RIG-I: a multifunctional protein beyond a pattern recognition receptor

It was widely known that retinoic acid inducible gene I (RIG-I) functions as a cytosolic pattern recognition receptor that initiates innate antiviral immunity by detecting exogenous viral RNAs. However, recent studies showed that RIG-I participates in other various cellular activities by sensing endogenous RNAs under different circumstances. For example, RIG-I facilitates the therapy resistance and expansion of breast cancer cells and promotes T cell-independent B cell activation through interferon signaling activation by recognizing non-coding RNAs and endogenous retroviruses in certain situations. While in hepatocellular carcinoma and acute myeloid leukemia, RIG-I acts as a tumor suppressor through either augmenting STAT1 activation by competitively binding STAT1 against its negative regulator SHP1 or inhibiting AKT-mTOR signaling pathway by directly interacting with Src respectively. These new findings suggest that RIG-I plays more diverse roles in various cellular life activities, such as cell proliferation and differentiation, than previously known. Taken together, the function of RIG-I exceeds far beyond that of a pattern recognition receptor.

Effect of nerve growth factor-gelatin sponge composite on peri-implant osseointegration / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To observe the peri-implant osseointegration after the application of exogenous nerve growth factor (NGF)-gelatin sponge (GS) composite.</p><p><b>METHODS</b>Six beagle dogs were used to establish bi-mandible simultaneous implant model after the first and second premolar extraction. Then the dental implants were implanted into the distal socket while the bone defect was made in the mesial socket of each mandible. Then the NGF-GS was implanted into the defects as NGF-GS group, the gelatin sponge alone was implanted as GS control and the control group was left empty. Two dogs were sacrificed each time at 4 weeks, 8 weeks and 12 weeks postoperatively. Specimens were subjected to general observation, radiography, bone histological and histomorphometric analysis for the new bone formation. The data were analyzed with SPSS 11.5 software package.</p><p><b>RESULTS</b>The bone density in the defects around implants at 4 and 8 weeks postoperatively was lower than the normal bone. The bone-implant contact ratio in the NGF-GS group [(57.7 ± 6.4)%] was significantly higher than that in the GS control group and the control group [the ratio were (44.2 ± 3.3)% and (31.2 ± 3.1)%] (P < 0.01) at 4 weeks postoperatively, the bone-implant contact ratio in the GS control group was also significantly higher than that in the control group (P < 0.01) at that time. The bone-implant contact ratio in the NGF-GS group [(94.8 ± 7.7)%] was slightly higher than that in the GS control group and the control group [the ratio were (83.0 ± 4.1)% and (86.4 ± 6.3)%] at 8 weeks postoperatively, but there was no statistical difference (P > 0.05). The bone density in the defects around implants at 12 weeks was almost the same as the normal bone, there was no difference of the bone-implant contact ratio.</p><p><b>CONCLUSIONS</b>NGF-GS application could increase new bone formation, accelerate maturation of trabecular bone around the implants and shorten the period of osseointegration.</p>

Effect of experimental occlusal hypofunction on the three-dimensional microarchitecture of mandibular bone in rats / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of experimental occlusal hypofunction on the architecture of rat's mandibular bone.</p><p><b>METHODS</b>Forty Sprague-Dawley (SD) male rats were randomly divided into experimental occlusal hypofunction group and control group, with 20 rats in each group. Experimental occlusal hypofunction group rats were fitted with a metal cap to the maxillary and mandibular incisor, to eliminate the occlusal forces on rat molars. In control group, a metal ring was fitted to the maxillary and mandibular incisor to maintain molar occlusal contact. Then the rats were killed under deep anaesthesia at 0 week and at the end of 2, 4, 6, and 8 weeks, and the mandibles were immediately removed for measurement of the three-dimensional architecture of cancellous bone in the alveolar process with micro-CT.</p><p><b>RESULTS</b>At the end of week 4, the bone volume/total volume (BV/TV) in the hypofunction group decreased compared with the control group [control group:(0.65 ± 0.05)%, experimental group: (0.60 ± 0.05)%, P < 0.05] and lasted until the end of the experiment [control group: (0.72 ± 0.06)%, experimental group: (0.51 ± 0.07)%, P < 0.01]. The similar result was also observed in trabecula thickness (Tb. Th) in experimental animals [control group: (168 ± 15), (170 ± 25), (180 ± 18) µm, experimental group: (152 ± 20), (145 ± 19), (142 ± 15) µm, P < 0.05]. The trabecula spacing (Tb. Sp) in the hypofunction group increased from the end of week 4 to the end of week 8 compared with the matched control groups [control group: (264 ± 21), (284 ± 17), (282 ± 26) µm, experimental group: (306 ± 30), (316 ± 18), (332 ± 18) µm, P < 0.05]. The trabecula number (Tb.N) of experimental animals decreased from the end of week 6[control group:(3.59 ± 0.22) mm(-1), experimental group: (3.03 ± 0.31) mm(-1), P < 0.05] to the end of week 8[control group: (3.66 ± 0.24) mm(-1), experimental group: (2.85 ± 0.18) mm(-1), P < 0.01].</p><p><b>CONCLUSIONS</b>Experimental occlusal hypofunction can result in the change of mandibular alveolar process three-dimensional architecture.</p>

Multiple organ dysfunction syndrome associated with Mycoplasma pneumoniae infection

In this study, we report one case of a three-year-old boy infected with Mycoplasma pneumonia (MP) and presenting concomitant multiple organ damage of the heart, kidney, lung and liver, among others, together with a brief review for the diagnosis and treatment of MP infection with multiple organ dysfunction syndrome (MODS).

Differentiation of adult mouse mesenchymal stem cells into hepatocytes cultured in a conditioned culture medium of injured hepatocytes / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To establish a method through which murine bone marrow mesenchymal stem cells (MSCs) can be induced into hepatocytes in vitro.</p><p><b>METHODS</b>A conditioned medium of injured hepatocytes (with CCl4 in vivo) was used to culture the isolated MSCs. The differentiated cells were identified by morphological observation, reverse transcription polymerase chain reaction (RT-PCR), immunofluorescence assay (for AFP, Albumin, and CK18) and periodic acid schiff reaction (PAS) for glycogen.</p><p><b>RESULTS</b>The differentiated cells showed characteristics of hepatocytes. PT-PCR detected AFP mRNA on day 5 and it increased gradually until day 15, and then decreased; CK18 mRNA was detected on day 10; TAT was detected on day 20. Immunofluorescence assay for AFP, albumin and CK18 showed positive staining reactions on day 20. PAS positive glycogen granules appeared in the cytoplasm of the differentiated cells.</p><p><b>CONCLUSION</b>MSCs of adult mice cultured in a conditioned medium of injured hepatocytes can differentiate into hepatocytes. This method can be used in further studying of the mechanism of transdifferentiation of MSCs into hepatocytes.</p>

Advances in the research of differentiation of embryonic stem cells into hepatocytes / 生物工程学报

Orthotopic liver transplantation has proven to be effective in the treatment of a variety of life-threatening liver diseases, however, the limitations of donated organs available and long-term immunosuppression provided an impetus for developing alternative therapies. Cell replacement strategies have been one major effective approach for overcoming the obstacles of organ transplantation in recent years. The exogenous cells should be able to proliferate and differentiate into mature hepatic cells after grafting. Use of mature hepatocytes is also hampered by limited tissue source and inability to proliferate and maintain the function for a long term in vitro. Embryonic stem cells are immortal and pluripotent and may provide a novel cell source for potential cell therapy. This review summarizes the mechanisms of controlling early liver development and hepatic differentiation of visceral endoderm in embryoid bodies, and provides an overview of diverse differentiation systems in vitro and in vivo that were applied to hepatic research in recent years. Several studies have demonstrated that ES cell-derived hepatocytes can incorporate into liver tissue and function in vivo , but a few of them have shown complete restoration of liver function after transplantation into mice with liver diseases. Further studies should be made to exploit efficient methods and clinical applications of hepatocytes derived from ES cells in the future. In addition to clinical transplantation for treatment of liver diseases, ES cells can provide a valuable tool for drug discovery applications and study on of molecular basis of hepatic differentiation.