Race- and gender-related variation in NKp46 expression associated with differential anti-HCV immunity

Division of Gastroenterology and Hepatology, Hepatitis C Center, Department of Medicine, University of Colorado Denver, Aurora, CO
Hepatology (Impact Factor: 11.06). 10/2012; 56(4):1214-22. DOI: 10.1002/hep.25771
Source: PubMed


Major racial and gender differences have been documented in the natural history and treatment responses of chronic hepatitis C virus (HCV) infection; however, distinct mechanisms have remained enigmatic. We hypothesized that racial- and gender-related differences in natural killer (NK) cell populations may explain altered natural history and treatment responses. Our study cohort consisted of 29 African-American (AA; 55% male) and 29 Caucasian-American (CA; 48% male) healthy uninfected control subjects. Multiparameter flow cytometric analysis was used to characterize levels, phenotype with respect to 14 NK receptors, and lymphokine-activated killing (LAK) function. Gene expression was assessed by real-time reverse-transcriptase polymerase chain reaction after 6-hour in vitro stimulation with Toll-like receptor (TLR) ligands. The ability to control HCV infection was assessed in the Huh-7.5/JFH-1 coculture system. NK expression of natural cytotoxicity receptor NKp46 was strongly associated with CA race and female gender and correlated positively with LAK activity (P = 0.0054). NKp46(high) NKs were more efficient at controlling HCV than their NKp46(low) counterparts (P < 0.001). Similarly, ligation of NKp46 on isolated NK cells resulted in a significant reduction in the HCV copy number detected in Huh-7.5/JFH-1 coculture (multiplicity of infection: 0.01) at an effector:target ratio of 5:1 (P < 0.005). After TLR stimulation, genes involved in cytotoxicity, but not cytokine genes, were significantly up-regulated in NKp46(high) NKs. Cytokine stimulation (interleukin [IL]-12 and IL-15) demonstrated that NKp46(high) NK cells have significantly higher interferon-gamma production than NKp46(low) cells. TLR stimulation significantly induced degranulation as well as tumor necrosis factor alpha (TNF-α)-related apoptosis-inducing ligand, Fas, and TNF-α protein expression in NKp46(high) NKs. NKp46 ligand was induced on HCV-infected hepatocytes. Conclusions: NKp46 expression may contribute to differential HCV responses. NKp46 expression correlates with anti-HCV activity in vitro and thus may prove to be a useful therapeutic target. (HEPATOLOGY 2012).


Available from: Lucy Golden-Mason
  • Source
    • "Overall, both genders of mice showed similar rates of persistent infection, but liver pathology progresses slightly faster, if any, in males (Supplementary information, Table S9). Whether sex hormones45, IL-28B polymorphism46, and natural killer p46 expression47, as suggested in the gender differences in humans, play a role in this mouse model remains to be investigated. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The majority of hepatitis C virus (HCV) infection develops chronic infection, which causes steatosis, cirrhosis and hepatocellular carcinoma. However, understanding HCV chronicity and pathogenesis is hampered by its narrow host range, mostly restricted to human and chimpanzee. Recent endeavour to infect a variety of humanized mice has not been able to achieve persistent HCV infection unless the essential innate immune responsive genes are knocked out. Nevertheless, such immune-compromised humanized mice still lacked HCV infection-induced hepatopathogenesis. Here we report that transgenic mice in ICR background harboring both human CD81 and occludin genes (C/O(Tg)) are permissive to HCV infection at a chronicity rate comparable to humans. In this mouse model, HCV accomplishes its replication cycle, leading to sustained viremia and infectivity for more than 12 months post infection with expected fibrotic and cirrhotic progression. Host factors favorable for HCV replication, and inadequate innate immune-response may contribute to the persistence. Lastly, NS3/4 protease inhibitor telaprevir can effectively inhibit de novo RNA synthesis and acute HCV infection of C/O(Tg) mice. Thus, chronic HCV infection with complete replication cycle and hepatopathologic manifestations is recapitulated, for the first time, in immune-competent mice. This model will open a new venue to study the mechanisms of chronic hepatitis C and develop better treatments.Cell Research advance online publication 26 August 2014; doi:10.1038/cr.2014.116.
    Cell Research 08/2014; 24(9). DOI:10.1038/cr.2014.116 · 12.41 Impact Factor
  • Source
    • "Chronic viral infections including HCV can modulate expression of inhibitory and activating NKRs which control the activity of NK cells [16], [27], [30], [42]. However, little is known of the expression of these receptors in the acute setting; therefore, we examined the phenotype of NK cells in our patient cohort to determine whether altered NKR expression was associated with outcome of acute HCV infection. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Hepatitis C viral (HCV) proteins, including core, demonstrate immuno-modulatory properties; however, the effect of extracellular core on natural killer (NK) cells has not previously been investigated. Aims: To characterise NKs in acute HCV infection over time, and, to examine the effect of exogenous HCV-core protein on NK cell phenotype and function. Methods: Acute HCV patients (n = 22), including 10 subjects who spontaneously recovered, were prospectively studied. Flow-cytometry was used to measure natural cytotoxicity and to phenotype NKs directly ex vivo and after culture with HCV-core protein. Microarray analysis was used to identify pathways involved in the NK cell response to exogenous HCV-core. Results: Direct ex vivo analysis demonstrated an increased frequency of immature/regulatory CD56(bright) NKs early in acute HCV infection per se which normalized with viral clearance. Natural cytotoxicity was reduced and did not recover after viral clearance. There was a statistically significant correlation between the frequency of CD56(bright) NKs and circulating serum levels of HCV core protein. In vitro culture of purified CD56(bright) NK cells with HCV-core protein in the presence of IL-15 maintained a significant proportion of NKs in the CD56(bright) state. The in vitro effect of core closely correlates with NK characteristics measured directly ex vivo in acute HCV infection. Pathway analysis suggests that HCV-core protein attenuates NK interferon type I responses. Conclusions: Our data suggest that HCV-core protein alters NK cell maturation and may influence the outcome of acute infection.
    PLoS ONE 07/2014; 9(7):e103219. DOI:10.1371/journal.pone.0103219 · 3.23 Impact Factor
  • Source
    • "As expected, the three retinal samples used for our analysis showed variability with regards to alternative splicing. This is likely a factor of gender, age, and technical factors such as post-mortem time to RNA isolation [62,63]. Among the novel events in the RNA capture set, nearly 7,000 were common within the three samples (Figure  7B). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The retina is a complex tissue comprised of multiple cell types that is affected by a diverse set of diseases that are important causes of vision loss. Characterizing the transcripts, both annotated and novel, that are expressed in a given tissue has become vital for understanding the mechanisms underlying the pathology of disease. We sequenced RNA prepared from three normal human retinas and characterized the retinal transcriptome at an unprecedented level due to the increased depth of sampling provided by the RNA-seq approach. We used a non-redundant reference transcriptome from all of the empirically-determined human reference tracks to identify annotated and novel sequences expressed in the retina. We detected 79,915 novel alternative splicing events, including 29,887 novel exons, 21,757 3[prime] and 5[prime] alternate splice sites, and 28,271 exon skipping events. We also identified 116 potential novel genes. These data represent a significant addition to the annotated human transcriptome. For example, the novel exons detected increase the number of identified exons by 3%. Using a high-throughput RNA capture approach to validate 14,696 of these novel transcriptome features we found that 99% of the putative novel events can be reproducibly detected. Further, 15-36% of the novel splicing events maintain an open reading frame, suggesting they produce novel protein products. To our knowledge, this is the first application of RNA capture to perform large-scale validation of novel transcriptome features. In total, these analyses provide extensive detail about a previously uncharacterized level of transcript diversity in the human retina.
    BMC Genomics 07/2013; 14(1):486. DOI:10.1186/1471-2164-14-486 · 3.99 Impact Factor
Show more