Two microbes assisting Miscanthus floridulus in remediating multi-metal(loid)s-contaminated soil.

Miscanthus has good tolerance to multi-metal(loid)s and has received increasing attention in remediated studies of metal(loid)s-contaminated soil. In this study, we conducted phytoextraction techniques to investigate the synergic effects of remediation of multi-metal(loid)s-contaminated soil by Miscanthus floridulus (Lab.) and two plant growth-promoting bacteria (PGPB), TS8 and MR2, affiliated to Enterobacteriaceae. The results exhibited a decrease of arsenic (15.27-21.50%), cadmium (8.64-15.52%), plumbum (5.92-12.76%), and zinc (12.84-24.20%) except for copper contents in the soil in bacterial inoculation groups, indicating that MR2 and TS8 could enhance the remediation of metal(loid)s. Moreover, increased fresh/dry weight and height indicated that inoculated bacteria could promote Miscanthus growth. Although the activities of antioxidant enzymes and the content of chlorophyll in the overground tissues showed no significant increase or even decrease, the activities of antioxidant enzymes in the underground tissues and soil were elevated by 48.95-354.17%, available P by 19.07-23.02%, and available K by 15.34-17.79% (p < 0.05). Bacterial inoculants could also decrease the soil pH. High-throughput sequencing analysis showed that the bacterial inoculant affected the rhizosphere bacterial community and reduced community diversity, but the relative abundance of some PGPB was found to increase. Phylogenetic molecular ecological networks indicated that bacterial inoculants reduced interactions between rhizosphere bacteria and thereby led to a simpler network structure but increased the proportion of positive-correlation links and enhanced the metabiosis and symbiosis of those bacteria. Spearman's test showed that OTUs affiliated with Enterobacteriaceae and soil nutrients were critical for metal(loid) remediation and Miscanthus growth. The results of this study provide a basis for the synergic remediation of multi-metal(loid)s-contaminated soils by Miscanthus and PGPB and provide a reference for the subsequent regulation of Miscanthus remediation efficiency by the other PGPB or critical bacteria.

Promotion of rice seedlings growth and enhancement of cadmium immobilization under cadmium stress with two types of organic fertilizer.

Cadmium (Cd)-contaminated soil poses a severe threat to crop production and human health, while also resulting in a waste of land resources. In this study, two types of organic fertilizer (ZCK: Low-content available iron; Z2: High-content available iron) were applied to Cd-contaminated soil for rice cultivation, and the effects of the fertilizer on rice growth and Cd passivation were investigated in conjunction with soil microbial analysis. Results showed that Z2 could alter the composition, structure, and diversity of microbial communities, as well as enhance the complexity and stability of the microbial network. Both 2% and 5% Z2 significantly increased the fresh weight and dry weight of rice plants while suppressing Cd absorption. The 2% Z2 exhibited the best Cd passivation effect. Gene predictions suggested that Z2 may promote plant growth by regulating microbial production of organic acids that dissolve phosphorus and potassium. Furthermore, it is suggested that Z2 may facilitate the absorption and immobilization of soil cadmium through the regulation of microbial cadmium efflux and uptake systems, as well as via the secretion of extracellular polysaccharides. In summary, Z2 can promote rice growth, suppress Cd absorption by rice, and passivate soil Cd by regulating soil microbial communities.

Glycolysis induces Th2 cell infiltration and significantly affects prognosis and immunotherapy response to lung adenocarcinoma.

Glycolysis has a major role in cancer progression and can affect the tumor immune microenvironment, while its specific role in lung adenocarcinoma (LUAD) remains poorly studied. We obtained publicly available data from The Cancer Genome Atlas and Gene Expression Omnibus databases and used R software to analyze the specific role of glycolysis in LUAD. The Single Sample Gene Set Enrichment Analysis (ssGSEA) indicated a correlation between glycolysis and unfavorable clinical outcome, as well as a repression effect on the immunotherapy response of LUAD patients. Pathway enrichment analysis revealed a significant enrichment of MYC targets, epithelial-mesenchymal transition (EMT), hypoxia, G2M checkpoint, and mTORC1 signaling pathways in patients with higher activity of glycolysis. Immune infiltration analysis showed a higher infiltration of M0 and M1 macrophages in patients with elevated activity of glycolysis. Moreover, we developed a prognosis model based on six glycolysis-related genes, including DLGAP5, TOP2A, KIF20A, OIP5, HJURP, and ANLN. Both the training and validation cohorts demonstrated the high efficiency of prognostic prediction in this model, which identified that patients with high risk may have a poorer prognosis and lower sensitivity to immunotherapy. Additionally, we also found that Th2 cell infiltration may predict poorer survival and resistance to immunotherapy. The study indicated that glycolysis is significantly associated with poor prognosis in patients with LUAD and immunotherapy resistance, which might be partly dependent on the Th2 cell infiltration. Additionally, the signature comprised of six genes related to glycolysis showed promising predictive value for LUAD prognosis.

Potential roles of the rhizospheric bacterial community in assisting Miscanthus floridulus in remediating multi-metal(loid)s contaminated soils.

Phytoremediation technology is an important approach applied to heavy metal remediation, and how to improve its remediation efficiency is the key. In this study, we compared the rhizospheric bacterial communities and metals contents in Miscanthus floridulus (M. floridulus) of four towns, including Huayuan Town (HY), Longtan Town (LT), Maoer Village (ME), and Minle Town (ML) around the lead-zinc mining area in Huayuan County, China. The roles of rhizospheric bacterial communities in assisting the phytoremediation of M. floridulus were explored. It was found that the compositions of the rhizospheric bacterial community of M. floridulus differed in four regions, but majority of them were heavy metal-resistant bacteria that could promote plant growth. Results of bioconcentration factors showed the enrichment of Cu, Zn, and Pb by M. floridulus in these four regions were significantly different. The Zn enrichment capacity of ML was the strongest for Cu and stronger than LT and ME for Pb. The enrichment capacity of LT and ML was stronger than HY and ME. These bacteria may influence the different heavy metals uptake of M. floridulus by altering the soil physiochemical properties (e.g., soil peroxidase, pH and moisture content). In addition, co-occurrence network analysis also showed that LT and ML had higher network stability and complexity than HY and ME. Functional prediction analysis of the rhizospheric bacterial community showed that genes related to protein synthesis (e.g., zinc-binding alcohol dehydrogenase/oxidoreductase, Dtx R family transcriptional regulators and ACC deaminase) also contributed to phytoremediation in various ways. This study provides theoretical guidance for selecting suitable microorganisms to assist in the phytoremediation of heavy metals.

Neuronal C-Reactive Protein/FcγRI Positive Feedback Proinflammatory Signaling Contributes to Nerve Injury Induced Neuropathic Pain.

Neuropathic pain is difficult to treat in clinical practice, and the underlying mechanisms are insufficiently elucidated. Previous studies have demonstrated that the neuronal Fc-gamma-receptor type I (FcγRI) of the dorsal root ganglion (DRG) mediates antigen-specific pain. However, the mechanisms of neuronal FcγRI in neuropathic pain remain to be explored. Here, it is found that the activation of FcγRI-related signals in primary neurons induces neuropathic pain in a rat model. This work first reveals that sciatic nerve injury persistently activates neuronal FcγRI-related signaling in the DRG, and conditional knockout (CKO) of the FcγRI-encoding gene Fcgr1 in rat DRG neurons significantly alleviates neuropathic pain after nerve injury. C-reactive protein (CRP) is increased in the DRG after nerve injury, and CRP protein of the DRG evokes pain by activating neuronal FcγRI-related signals. Furthermore, microinjection of naive IgG into the DRG alleviates neuropathic pain by suppressing the activation of neuronal FcγRI. These results indicate that the activation of neuronal CRP/FcγRI-related signaling plays an important role in the development of neuropathic pain in chronic constriction injury (CCI) rats. The findings may provide novel insights into the neuroimmune responses after peripheral nerve injury and suggest potential therapeutic targets for neuropathic pain.

Pristane cadmium chloride nanoemulsion accelerates the onset of systemic lupus erythematosus in a C57BL/6 mouse model.

OBJECTIVE: To accelerate the onset of systemic lupus erythematosus in C57BL/6 mice by injecting cadmium chloride nanoemulsion and shorten the traditional modeling time. METHODS: Pristane cadmium chloride nanoemulsion was prepared, and 66 C57BL/6 mice were randomly divided into four groups. The pristane group was intraperitoneally injected with 0.6 mL of pristane blank nanoemulsion, the model group was injected with 0.6 mL of pristane cadmium chloride nanoemulsion, the Cadmium chloride control group was injected with 0.6 mL of cadmium chloride nanoemulsion, and the control group was injected with the same amount of 0.9% sodium chloride solution. Urine protein content, anti-dsDNA antibody content, Th1 cell/Th2 cell ratio, and kidney staining were detected in each group. RESULTS: The model group began to develop disease in the 4th week, the anti-dsDNA antibody level reached 566.71 ± 1.44 ng/L, and the proteinuria reached 245.38 ± 30.54 ng/mL. The model group showed an onset at least 5 weeks earlier than that in the pristane group. There was no significant difference in anti-dsDNA antibody content between Cadmium chloride control group and blank group. At the 12th week, the Th1/Th2 cell ratio in the model group significantly decreased, and the pathological changes in the kidneys were consistent with the typical manifestations of lupus in mouse models. CONCLUSION: These results suggest that cadmium chloride promotes earlier onset of pristane-induced systemic lupus erythematosus in a C57BL/6 mouse model.

Highly Stretchable and Sensitive Flexible Strain Sensor Based on Fe NWs/Graphene/PEDOT:PSS with a Porous Structure.

With the rapid development of wearable smart electronic products, high-performance wearable flexible strain sensors are urgently needed. In this paper, a flexible strain sensor device with Fe NWs/Graphene/PEDOT:PSS material added under a porous structure was designed and prepared. The effects of adding different sensing materials and a different number of dips with PEDOT:PSS on the device performance were investigated. The experiments show that the flexible strain sensor obtained by using Fe NWs, graphene, and PEDOT:PSS composite is dipped in polyurethane foam once and vacuum dried in turn with a local linearity of 98.8%, and the device was stable up to 3500 times at 80% strain. The high linearity and good stability are based on the three-dimensional network structure of polyurethane foam, combined with the excellent electrical conductivity of Fe NWs, the bridging and passivation effects of graphene, and the stabilization effect of PEDOT:PSS, which force the graphene-coated Fe NWs to adhere to the porous skeleton under the action of PEDOT:PSS to form a stable three-dimensional conductive network. Flexible strain sensor devices can be applied to smart robots and other fields and show broad application prospects in intelligent wearable devices.

TRPC6 inhibits renal tubular epithelial cell pyroptosis through regulating zinc influx and alleviates renal ischemia-reperfusion injury.

Canonical transient receptor potential-6 (TRPC6) has been reported to be involved in cell damage after ischemia/reperfusion (I/R) injury in target organs. While the effect and of TRPC6 on pyroptosis in renal I/R injury remain unclear. In our study, we first established the renal I/R mouse model and oxygen-glucose deprivation and re-oxygenation (OGD/R) cell model, and investigated the impacts of TRPC6 on the pyroptosis-related proteins using CCK-8, western blot, ELISA, and immunofluorescence probes. Besides, we also explored the mechanism of TRPC6 in pyroptosis of renal tubular epithelial cells through A20 knockdown or overexpression and zinc chloride (ZnCl2 ) or a zinc ion chelator (TPEN) treatment. Our results indicated that I/R injury could cause downregulation of TRPC6 both in vivo and in vitro. In the I/R injury murine model, TRPC6 inhibition exacerbated tissue damage and upregulated NLRP3, ASC, caspase-1, IL-18, and IL-1ß, which could be alleviated by the administration of ZnCl2 . In the OGD/R cell model, inhibitor of TRPC6 (SAR7334) reduced zinc ion influx, aggravated cell death and upregulated pyroptosis-related protein. The pyroptosis phenotype also could be alleviated by ZnCl2 and intensified by TPEN. Overexpression of A20 reduced the expression of pyroptosis-related protein, increased cell viability in the sh-TRPC6 and TPEN-treated OGD/R cell models, while A20 deficiency impaired the protective effect of zinc ion. Therefore, our results indicate that TRPC6 could promote zinc ion influx in renal tubular epithelial cells, thereby upregulating intracellular A20, inhibiting the activation of inflammasome NLRP3, and ultimately attenuating renal I/R injury.

Phosphorylation-dependent positive feedback on the oxytocin receptor through the kinase PKD1 contributes to long-term social memory.

Social memory enables one to recognize and distinguish specific individuals. It is fundamental to social behaviors that can be mediated by the oxytocin receptor (OXTR), such as forming relationships. We investigated the molecular regulation and function of OXTR in animal behavior involving social memory. We found that Ser261 in OXTR was phosphorylated by protein kinase D1 (PKD1). Neuronal Ca2+ signaling and behavior analyses revealed that rats expressing a mutated form of OXTR that cannot be phosphorylated at this residue (OXTR S261A) in the medial amygdala (MeA) exhibited impaired long-term social memory (LTSM). Blocking the phosphorylation of wild-type OXTR in the MeA using an interfering peptide in rats or through conditional knockout of Pkd1 in mice reduced social memory retention, whereas expression of a phosphomimetic mutant of OXTR rescued it. In HEK293A cells, the PKD1-mediated phosphorylation of OXTR promoted its binding to Gq protein and, in turn, OXTR-mediated phosphorylation of PKD1, indicating a positive feedback loop. In addition, OXTR with a single-nucleotide polymorphism found in humans (rs200362197), which has a mutation in the conserved recognition region in the PKD1 phosphorylation site, showed impaired activation and signaling in vitro and in HEK293A cells similar to that of the S216A mutant. Our findings describe a phosphoregulatory loop for OXTR and its critical role in social behavior that might be further explored in associated disorders.

Effects of Cold-Pressing and Hydrodistillation on the Active Non-volatile Components in Lemon Essential Oil and the Effects of the Resulting Oils on Aging-Related Oxidative Stress in Mice.

The aim of this study was to analyze the non-volatile composition and antioxidant differences of lemon essential oils (LEOs) obtained by cold-pressing vs. hydrodistillation. Pathological observations showed that LEO effectively inhibited liver injury caused by oxidative stress, and CPLEO was more effective than HDLEO. CPLEO increased serum T-AOC, SOD, GSH, and GSH-Px levels while decreasing NO, COX-2, IL-6, IL-1ß, IFN-γ, and TNF-α levels in mice with oxidative damage. The effects of CPLEO were stronger than those of HDLEO and similar to those of vitamin C. CPLEO upregulated mRNA and protein expressions of Cu/Zn-SOD, Mn-SOD, CAT, HO-1, Nrf2, and NQO1 while downregulating nNOS, iNOS, IL-1ß, COX-2, TNF-α, and NF-κB mRNA expression and nNOS, eNOS, iNOS, and COX-2 protein expression in mice with oxidative damage. The results demonstrate that LEO has good antioxidant effects and that CPLEO has a better antioxidant effect than HDLEO as it retains more active non-volatile substances.

mascRNA and its parent lncRNA MALAT1 promote proliferation and metastasis of hepatocellular carcinoma cells by activating ERK/MAPK signaling pathway.

MALAT1-associated small cytoplasmic RNA (mascRNA) is a cytoplasmic tRNA-like small RNA derived from nucleus-located long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1). While MALAT1 was extensively studied and was found to function in multiple cellular processes, including tumorigenesis and tumor progression, the role of mascRNA was largely unknown. Here we show that mascRNA is upregulated in multiple cancer cell lines and hepatocellular carcinoma (HCC) clinical samples. Using HCC cells as model, we found that mascRNA and its parent lncRNA MALAT1 can both promote cell proliferation, migration, and invasion in vitro. Correspondingly, both of them can enhance the tumor growth in mice subcutaneous tumor model and can promote metastasis by tail intravenous injection of HCC cells. Furthermore, we revealed that mascRNA and MALAT1 can both activate ERK/MAPK signaling pathway, which regulates metastasis-related genes and may contribute to the aggressive phenotype of HCC cells. Our results indicate a coordination in function and mechanism of mascRNA and MALAT1 during development and progress of HCC, and provide a paradigm for deciphering tRNA-like structures and their parent transcripts in mammalian cells.

Epidemic prevention and control measures in China significantly curbed the epidemic of COVID-19 and influenza

At the end of 2019, an outbreak of unknown pathogen pneumonia occurred in China, then it was named corona virus disease 2019 (COVID-19). With the rapid spread of COVID-19, a series of strict prevention and control measures were implemented to cut the spread of the epidemic. Influenza as a respiratory tract infection disease as COVID-19 might also be controlled. To assess the effects, we used the total passenger numbers sent in mainland China from 2018 to 2020 and the daily number of railway passenger (DNRP) flow in 2020 during Spring Festival travel rush to reflect the population movement and further to analyze newly and cumulative confirmed COVID-19 and influenza. We found that with implementing the series measures on COVID-19, not only COVID-19, but also influenza mitigated in China. The prevention and control measures for COVID-19 might be used in controlling respiratory tract diseases, and reducing the national health economic burden. When other countries issue measures on COVID-19 and influenza, they should consider adopting more aggressive epidemic prevention and control strategies.

Failure of Placebo Analgesia Model in Rats with Inflammatory Pain.

With the shifting role of placebos, there is a need to develop animal models of placebo analgesia and elucidate the mechanisms underlying the effect. In the present study, male Sprague-Dawley rats with chronic inflammatory pain caused by complete Freund's adjuvant (CFA) underwent a series of conditioning procedures, in which morphine was associated with different cues, but they failed to induce placebo analgesia. Then, conditioning with the conditioned place preference apparatus successfully induced analgesic expectancy and placebo analgesia in naïve rats but only induced analgesic expectancy and no analgesic effect in CFA rats. Subsequently, we found enhanced c-fos expression in the nucleus accumbens and reduced expression in the anterior cingulate cortex in naïve rats while c-fos expression in the anterior cingulate cortex in CFA rats was not altered. In summary, the behavioral conditioning model demonstrated the difficulty of establishing a placebo analgesia model in rats with a pathological condition.

Occult HBV infection in patients with autoimmune hepatitis: A virological and clinical study.

BACKGROUND/PURPOSE: Occult HBV infection (OBI) could have serious clinical consequences in patients receiving immunosuppressive therapy. We aimed to investigate the prevalence of OBI in Chinese patients with autoimmune hepatitis (AIH) and to analyze its clinical and virological features. METHODS: 103 AIH cases were enrolled. Hepatitis B virus (HBV) serological markers were screened by chemiluminescence. HBV-DNA were detected by nest-PCR and real-time PCR. HBV genotyping and mutation analysis were performed by Sanger sequencing. RESULTS: Twenty-four out of 103 (23.30%) AIH patients had OBI as evidenced by positive HBV-DNA and negative hepatitis B surface antigen (HBsAg). HBV genotype C is the predominant genotype (57.89%), which had more amino acid (AA) substitutions in S region than that of B-genotype group (P = 0.001). The distribution of AA substitution in the 'α' determinant region between genotype C and B were significantly different (P = 0.042). In addition to those already reported OBI-associated AA substitutions (e.g., sG145R and sV184A), some new OBI-associated AA substitutions (e.g., sV106A, sC137* and sL176P) were found in AIH patients in our study. Three out of 24 (12.50%) OBI patients were diagnosed as decompensated cirrhosis, one patient with S deletion mutation and two patients with HBV extensive AA substitutions. CONCLUSIONS: There was a higher proportion of AIH patients with OBI than the general population in China, which can be either seropositive or seronegative-OBI in AIH patients is associated with some specific AA substitutions. The presence of deletion mutations and the extent of AA substitutions in the HBV S region may have predictive clinical implications.

Direct antiviral agents upregulate natural killer cell potential activity in chronic hepatitis C patients.

Direct antiviral agents (DAAs) can eliminate hepatitis C virus rapidly and make chronic hepatitis C (CHC) curable. The changes in the innate immune system during treatment with DAAs are still in dispute. To investigate how the functions of natural killer (NK) cells change during and after treatment with DAAs in each NK cell subset. Thirteen CHC patients were treated with sofosbuvir/ledipasvir, and the expression levels of NKp46 and NKG2A were tested via flow cytometry at baseline, at 2, 4, 8 and 12 weeks during the therapy and 12 and 24 weeks after the end of treatment; expression levels were compared between CHC patients and 13 healthy controls. A redirected killing assay was used to detect the cytotoxicity of NK cells. After coculturing NK cells with JFH-Huh7 cells for 72 h, HCV RNA was tested to analyze the inhibition ability of NK cells. All patients achieved sustained virologic response. The expression of the activating receptor NKp46 was decreased first at week 8 during therapy with DAAs and then increased and normalized to levels in healthy controls after treatment with DAAs. The expression of the inhibitory receptor NKG2A was decreased during and after treatment with DAAs. Each NK cell subset has a similar changing trend during and after treatment with DAAs, although some differences can be found earlier and later. The ratio of NKp46 and NKG2A was upregulated after treatment with DAAs. CD56bright NK cells have less amplitude in the frequency ratio changes after treatment with DAAs. The coculture results showed that both the specific lysis and the inhibition of HCV replication were significantly upregulated after treatment with DAAs. DAA treatments can affect patients' NK cell function. After DAA treatments, the expression of functional markers is downregulated, but the potential activity of NK cells is upregulated. The function of NK cells is normalized to levels in healthy controls. CD56bright NK cells play an important role in this process.

Atomically Tailored Gold Nanoclusters for Catalytic Application.

Recent advances in the synthetic chemistry of atomically precise metal nanoclusters (NCs) have significantly broadened the accessible sizes and structures. Such particles are well defined and have intriguing properties, thus, they are attractive for catalysis. Especially, those NCs with identical size but different core (or surface) structure provide unique opportunities that allow the specific role of the core and the surface to be mapped out without complication by the size effect. Herein, we summarize recent work with isomeric Aun NCs protected by ligands and isostructural NCs but with different surface ligands. The highlighted work includes catalysis by spherical and rod-shaped Au25 (with different ligands), quasi-isomeric Au28 (SR)20 with different R groups, structural isomers of Au38 (SR)24 (with identical R) and Au38 S2 (SR)20 with body-centred cubic (bcc) structure, and isostructural [Au38 L20 (PPh3 )4 ]2+ (different L). These isomeric and/or isostructural NCs have provided valuable insights into the respective roles of the kernel, surface staples, and the type of ligands on catalysis. Future studies will lead to fundamental advances and development of tailor-made catalysts.

Layer-sliding-driven crystal size and photoluminescence change in a novel SCC-MOF.

A novel silver-chalcogenolate cluster-based framework Ag12TPPA·AA with long-lived afterglow was successfully synthesized. It transformed into more densely packed Ag12TPPA·AB and Ag12TPPA·ABC by layer sliding accompanied by macroscopic crystal contraction and changing luminescence.

Tandem Silver Cluster Isomerism and Mixed Linkers to Modulate the Photoluminescence of Cluster-Assembled Materials.

Silver chalcogenolate cluster assembled materials (SCAMs) are a category of promising light-emitting materials the luminescence of which can be modulated by variation of their building blocks (cluster nodes and organic linkers). The transformation of a singly emissive [Ag12 (SBut )8 (CF3 COO)4 (bpy)4 ]n (Ag12 bpy, bpy=4,4'-bipyridine) into a dual-emissive [(Ag12 (SBut )6 (CF3 COO)6 (bpy)3 )]n (Ag12 bpy-2) via cluster-node isomerization, the critical importance of which was highlighted in dictating the photoluminescence properties of SCAMs. Moreover, the newly obtained Ag12 bpy-2 served to construct visual thermochromic Ag12 bpy-2/NH2 by a mixed-linker synthesis, together with dichromatic core-shell Ag12 bpy-2@Ag12 bpy-NH2 -2 via solvent-assisted linker exchange. This work provides insight into the significance of metal arrangement on physical properties of nanoclusters.

Self-Assembly of a Stable Silver Thiolate Nanocluster Encapsulating a Lacunary Keggin Phosphotungstate Anion.

A polyoxometalate-templated silver(I) thiolate nanocluster has been synthesized by a one-pot reaction in high yield. This novel and stable nanocluster exhibits a core-shell structure with a Ag67S36 shell and two lacunary Keggin [PW9O34]9- cores, which is fully characterized by X-ray crystallography, X-ray photoelectron spectroscopy, UV-vis, powder X-ray diffraction, and cyclic voltammetry.

HBsAg stimulates NKG2D receptor expression on natural killer cells and inhibits hepatitis C virus replication.

BACKGROUND: Higher hepatitis B surface antigen (HBsAg) facilitates hepatitis C virus (HCV) clearance in patients with hepatitis B virus (HBV)/HCV co-infection. We investigated the effect of exogenous HBsAg on the inhibition of HCV replication mediated by natural killer (NK) cells. METHODS: After isolated from peripheral blood of 42 chronic hepatitis B (CHB) patients and 16 healthy individuals, NK cells were co-cultured with HCV-infected Huh7 cells, respectively, with or without HBsAg. Three days later, the co-cultured supernatants were collected and HCV RNA levels were measured by real-time quantitative PCR. NKG2D, NKp46 and NKG2A expression levels were measured by flow cytometry. NKG2D on NK cells from CHB responsive subgroup was blocked and HCV RNA levels were examined again. RESULTS: HCV RNA levels in the co-cultured system were significantly reduced by NK cells isolated from healthy donors (P < 0.01) but not from CHB patients. However, HCV RNA levels in CHB cultures were significantly decreased following HBsAg addition (P < 0.05), whereas no such effect was seen in control cultures. No significant difference was observed in basic NKG2D expression between the CHB patients and healthy donors. On NK cells from CHB patients, the expression of NKG2D was increased significantly by HBsAg stimulation (P < 0.01), and higher than that from healthy controls (P < 0.05). HCV RNA levels were increased significantly after the blockage of NKG2D on NK cells from responsive CHB patients in the co-cultured system (P < 0.05). CONCLUSION: Exogenous HBsAg stimulated NKG2D expression on NK cells from CHB patients which inhibit HCV replication, suggesting that HBsAg may facilitate the clearance of HCV in patients with HBV/HCV co-infection.