To better understand the contribution of germline genetic variation to paclitaxel-induced peripheral neuropathy, we undertook an integrative approach that combines genome-wide association study (GWAS) data generated from HapMap lymphoblastoid cell lines (LCL) and Asian patients. METHODS: GWAS was performed with paclitaxel-induced cytotoxicity generated in 363 LCLs and with paclitaxel-induced neuropathy from 145 Asian patients. A gene-based approach was used to identify overlapping genes and compare with a European clinical cohort of paclitaxel-induced neuropathy. Neurons derived from human-induced pluripotent stem cells were used for functional validation of candidate genes. RESULTS: SNPs near AIPL1 were significantly associated with paclitaxel-induced cytotoxicity in Asian LCLs (P < 10(-6)). Decreased expression of AIPL1 resulted in decreased sensitivity of neurons to paclitaxel by inducing neurite morphologic changes as measured by increased relative total outgrowth, number of processes and mean process length. Using a gene-based analysis, there were 32 genes that overlapped between Asian LCL cytotoxicity and Asian patient neuropathy (P < 0.05), including BCR. Upon BCR knockdown, there was an increase in neuronal sensitivity to paclitaxel as measured by neurite morphologic characteristics. CONCLUSIONS: We identified genetic variants associated with Asian paclitaxel-induced cytotoxicity and functionally validated the AIPL1 and BCR in a neuronal cell model. Furthermore, the integrative pharmacogenomics approach of LCL/patient GWAS may help prioritize target genes associated with chemotherapeutic-induced peripheral neuropathy.

Association of an inherited genetic variant with vincristine-related peripheral neuropathy in children with acute lymphoblastic leukemia.

IMPORTANCE: With cure rates of childhood acute lymphoblastic leukemia (ALL) exceeding 85%, there is a need to mitigate treatment toxicities that can compromise quality of life, including peripheral neuropathy from vincristine treatment. OBJECTIVE: To identify genetic germline variants associated with the occurrence or severity of vincristine-induced peripheral neuropathy in children with ALL. DESIGN, SETTING, AND PARTICIPANTS: Genome-wide association study of patients in 1 of 2 prospective clinical trials for childhood ALL that included treatment with 36 to 39 doses of vincristine. Genome-wide single-nucleotide polymorphism (SNP) analysis and vincristine-induced peripheral neuropathy were assessed in 321 patients from whom DNA was available: 222 patients (median age, 6.0 years; range, 0.1-18.8 years) enrolled in 1994-1998 in the St Jude Children's Research Hospital protocol Total XIIIB with toxic effects follow-up through January 2001, and 99 patients (median age, 11.4 years; range, 3.0-23.8 years) enrolled in 2007-2010 in the Children's Oncology Group (COG) protocol AALL0433 with toxic effects follow-up through May 2011. Human leukemia cells and induced pluripotent stem cell neurons were used to assess the effects of lower CEP72 expression on vincristine sensitivity. EXPOSURE: Treatment with vincristine at a dose of 1.5 or 2.0 mg/m2. MAIN OUTCOMES AND MEASURES: Vincristine-induced peripheral neuropathy was assessed at clinic visits using National Cancer Institute criteria and prospectively graded as mild (grade 1), moderate (grade 2), serious/disabling (grade 3), or life threatening (grade 4). RESULTS: Grade 2 to 4 vincristine-induced neuropathy during continuation therapy occurred in 28.8% of patients (64/222) in the St Jude cohort and in 22.2% (22/99) in the COG cohort. A SNP in the promoter region of the CEP72 gene, which encodes a centrosomal protein involved in microtubule formation, had a significant association with vincristine neuropathy (meta-analysis P = 6.3×10(-9)). This SNP had a minor allele frequency of 37% (235/642), with 50 of 321 patients (16%; 95% CI, 11.6%-19.5%) homozygous for the risk allele (TT at rs924607). Among patients with the high-risk CEP72 genotype (TT at rs924607), 28 of 50 (56%; 95% CI, 41.2%-70.0%) developed at least 1 episode of grade 2 to 4 neuropathy, a higher rate than in patients with the CEP72 CC or CT genotypes (58/271 patients [21.4%; 95% CI, 16.9%-26.7%]; P = 2.4×10(-6)). The severity of neuropathy was greater in patients homozygous for the TT genotype compared with patients with the CC or CT genotype (2.4-fold by Poisson regression [P<.0001] and 2.7-fold based on mean grade of neuropathy: 1.23 [95% CI, 0.74-1.72] vs 0.45 [95% CI, 0.3-0.6]; P = .004 by t test). Reducing CEP72 expression in human neurons and leukemia cells increased their sensitivity to vincristine. CONCLUSIONS AND RELEVANCE: In this preliminary study of children with ALL, an inherited polymorphism in the promoter region of CEP72 was associated with increased risk and severity of vincristine-related peripheral neuropathy. If replicated in additional populations, this finding may provide a basis for safer dosing of this widely prescribed anticancer agent.

Modeling chemotherapeutic neurotoxicity with human induced pluripotent stem cell-derived neuronal cells.

There are no effective agents to prevent or treat chemotherapy-induced peripheral neuropathy (CIPN), the most common non-hematologic toxicity of chemotherapy. Therefore, we sought to evaluate the utility of human neuron-like cells derived from induced pluripotent stem cells (iPSCs) as a means to study CIPN. We used high content imaging measurements of neurite outgrowth phenotypes to compare the changes that occur to iPSC-derived neuronal cells among drugs and among individuals in response to several classes of chemotherapeutics. Upon treatment of these neuronal cells with the neurotoxic drug paclitaxel, vincristine or cisplatin, we identified significant differences in five morphological phenotypes among drugs, including total outgrowth, mean/median/maximum process length, and mean outgrowth intensity (P < 0.05). The differences in damage among drugs reflect differences in their mechanisms of action and clinical CIPN manifestations. We show the potential of the model for gene perturbation studies by demonstrating decreased expression of TUBB2A results in significantly increased sensitivity of neurons to paclitaxel (0.23 ± 0.06 decrease in total neurite outgrowth, P = 0.011). The variance in several neurite outgrowth and apoptotic phenotypes upon treatment with one of the neurotoxic drugs is significantly greater between than within neurons derived from four different individuals (P < 0.05), demonstrating the potential of iPSC-derived neurons as a genetically diverse model for CIPN. The human neuron model will allow both for mechanistic studies of specific genes and genetic variants discovered in clinical studies and for screening of new drugs to prevent or treat CIPN.

Pharmacokinetics and pharmacogenomics of daunorubicin in children: a report from the Children's Oncology Group.

PURPOSE: We explored the impact of obesity, body composition, and genetic polymorphisms on the pharmacokinetics (PK) of daunorubicin in children with cancer. PATIENTS AND METHODS: Patients ≤21 years receiving daunorubicin as an infusion of any duration <24 h for any type of cancer were eligible. Plasma drug concentrations were measured by high-performance liquid chromatography. Body composition was measured by dual-energy X-ray absorptiometry. Obesity was defined as a BMI >95% for age or as body fat >30%. NONMEM was used to perform PK model fitting. The Affymetrix DMET chip was used for genotyping. The impact of genetic polymorphisms was investigated using SNP/haplotype association analysis with estimated individual PK parameters. RESULTS: A total of 107 subjects were enrolled, 98 patients had PK sampling, and 50 patients underwent DNA analysis. Population estimates for daunorubicin clearance and volume of distribution were 116 L/m(2)/h ± 14% and 68.1 L/m(2) ± 24%, respectively. Apparent daunorubicinol clearance and volume of distribution were 26.8 L/m(2)/h ± 5.6% and 232 L/m(2) ± 10%, respectively. No effect of body composition or obesity was observed on PK. Forty-four genes with variant haplotypes were tested for association with PK. FMO3-H1/H3 genotype was associated with lower daunorubicin clearance than FMO3-H1/H1, p = 0.00829. GSTP1*B/*B genotype was also associated with lower daunorubicin clearance compared to GSTP1*A/*A, p = 0.0347. However, neither of these associations was significant after adjusting for multiple testing by either Bonferroni or false discovery rate correction. CONCLUSIONS: We did not detect an effect of body composition or obesity on daunorubicin PK. We found suggestive associations between FMO3 and GSTP1 haplotypes with daunorubicin PK that could potentially affect efficacy and toxicity.