Variability of cytokine gene expression in intestinal tissue and the impact of normalization with the use of reference genes

Effect of Aspirin on the Intestinal Response to a Necrotic Enteritis Challenge

The effect of aspirin on intestinal lesions was evaluated in birds undergoing an experimental challenge with Clostridium perfringens as part of a model for inducing subclinical necrotic enteritis (SNE). Broilers were raised on clean wood shavings and randomly assigned to three treatments: Uninfected (U), Infected (I), and Infected + Aspirin (I+A; 0.025% acetylsalicylic acid in drinking water during days 21-25). Birds in the I and I+A groups were gavaged with Eimeria maxima on day 18 and their feed was inoculated with C. perfringens (1 × 10⁹ CFU/bird) during days 23-25. On day 26, birds were euthanatized, intestinal lesions were evaluated, and intestinal tissue was collected for qPCR assessment of genes thought to be involved in the immune response to SNE: IL-1β, IL-10, MMP-2, and MMP-7. Birds in the I+A group had more-severe and numerous lesions compared to the I group. For all genes except MMP-2, expression was upregulated in the I group compared to the U group, but did not differ between the I and I+A groups. These results indicate that aspirin exacerbated the intestinal lesions associated with this disease. Aspirin could play a role in the development of a reliable and consistent model for the induction of necrotic enteritis under experimental settings.

Increased expression of IL-32 correlates with IFN-γ, Th1 and Tc1 in virologically suppressed HIV-1-infected patients

Following recent attention focused on IL-32 as an important component involved in the inflammatory cytokine network, we speculated that IL-32's action on IFN-γ and IFN-γ secreting T cell subsets may help sustain the immune activation and dysregulation found in patients with HIV-1 achieving viral suppression. To explore this hypothesis, transcript levels of IL-32 and IFN-γ were evaluated in PBMC from 139 virologically suppressed HIV-1-infected patients and from 63 healthy individuals by Real Time RT-PCR assays. IL-32 and IFN-γ mRNA levels were also analyzed in CD4+ T cells, CD14+ monocytes and lamina propria lymphocytes (LPL) of the gut district in a subgroup of HIV-1-infected subjects. IFN-γ secreting CD4+ (Th1) and CD8+ (Tc1) T cell subset frequencies were evaluated in LPL by multiparametric flow cytometry. Gene expression results revealed that IL-32 and IFN-γ levels in PBMC from HIV-1-positive patients were significantly elevated compared to those from healthy donors, correlated with each other and increased with patient age. Both IL-32 and IFN-γ genes were also more strongly expressed in CD4+ T cells than in CD14+ monocytes. By contrast, IL-32 levels in LPL were comparable to those measured in PBMC, while IFN-γ levels were higher in PBMC than those in LPL. Negative correlations were found between IL-32 levels and the frequencies of Th1 and Tc1 subsets in gut mucosa. Collectively, our results provide the first evidence that IL-32 levels remain elevated in treated HIV-1-infected patients and correlate with IFN-γ, Th1 and Tc1 subsets.

A Pilot Study of the Immunologic, Virologic, and Pathologic Consequences of Intra-anal 5% Imiquimod in HIV-1-Infected Men With High-Grade Squamous Intraepithelial Lesions

BACKGROUND

Imiquimod can be used to treat internal anal high-grade squamous intraepithelial lesions. In HIV-1-infected individuals there is a theoretical concern for increased HIV replication in anorectal tissue secondary to imiquimod-induced mucosal inflammation.

OBJECTIVE

The purpose of this study was to assess local virologic, immunologic, and pathologic effects of imiquimod treatment in HIV-infected individuals.

DESIGN

This was a pilot study at a single academic center.

SETTINGS

The study was conducted at the University of Pittsburgh Anal Dysplasia Clinic.

PATIENTS

HIV-1-infected individuals with biopsy-confirmed internal anal high-grade squamous intraepithelial lesions were included.

INTERVENTION

Imiquimod cream was prescribed for intra-anal use 3 times per week for 9 weeks.

MAIN OUTCOME MEASURES

Anal human papillomavirus typing, anal and rectal tissue HIV-1 RNA and DNA quantification, cytokine gene expression, and anal histology were measured.

RESULTS

Nine evaluable participants (1 participant was lost to follow-up) were all white men with a median age of 46 years (interquartile range = 12 y) and a median CD4 T-cell count of 480 cells per cubic millimeter (interquartile range = 835). All were taking antiretroviral therapy, and 7 of 9 had HIV-1 RNA <50 copies per milliliter. The median dose of imiquimod used was 27.0 (interquartile range = 3.5), and there was a median of 11 days (interquartile range = 10 d) from last dose to assessment. There was no progression to cancer, no significant change in the number of human papillomavirus types detected, and no significant change in quantifiable cytokines/HIV-1 RNA or DNA levels in anal or rectal tissue. Seven (35%) of 20 high-grade lesions resolved to low-grade squamous intraepithelial lesions.

LIMITATIONS

The study was limited by the small number of participants and variable time to final assessment.

CONCLUSIONS

Intra-anal imiquimod showed no evidence of immune activation or increase in HIV-1 viral replication in anal and rectal tissue and confirmed efficacy for intra-anal high-grade squamous intraepithelial lesion treatment morbidity. See Video Abstract at http://links.lww.com/DCR/A498.

Identification of Novel Reference Genes Suitable for qRT-PCR Normalization with Respect to the Zebrafish Developmental Stage

Reference genes used in normalizing qRT-PCR data are critical for the accuracy of gene expression analysis. However, many traditional reference genes used in zebrafish early development are not appropriate because of their variable expression levels during embryogenesis. In the present study, we used our previous RNA-Seq dataset to identify novel reference genes suitable for gene expression analysis during zebrafish early developmental stages. We first selected 197 most stably expressed genes from an RNA-Seq dataset (29,291 genes in total), according to the ratio of their maximum to minimum RPKM values. Among the 197 genes, 4 genes with moderate expression levels and the least variation throughout 9 developmental stages were identified as candidate reference genes. Using four independent statistical algorithms (delta-CT, geNorm, BestKeeper and NormFinder), the stability of qRT-PCR expression of these candidates was then evaluated and compared to that of actb1 and actb2, two commonly used zebrafish reference genes. Stability rankings showed that two genes, namely mobk13 (mob4) and lsm12b, were more stable than actb1 and actb2 in most cases. To further test the suitability of mobk13 and lsm12b as novel reference genes, they were used to normalize three well-studied target genes. The results showed that mobk13 and lsm12b were more suitable than actb1 and actb2 with respect to zebrafish early development. We recommend mobk13 and lsm12b as new optimal reference genes for zebrafish qRT-PCR analysis during embryogenesis and early larval stages.