Predicted expression of genes involved in the thiopurine metabolic pathway and azathioprine discontinuation due to myelotoxicity

TPMT and NUDT15 variants explain less than 25% of azathioprine‐associated myelotoxicity. There are 25 additional genes in the thiopurine pathway that could also contribute to azathioprine myelotoxicity. We hypothesized that among TPMT and NUDT15 normal metabolizers, a score combining the genetically predicted expression of other proteins in the thiopurine pathway would be associated with a higher risk for azathioprine discontinuation due to myelotoxicity. We conducted a retrospective cohort study of new users of azathioprine who were normal TPMT and NUDT15 metabolizers. In 1201 White patients receiving azathioprine for an inflammatory disease, we used relaxed Least Absolute Shrinkage and Selection Operator (LASSO) regression to select genes that built a score for discontinuing azathioprine due to myelotoxicity. The score incorporated the predicted expression of AOX1 and NME1. Patients in the highest score tertile had a higher risk of discontinuing azathioprine compared to those in the lowest tertile (hazard ratio [HR] = 2.15, 95% confidence interval [CI] = 1.11–4.19, p = 0.024). Results remained significant after adjusting for a propensity score, including sex, tertile of calendar year at initial dose, initial dose, age at baseline, indication, prior TPMT testing, and the first 10 principal components of the genetic data (HR = 2.11, 95% CI = 1.08–4.13, p = 0.030). We validated the results in a cohort (N = 517 non‐White patients and those receiving azathioprine to prevent transplant rejection) that included all other patients receiving azathioprine (HR = 2.00, (95% CI = 1.09–3.65, p = 0.024). In conclusion, among patients who were TPMT and NUDT15 normal metabolizers, a score combining the predicted expression of AOX1 and NME1 was associated with an increased risk for discontinuing azathioprine due to myelotoxicity.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Azathioprine is an immunosuppressant that causes myelotoxicity in some people. Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines provide azathioprine dosing recommendations based on TPMT and NUDT15 genotype; however, these genotypes explain only 25% of azathioprine‐induced myelotoxicity.

• WHAT QUESTION DID THIS STUDY ADDRESS?

The aim of this study was to determine if a risk score composed of the genetically predicted expression of genes that encode proteins in the thiopurine pathway within the liver tissue would be associated with azathioprine discontinuation attributed to myelotoxicity.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study showed that a risk score composed of genetically predicted risk expression of AOX1 and NME1 is associated with azathioprine discontinuation due to myelotoxicity.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Having a risk score for discontinuation composed of the genetically predicted expression of NME1 and AOX1 could help discriminate patients at high risk of discontinuing azathioprine due to hematologic side effects in people who are normal TPMT and NUDT15 metabolizers.     

AMP-18,一种新发现的胃黏膜保护因子

AMP-18是一种新发现的由胃腺体上皮细胞合成的小分子蛋白质,独特表达于胃黏膜,机体其他部位少见,胃癌组织中表达缺失．AMP-18 由185个氨基酸组成,除去N端信号肽(20个氨基酸)后大小约18 ku,第54-150个氨基酸组成高度保守的结构域(BRICHOS区域)承担主要的生理功能．AMP-18由胃腺体上皮细胞以胞吐的方式分泌到胃黏液中,他的合成和分泌与个体生长发育有关,并受福斯高林、吲哚美辛、地塞米松等药物的影响．目前发现 AMP-18的生理功能主要有促进胃黏膜上皮细胞的有丝分裂,促进细胞的迁徙,促胃肠黏膜损伤的修复,保持胃肠黏膜的完整等．     

Power output during women’s World Cup road cycle racing

Little information exists on the power output demands of competitive women’s road cycle racing. The purpose of our investigation was to document the power output generated by elite female road cyclists who achieved success in FLAT and HILLY World Cup races. Power output data were collected from 27 top-20 World Cup finishes (19 FLAT and 8 HILLY) achieved by 15 nationally ranked cyclists (mean ± SD; age: 24.1±4.0 years; body mass: 57.9±3.6 kg; height: 168.7±5.6 cm; 63.6±2.4 mL kg⁻¹ min⁻¹; peak power during graded exercise test (GXT_{peak power}): 310±25 W). The GXT determined GXT_{peak power}, lactate threshold (LT) and anaerobic threshold (AT). Bicycles were fitted with SRM powermeters, which recorded power (W), cadence (rpm), distance (km) and speed (km h⁻¹). Racing data were analysed to establish time in power output and metabolic threshold bands and maximal mean power (MMP) over different durations. When compared to HILLY, FLAT were raced at a similar cadence (75±8 vs. 75±4 rpm, P=0.93) but higher speed (37.6±2.6 vs. 33.9±2.7 km h⁻¹, P=0.008) and power output (192±21 vs. 169±17 W, P=0.04; 3.3±0.3 vs. 3.0±0.4 W kg⁻¹, P=0.04). During FLAT races, riders spent significantly more time above 500 W, while greater race time was spent between 100 and 300 W (LT-AT) for HILLY races, with higher MMPs for 180–300 s. Racing terrain influenced the power output profiles of our internationally competitive female road cyclists. These data are the first to define the unique power output requirements associated with placing well in both flat and hilly women’s World Cup cycling events.     

Spectrally opponent inputs to the human luminance pathway: slow +M and −L cone inputs revealed by intense long-wavelength adaptation

The nature of the inputs to achromatic luminance flicker perception was explored psychophysically by measuring middle- (M-) and long-wavelength-sensitive (L-) cone modulation sensitivities, M- and L-cone phase delays, and spectral sensitivities as a function of temporal frequency. Under intense long-wavelength adaptation, the existence of multiple luminance inputs was revealed by substantial frequency-dependent changes in all three types of measure. Fast (f) and slow (s) M-cone input signals of the same polarity (+sM and +fM) sum at low frequencies, but then destructively interfere near 16 Hz because of the delay between them. In contrast, fast and slow L-cone input signals of opposite polarity (−sL and +fL) cancel at low frequencies, but then constructively interfere near 16 Hz. Although these slow, spectrally opponent luminance inputs (+sM and −sL) would usually be characterized as chromatic, and the fast, non-opponent inputs (+fM and +fL) as achromatic, both contribute to flicker photometric nulls without producing visible colour variation. Although its output produces an achromatic percept, the luminance channel has slow, spectrally opponent inputs in addition to the expected non-opponent ones. Consequently, it is not possible in general to silence this channel with pairs of 'equiluminant' alternating stimuli, since stimuli equated for the non-opponent luminance mechanism (+fM and +fL) may still generate spectrally opponent signals (+sM and +sL).     

Measurement and prediction of METs during household activities in 35- to 45-year-old females

This study determined whether four self-paced household tasks, conducted in the subjects homes and a standardised laboratory environment, were performed at a moderate intensity [3–6 metabolic equivalents (METs)] in a representative sample of thirty-six 35- to 45-year-old females. Energy expenditure was also predicted via indirect methods. Self-paced energy expenditure during sweeping, window cleaning, vacuuming and mowing was measured using the Douglas bag technique. Heart rate, respiratory frequency, Computer Science Applications (CSA) movement counts (hip and wrist), Borg rating of perceived exertion and Quetelets index were also recorded as potential predictors of energy expenditure. While the four activities were performed at mean intensities 3.0 METs in both the home and laboratory, all comparisons between these two environments were statistically significant (P<0.001). The 95% confidence intervals (CIs) for the home and laboratory prediction equations were ±1.1 METs and ±1.0 MET, respectively. These data suggest that the aforementioned household chores can contribute to the 30 min·day^–1 of moderate-intensity activity required to confer health benefits. However, the substantial between-subject variability in energy expenditure resulted in some persons performing these tasks at a light intensity (<3.0 METs). The significant MET differences between the home and laboratory emphasise the effects of environment and terrain and the mental approach to a task on self-paced energy expenditure. Considering the means for the five activities ranged from 3.1 METs to 6.0 METs, the 95% CIs for the regression equations lack predictive precision.     

Identification of a novel HLA-DQA1 null allele, DQA1*0403N, from an East African woman

We report a novel DQA1 allele (DQA1*0403N) identified during sequence-based HLA-DQA1 typing of a Kenyan population. The new allele is identical to DQA1*0401 at exon 2 except for a single-nucleotide substitution at codon 53, changing it from lysine to a stop codon (CAA-->TAA). The substitution at codon 53 was confirmed by sequencing two separate polymerase chain reaction products and by sequencing multiple clones obtained following TOPO-TA cloning. The resulting stop codon at position of codon 53 in exon 2 is predicted to produce a non-functional DQA1 alpha-chain. The new allele has been named by the WHO nomenclature committee as DQA1*0403N. This is the first report of a null allele detected in the DQA1 gene.     

Characterization of the human jumonji gene

While constructing a cDNA library of human embryos, we have isolated a clone homologous to jumonji, a mouse gene required for neural tube formation. We have determined the complete coding sequence of the human homologue (JMJ) and deduced the amino acid sequence of the putative protein. We show here that human and mouse jumonji putative proteins are homologous and present 90% identity. During human embryogenesis, JMJ mRNAs are predominantly expressed in neurons and particularly in dorsal root ganglion cells. They are also expressed in neurons of human adult cerebral cortex. In view of these observations, we propose JMJ as a candidate gene for developmental defects of the central nervous system in the human. The human JMJ gene maps at position 6p24-6p23.      

Screening for proteins with polyglutamine expansions in autosomal dominant cerebellar ataxias

Expansion of trinucleotide CAG repeats coding for polyglutamine has been implicated in five neurodegenerative disorders, including spinocerebellar ataxia (SCA) 1 and SCA3 or Machado-Joseph disease (SCA3/MJD), two forms of type I autosomal dominant cerebellar ataxias (ADCA). Using the 1C2 antibody which specifically recognizes large polyglutamine tracts, particularly those that are expanded, we recently reported the detection of proteins with pathological glutamine expansions in lymphoblasts from another form of ADCA type I, SCA2, as well as from patients presenting with the distinct phenotype of ADCA type II. We now have screened a large series of patients with ADCA or isolated cases with cerebellar ataxia, for the presence of proteins with polyglutamine expansions. A 150 kDa SCA2 protein was detected in 16 out of 40 families with ADCA type I. This corresponds to 24% of all ADCA type I families, which is much more frequent than SCA1 in this series of patients (13%). The signal intensity of the SCA2 protein was negatively correlated to age at onset, as expected for an expanded and unstable trinucleotide repeat mutation. The disease segregated with markers closely linked to the SCA2 locus in all identified SCA2 families. In addition, a specific 130 kDa protein, which segregated with the disease, was detected in lymphoblasts of patients from nine families with ADCA type II. It was also visualized in the cerebral cortex of one of the patients, demonstrating its translation in the nervous system. Finally, no new disease-related proteins containing expanded polyglutamine tracts could be detected in lymphoblasts from the remaining patients with ADCA or isolated cases with cerebellar ataxia.      

Molecular evidence for zoonotic transmission of an emergent, highly pathogenic Campylobacter jejuni clone in the United States

Campylobacter jejuni is a major zoonotic pathogen. A highly virulent, tetracycline-resistant C. jejuni clone (clone SA) has recently emerged in ruminant reservoirs and has become the predominant cause of sheep abortion in the United States. To determine whether clone SA is associated with human disease, we compared the clinical isolates of clone SA from sheep abortions with the human isolates of the PulseNet National Campylobacter databases at the CDC and the FDA using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and serotyping. The combined SmaI and KpnI PFGE pattern designations of clone SA from sheep were indistinguishable from those of 123 (9.03%) human C. jejuni isolates (total, 1,361) in the CDC database, among which 56 were associated with sporadic infections and 67 were associated with outbreaks that occurred in multiple states from 2003 to 2010. Most of the outbreaks were attributed to raw milk, while the sources for most of the sporadic cases were unknown. All clone SA isolates examined, including PFGE-matched human isolates, belong to sequence type 8 (ST-8) by MLST and serotype HS:1,8, further indicating the clonality of the related isolates from different host species. Additionally, C. jejuni clone SA was identified in raw milk, cattle feces, the feces and bile of healthy sheep, and abortion cases of cattle and goats, indicating the broad distribution of this pathogenic clone in ruminants. These results provide strong molecular and epidemiological evidence for zoonotic transmission of this emergent clone from ruminants to humans and indicate that C. jejuni clone SA is an important threat to public health.     

Substantial intrapatient differences in the breadth and specificity of HIV-specific CD8+ T-cell interferon-gamma and proliferation responses

HIV vaccine design and evaluation require a better understanding of protective immune responses. HIV-specific CD8+ T-cell responses have been characterized extensively using interferon-gamma (IFN-gamma) enzyme-linked immunosorbent spot (ELISPOT) assays, which do not always correlate with control of viral replication or disease progression. Alternative aspects of CD8+ T-cell responses, in particular those associated with a central memory (Tcm) phenotype, may be more protective against disease progression. To determine the extent that the breadth and specificity of HIV-specific CD8+ T-cell responses differ based on immunological readout, we screened in HIV-infected Kenyan sex workers for responses to HIV Env using IFN-gamma ELISPOT and 6-day carboxyfluorescein succinimidyl ester-based proliferation assays. This comparison revealed substantial differences in the epitopes recognized when the assay readout was IFN-gamma versus proliferation. Although 24 and 41 IFN-gamma and proliferative responses were identified, overlapping specificity was observed for only 5 responses. Breadth also differed between assays in several patients. Env-specific IFN-gamma breadth was found to correlate inversely with CD4 count (r = -0.66, P = 0.005), although this was not the case for proliferation. These data suggest that efforts to define HIV-specific CD8+ T-cell responses may need to be revisited using additional immunological readouts.