Project description:Not all patients with nerve injury develop neuropathic pain. The extent of nerve damage and age at the time of injury are two of the few risk factors identified to date. In addition, preclinical studies show that neuropathic pain variance is heritable. To define such factors further, we performed a large-scale gene profiling experiment which plotted global expression changes in the rat dorsal root ganglion in three peripheral neuropathic pain models. This resulted in the discovery that the potassium channel alpha subunit KCNS1, involved in neuronal excitability, is constitutively expressed in sensory neurons and markedly downregulated following nerve injury. KCNS1 was then characterized by an unbiased network analysis as a putative pain gene, a result confirmed by single nucleotide polymorphism association studies in humans. A common amino acid changing allele, the 'valine risk allele', was significantly associated with higher pain scores in five of six independent patient cohorts assayed (total of 1359 subjects). Risk allele prevalence is high, with 18-22% of the population homozygous, and an additional 50% heterozygous. At lower levels of nerve damage (lumbar back pain with disc herniation) association with greater pain outcome in homozygote patients is P = 0.003, increasing to P = 0.0001 for higher levels of nerve injury (limb amputation). The combined P-value for pain association in all six cohorts tested is 1.14 E-08. The risk profile of this marker is additive: two copies confer the most, one intermediate and none the least risk. Relative degrees of enhanced risk vary between cohorts, but for patients with lumbar back pain, they range between 2- and 3-fold. Although work still remains to define the potential role of this protein in the pathogenic process, here we present the KCNS1 allele rs734784 as one of the first prognostic indicators of chronic pain risk. Screening for this allele could help define those individuals prone to a transition to persistent pain, and thus requiring therapeutic strategies or lifestyle changes that minimize nerve injury. Microarrays were run on mRNA extracted from adult rat L4 and L5 DRGs cells after 3,7,21,40 hours after three different sciatic nerve lesions [Spared Nerve Injury (SNI); Chronic Constriction Injury (CCI); Spinal Nerve Ligation (Ch) with Sham controls (SH)].
Project description:Not all patients with nerve injury develop neuropathic pain. The extent of nerve damage and age at the time of injury are two of the few risk factors identified to date. In addition, preclinical studies show that neuropathic pain variance is heritable. To define such factors further, we performed a large-scale gene profiling experiment which plotted global expression changes in the rat dorsal root ganglion in three peripheral neuropathic pain models. This resulted in the discovery that the potassium channel alpha subunit KCNS1, involved in neuronal excitability, is constitutively expressed in sensory neurons and markedly downregulated following nerve injury. KCNS1 was then characterized by an unbiased network analysis as a putative pain gene, a result confirmed by single nucleotide polymorphism association studies in humans. A common amino acid changing allele, the 'valine risk allele', was significantly associated with higher pain scores in five of six independent patient cohorts assayed (total of 1359 subjects). Risk allele prevalence is high, with 18-22% of the population homozygous, and an additional 50% heterozygous. At lower levels of nerve damage (lumbar back pain with disc herniation) association with greater pain outcome in homozygote patients is P = 0.003, increasing to P = 0.0001 for higher levels of nerve injury (limb amputation). The combined P-value for pain association in all six cohorts tested is 1.14 E-08. The risk profile of this marker is additive: two copies confer the most, one intermediate and none the least risk. Relative degrees of enhanced risk vary between cohorts, but for patients with lumbar back pain, they range between 2- and 3-fold. Although work still remains to define the potential role of this protein in the pathogenic process, here we present the KCNS1 allele rs734784 as one of the first prognostic indicators of chronic pain risk. Screening for this allele could help define those individuals prone to a transition to persistent pain, and thus requiring therapeutic strategies or lifestyle changes that minimize nerve injury.
Project description:A novel missense mutation has been identified in a human pain-insensitive family in the gene ZFHX2. We modelled this mutation in mice by changing the orthologous amino acid and carried out pain behaviour tests in mutant BAC transgenic mice. These showed a phenotype of hyposensitivity to noxious thermal stimuli. In this experiment, we generated a stable cell line expressing the mutant human ZFHX2 protein in order to identify chromatin binding sites. Complementary microarray data from ZFHX2 mutant mice were also deposited at ArrayExpress under accession number E-MTAB-5650 ( https://www.ebi.ac.uk/arrayexpress/experiments/E-MTAB-5650 ).
Project description:Goals of the Study:; 1. Assess the scope of arginine-responsive hepatic gene expression using in vitro rat models. 2. Compare normal and tumorigenic cells; 3. Identify potentially novel genes and pathways that may be subject to amino acid (arginine) regulation; Background: We previously reported that mRNA levels of the tumor associated glycoprotein amino acid transporter TA1/LAT1/ CD98 light chain arginine increase in normal hepatic cells under low arginine conditions while levels are constitutive and high in hepatic tumor cells. This suggested LAT1 amino acid response was associated with the normal hepatic phenotype and lost in carcinogenesis and may impact cell growth and survival in the tumor microenvironment. We sought to investigate how many and what types of genes are responsive to a change in arginine levels over 18 hrs using an in vitro model system. Experimental design:; Differential gene expression was determined by microarrays using samples from triplicates of normal and transformed cells subjected to 18 hour arginine-deprivation compared to controls