Serum Lipid Metabolic Derangement is Associated with Disease Progression During Chronic HBV Infection.

BACKGROUND: To investigate the relationship between serum lipid levels and disease progression during chronic hepatitis B virus infection. METHODS: We selected 73 healthy controls and 163 patients with chronic HBV infection as the study subjects. The chronic HBV infection patients were divided into the HBV carrier group (74 patients), chronic hepatitis B group (71 patients), and liver cirrhosis group (21 patients). The age, gender, body mass index, blood lipid index, liver function index, and HBV DNA levels of all participants were tested and recorded. A t-test or the Mann-Whitney U test was used to compare the data between two groups; data from multiple groups were compared using one-way ANOVA or the Kruskal-Wallis Test. RESULTS: We observed that the serum HDL cholesterol (1.00 ± 0.30 mmol/L in the HBV-infected group, 1.29 ± 0.23 mmol/L in the control group) and APOA (1.29 ± 0.35 mmol/L, 1.36 ± 0.21 mmol/L, respectively) concentrations were significantly lower in the HBV-infected group than in the control group (p < 0.05). As the disease progressed, the blood lipid and lipoprotein values were significantly lower in the cirrhosis group TC (3.26 ± 1.00 mmol/L), HDL cholesterol (0.77 ± 0.33 mmol/L), LDL cholesterol (2.09 ± 0.62 mmol/L), and APOB (0.57 ± 0.18 mmol/L) compared with the control group, the carrier group, and the chronic hepatitis B group (p < 0.05). The serum HBV DNA level was significantly, positively correlated with the blood HDL concentration (carrier group R = 0.340, p = 0.02; chronic hepatitis B group R = 0.329, p = 0.014). There was no correlation between the HBV DNA and lipid levels in patients with cirrhosis. CONCLUSIONS: Serum lipid metabolic derangement was associated with disease progression during chronic HBV infection. Liver function and blood lipid levels were significantly lower in patients with hepatitis B-related cirrhosis.

Serum interleukin-34 level can be an indicator of liver fibrosis in patients with chronic hepatitis B virus infection.

AIM: To investigate whether serum interleukin (IL)-34 levels are correlated with hepatic inflammation and fibrosis in patients with chronic hepatitis B virus (HBV) infection. METHODS: In this study, serum IL-34 levels were assessed by enzyme-linked immunosorbent assay in 19 healthy controls and 175 patients with chronic HBV infection undergoing biopsy. The frequently used serological markers of liver fibrosis were based on laboratory indexes measured at the Clinical Laboratory of the Second Affiliated Hospital of Anhui Medical University. Liver stiffness was detected by transient elastography with FibroTouch. The relationships of non-invasive makers of liver fibrosis and IL-34 levels with inflammation and fibrosis were analyzed. The diagnostic value of IL-34 and other liver fibrosis makers were evaluated using areas under the receiver operating characteristic curves, sensitivity and specificity. RESULTS: Serum IL-34 levels were associated with inflammatory activity in the liver, and IL-34 levels differed among phases of chronic HBV infection (P = 0.001). By comparing serum IL-34 levels among patients with various stages of liver fibrosis determined by liver biopsy, we found that IL-34 levels ≥ 15.83 pg/mL had a high sensitivity of 86.6% and a specificity of 78.7% for identifying severe fibrosis (S3-S4). Furthermore, we showed that IL-34 is superior to the fibrosis-4 score, one of the serum makers of liver fibrosis, in identifying severe liver fibrosis and early cirrhosis in patients with HBV-related liver fibrosis in China. CONCLUSION: Our results indicate that IL-34, a cytokine involved in the induction of activation of profibrogenic macrophages, can be an indicator of liver inflammation and fibrosis in patients with chronic HBV infection.

Rapid evolution and copy number variation of primate RHOXF2, an X-linked homeobox gene involved in male reproduction and possibly brain function.

BACKGROUND: Homeobox genes are the key regulators during development, and they are in general highly conserved with only a few reported cases of rapid evolution. RHOXF2 is an X-linked homeobox gene in primates. It is highly expressed in the testicle and may play an important role in spermatogenesis. As male reproductive system is often the target of natural and/or sexual selection during evolution, in this study, we aim to dissect the pattern of molecular evolution of RHOXF2 in primates and its potential functional consequence. RESULTS: We studied sequences and copy number variation of RHOXF2 in humans and 16 nonhuman primate species as well as the expression patterns in human, chimpanzee, white-browed gibbon and rhesus macaque. The gene copy number analysis showed that there had been parallel gene duplications/losses in multiple primate lineages. Our evidence suggests that 11 nonhuman primate species have one RHOXF2 copy, and two copies are present in humans and four Old World monkey species, and at least 6 copies in chimpanzees. Further analysis indicated that the gene duplications in primates had likely been mediated by endogenous retrovirus (ERV) sequences flanking the gene regions. In striking contrast to non-human primates, humans appear to have homogenized their two RHOXF2 copies by the ERV-mediated non-allelic recombination mechanism. Coding sequence and phylogenetic analysis suggested multi-lineage strong positive selection on RHOXF2 during primate evolution, especially during the origins of humans and chimpanzees. All the 8 coding region polymorphic sites in human populations are non-synonymous, implying on-going selection. Gene expression analysis demonstrated that besides the preferential expression in the reproductive system, RHOXF2 is also expressed in the brain. The quantitative data suggests expression pattern divergence among primate species. CONCLUSIONS: RHOXF2 is a fast-evolving homeobox gene in primates. The rapid evolution and copy number changes of RHOXF2 had been driven by Darwinian positive selection acting on the male reproductive system and possibly also on the central nervous system, which sheds light on understanding the role of homeobox genes in adaptive evolution.

Molecular evolution of a primate-specific microRNA family.

Lineage-specific microRNA (miRNA) families may contribute to developmental novelties during evolution. However, little is known about the origin and evolution of new miRNA families. We report evidence of an Alu-mediated rapid expansion of miRNA genes in a previously identified primate-specific miRNA family, drawn from sequencing and comparative analysis of 9 diverse primate species. Evolutionary analysis reveals similar divergence among miRNA copies whether they are within or between species, lineage-specific gain and loss of miRNAs, and gene pseudolization in multiple species. These observations support a birth-and-death process of miRNA genes in this family, implicating functional diversification during primate evolution. In addition, both secondary structure conservation and reduced single nucleotide polymorphisms density attest to functional constraint of this family in primates. Finally, we observed preferential expression of miRNAs in human placenta and fetal brain, suggesting a functional importance of this family for primate development.

Rapid evolution, genetic variations, and functional association of the human spermatogenesis-related gene NYD-SP12.

NYD-SP12 is a recently identified spermatogenesis-related gene with a pivotal role in human testis development. In this study, we analyzed between-species divergence and within-species variation of NYD-SP12 in seven representative primate species, four worldwide human populations, and 124 human clinical subjects. Our results indicate that NYD-SP12 evolves rapidly in both the human and the chimpanzee lineages, which is likely caused by Darwinian positive selection and/or sexual selection. We observed significant interpopulation divergence among human populations, which might be due to the varied demographic histories. In the association analysis, we demonstrated significant frequency discrepancy of a synonymous sequence polymorphism among the clinical groups with different sperm traits.

Adaptive evolution of primate TRIM5alpha, a gene restricting HIV-1 infection.

Recent studies showed that nonhuman primate TRIM5alpha can efficiently block HIV-1 infection in human cell lines. It can also restrict other retroviruses, therefore, suggested as a general defender against retrovirus infection. Here, we present an evolutionary analysis of TRIM5alpha in primates. Our results demonstrated that TRIM5alpha has been evolving rapidly in primates, which is likely caused by Darwinian positive selection. The SPRY domain of TRIM5alpha, which may be responsible for recognition of incoming viral capsids showed higher nonsynonymous/synonymous substitution ratios than the non-SPRY domain, indicating that the adaptive evolution of TRIM5alpha in primates might be an innate strategy developed in defending retrovirus infection during primate evolution. In addition, the comparative protein sequence analysis suggested that the amino acid substitution pattern at a single site (344R/Q/P) located in the SPRY domain may explain the differences in susceptibilities of HIV-1 infection in diverse primate species.

Accelerated evolution of the pituitary adenylate cyclase-activating polypeptide precursor gene during human origin.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide abundantly expressed in the central nervous system and involved in regulating neurogenesis and neuronal signal transduction. The amino acid sequence of PACAP is extremely conserved across vertebrate species, indicating a strong functional constraint during the course of evolution. However, through comparative sequence analysis, we demonstrated that the PACAP precursor gene underwent an accelerated evolution in the human lineage since the divergence from chimpanzees, and the amino acid substitution rate in humans is at least seven times faster than that in other mammal species resulting from strong Darwinian positive selection. Eleven human-specific amino acid changes were identified in the PACAP precursors, which are conserved from murine to African apes. Protein structural analysis suggested that a putative novel neuropeptide might have originated during human evolution and functioned in the human brain. Our data suggested that the PACAP precursor gene underwent adaptive changes during human origin and may have contributed to the formation of human cognition.

Recent origin of a hominoid-specific splice form of neuropsin, a gene involved in learning and memory.

Neuropsin is a secreted-type serine protease involved in learning and memory. The type II splice form of neuropsin is abundantly expressed in the human brain but not in the mouse brain. We sequenced the type II-spliced region of neuropsin gene in humans and representative nonhuman primate species. Our comparative sequence analysis showed that only the hominoid species (humans and apes) have the intact open reading frame of the type II splice form, indicating that the type II neuropsin originated recently in the primate lineage about 18 MYA. Expression analysis using RT-PCR detected abundant expression of the type II form in the frontal lobe of the adult human brain, but no expression was detected in the brains of lesser apes and Old World monkeys, indicating that the type II form of neuropsin only became functional in recent time, and it might contribute to the progressive change of cognitive abilities during primate evolution.

Molecular evolution of microcephalin, a gene determining human brain size.

Microcephalin gene is one of the major players in regulating human brain development. It was reported that truncated mutations in this gene can cause primary microcephaly in humans with a brain size comparable with that of early hominids. We studied the molecular evolution of microcephalin by sequencing the coding region of microcephalin gene in humans and 12 representative non-human primate species covering great apes, lesser apes, Old World monkeys and New World monkeys. Our results showed that microcephalin is highly polymorphic in human populations. We observed 22 substitutions in the coding region of microcephalin gene in human populations, with 15 of them causing amino acid changes. The neutrality tests and phylogenetic analysis indicated that the rich sequence variations of microcephalin in humans are likely caused by the combination of recent population expansion and Darwinian positive selection. The synonymous/non-synonymous analyses in primates revealed positive selection on microcephalin during the origin of the last common ancestor of humans and great apes, which coincides with the drastic brain enlargement from lesser apes to great apes. The codon-based neutrality test also indicated the signal of positive selection on five individual amino acid sites of microcephalin, which may contribute to brain enlargement during primate evolution and human origin.