Inositol hexaphosphate-induced enhancement of natural killer cell activity correlates with suppression of colon carcinogenesis in rats

AIM： To investigate the anti-neoplastic effect of inositol hexaphosphate （InsP6 or phytic acid） on dimethylhydrazine （DMH）-induced colon tumor in rats and its effect on blood natural killer （NK） cell activity. METHODS： Healthy Wistar rats, 4 wk old, were divided into control group （fed with common food） and InsP6 group （fed with common food＋2% sodium inositol hexaphosphate in the drinking water）, 15 rats in each group. Both groups were injected with 1,2-dimethylhydrazine subcutaneously （20 mg/kg body weight） once a week for 20 wk. Rats were killed after 21 wk. The whole large intestine was isolated to determine the general condition of tumors and to test blood NK cell activity by lactate-dehydrogenase-release assay. RESULTS： Administration of InsP6 significantly increased blood NK cell activity in DMH-induced colorectal tumor in rats. InsP6 group had a smaller tumor size on average and a smaller number of tumors than the control group. Its mortality was also higher than that in control. However, the variables of body weight and tumor incidence were not significantly different between the two groups. CONCLUSION： InsP6 can increase blood NK cell activity in DMH-induced colon tumor in rats and inhibit tumor growth and metastasis in rats.

REGULATORY EFFECTS OF HUMAN RECOMBINANT IL-6 ON NATURAL KILLER CELL ACTIVITY OF HUMAN FETAL SPLEENS

In the present study it was proved first that human recombinant interleukin-6(HrIL-6) significantly augmented natural killer(NK) cell activity derived from human fetal spleens against K562 target cells in a 4 hours 51Cr release assay. The enhancement of NK activity with 24 hours preincubation in HrlL-6 was dose-dependent, and significantly higher than that of fresh NK cells and controls cultured with RPMI-1640 medium alone (P<0.001). We also found that IL-6 was able to augment NK activity from different fetal spleens at 20 to 40 weeks of gestation (up to 2.24 to 2.78 times), and no difference of NK activity of fetal splenocytes treated by HrIL-6 was observed between different fetal age (32.3% to 45.4%, P>0.05). Furthermore, IL-6-augmented NK activity of fetal splenocytes was very similar to adult levels (P>0.05). These finding strongly indicated that IL-6 plays an important role in the development of NK cell function during the gestational period, suggesting that IL-6 may be of importance in the regulation of host defense mechanisms against malignancies and viral diseases.

Pharmacological Investigation on the Qi-Invigorating Action of Schisandrin B: Effects on Mitochondrial ATP Generation in Multiple Tissues and Innate/Adaptive Immunity in Mice

Schisandrae Fructus, containing schisandrin B (Sch B) as its main active component, is recognized in traditional Chinese medicine (TCM) for its Qi-invigorating properties in the five visceral organs. Our laboratory has shown that the Qi-invigorating action of Chinese tonifying herbs is linked to increased mitochondrial ATP generation and an enhancement in mitochondrial glutathione redox status. To explore whether Sch B can exert Qi-invigorating actions across various tissues, we investigated the effects of Sch B treatment on mitochondrial ATP generation and glutathione redox status in multiple mouse tissues ex vivo. In line with TCM theory, which posits that Zheng Qi generation relies on the Qi function of the visceral organs, we also examined Sch B’s impact on natural killer cell activity and antigen-induced splenocyte proliferation, both serving as indirect measures of Zheng Qi. Our findings revealed that Sch B treatment consistently enhanced mitochondrial ATP generation and improved mitochondrial glutathione redox status in mouse tissues. This boost in mitochondrial function was associated with stimulated innate and adaptive immune responses, marked by increased natural killer cell activity and antigen-induced T/B cell proliferation, potentially through the increased generation of Zheng Qi.

Differential Effects of Yin- and Yang-Chinese Tonifying Herbs on Innate and Adaptive Immunity

The present study investigated the effect of treatment with methanolic extracts of Yin- and Yang-Chinese tonifying herbs on concanavalin A (Con A)/lipopolysaccharide (LPS)-stimulated splenocyte proliferation (adaptive immunity) and natural killer (NK) cell activity (innate immunity) in an ex vivo mouse model. The results indicated that while treatment with most Yin herbal extracts potentiated the Con A/LPS-stimulated splenocyte proliferation, only Yang (but not Yin) herbal extracts stimulated NK cell activity. The differential effects of Yin- and Yang-Chinese tonifying herbs on innate and adaptive immunity are consistent with the Chinese medicine theory which depicts the Yin and Yang functional components of Zheng Qi (vital energy), with the Yang component being responsible for the first line of defense against invading microorganisms (i.e., innate immunity) and the Yin oner serving as a follow-up defensive response (adaptive immunity).

Impairment of innate immune responses in cirrhotic patients and treatment by branched-chain amino acids

It has been reported that host defense responses, such as phagocytic function of neutrophils and natural killer (NK) cell activity of lymphocytes, are impaired in cirrhotic patients. This review will concentrate on the impairment of innate immune responses in decompensated cirrhotic patients and the effect of the treatment by branched-chain amino acids (BCAA) on innate immune responses. We already reported that phagocytic function of neutrophils was significantly improved by 3-mo BCAA supplementation. In addition, the changes of NK activity were also significant at 3 mo of supplementation compared with before supplementation. Also, Fisher&#x02019;s ratios were reported to be significantly increased at 3 mo of BCAA supplementation compared with those before oral supplementation. Therefore, administration of BCAA could reduce the risk of bacterial and viral infection in patients with decompensated cirrhosis by restoring impaired innate immune responses of the host. In addition, it was also revealed that BCAA oral supplementation could reduce the risk of development of hepatocellular carcinoma in cirrhotic patients. The mechanisms of the effects will also be discussed in this review article.

Attenuated retinoic acid signaling is among the early responses in mouse uterus approaching embryo attachment

The uterus is transiently receptive for embryo implantation.It remains to be understood why the uterus does not reject a semi-allogeneic embryo(to the biological mother)or an allogeneic embryo(to a surrogate)for implantation.To gain insights,we examined uterine early response genes approaching embryo attachment on day 3 post coitum(D3)at 22 hours when blue dye reaction,an indication of embryo attachment,had not manifested in mice.C57BL/6 pseudo-pregnant(control)and pregnant mouse uteri were collected on D3 at 22 hours for microarray analysis.The self-assembling-manifold(SAM)algorithm identified 21,858 unique probesets.Principal component analysis indicated a clear separation between the pseudo-pregnant and pregnant groups.There were 106 upregulated and five downregulated protein-coding genes in the pregnant uterus with fold change(fc)>1.5 andq value<5%.Gene ontology(GO)analysis of the 106 upregulated genes revealed 38 significant GO biological process(GOBP)terms(P<0.05),and 32(84%)of them were associated with immune responses,with a dominant natural killer(NK)cell activation signature.Among the top eight upregulated protein-coding genes,Cyp26a1 inactivates retinoic acid(RA)whileLrat promotes vitamin A storage,both of which are expected to attenuate RA bioavailability;Atp6v0d2 andGjb2 play roles in ion transport and transmembrane transport;Gzmb,Gzmc,andIl2rb are involved in immune responses;andTdo2 is important for kynurenine pathway.Most of these genes or their related pathways have functions in immune regulations.RA signaling has been implicated in immune tolerance and immune homeostasis,and uterine NK cells have been implicated in immunotolerance at the maternal-fetal interface in the placenta.The mechanisms of immune responses approaching embryo attachment remain to be elucidated.The coordinated effects of the early response genes may hold the keys to the question of why the uterus does not reject an implanting embryo.

The Effects of Astragalus membranaceus and Tripterygium hypoglaucum on NK Activity in Systemic Lupus Erythematosus

The natural killer cell activity of peripheral blood mononuclear cells from 28 patients withsystemic lupus erythematosus was measured using enzyme-release assay. The patients exhibited obvi-ously decreased natural killer cell activity compared with the healthy subjects in the control group. Thenatural killer cell dysfonction was related to steroidal therapy, but not to three auto-antibodies. The re-lease of a soluble natural killer cytotoxic factor by the peripheral blood mononuclear cells was tested bycytotoxicity assay induced in K256 cells. This release was significantly lower in the test group than in thecontrol group. Pre-incubation of peripheral blood mononuclear cells with Astragalus membranaceus andTripterygium hypoglaucum considerably enhanced natural killer cytotoxicity by stimulating the release ofsoluble cytotoxic factors.