A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Restorative and synergistic efficacy of Kalpaamruthaa, a modified Siddha preparation, on an altered antioxidant status in adjuvant induced arthritic rat model

BACKGROUND: Rheumatoid arthritis (RA) is a prevalent and debilitating disease that affects the joints. Infiltration of blood-derived cells in the affected joints upon activation generate reactive oxygen/nitrogen species, resulting in an oxidative stress. One approach to counteract this oxidative stress is the use of antioxidants as therapeutic agents. OBJECTIVES: Kalpaamruthaa (KA), a modified indigenous Siddha preparation constituting Semecarpus anacardium nut milk extract (SA), Emblica officinalis (EO) and honey was evaluated for its synergistic antioxidant potential in adjuvant induced arthritic rats than sole SA treatment. MATERIALS AND METHODS: Levels/activities of reactive oxygen species (ROS)/reactive nitrogen species (RNS), myeloperoxidase, lipid peroxide and enzymic and non-enzymic antioxidants were determined in control, arthritis induced, SA and KA treated (150 mg/kg b.wt.) animals. RESULTS AND CONCLUSION: The levels/activities of ROS/RNS, myeloperoxidase and lipid peroxide were increased significantly (p<0.05) and the activities of enzymic and non-enzymic antioxidants were in turn decreased in arthritic rats, whereas these changes were reverted to near normal levels upon SA and KA treatment. KA showed an enhanced antioxidant potential than sole treatment of SA in adjuvant induced arthritic rats. KA via enhancing the antioxidant status in adjuvant induced arthritic rats than sole SA treatment proves to be an important therapeutic modality in the management of RA and thereby instituting the role of oxidative stress in the clinical manifestation of the disease RA. The profound antioxidant efficacy of KA than SA alone might be due to the synergistic action of the polyphenols such as flavonoids, tannins and other compounds such as vitamin C and hydroxycinnamates present in KA.     

Hypoxia and its downstream targets in DMBA induced mammary carcinoma: protective role of Semecarpus anacardium nut extract

Tumors are usually exposed to a hypoxic microenvironment due to their irregular growth and abnormal vascular supply. Under hypoxia, gene regulation (selective activation and inactivation of genes) plays an important role in maintenance of tumor. Multiple hypoxic and angiogenic growth factors are expressed for tumor cell survival. In search of novel anticancer drug, Semecarpus anacardium nut extract (SA) was tried against breast cancer. Mammary carcinoma was induced in vivo by 7,12-dimethyl benz(a) anthracene (DMBA) (25mg/kg b.w., p.o.). Tumor development and vascular structures were accelerated by DMBA. Hypoxia inducible factor-1 alpha (HIF-1) was coexpressed with its downstream genes in mammary tissue. Cancer rats were then treated with S. anacardium nut extract (SA) (250mg/kg b.w., p.o.). Delay in the tumor growth was paralleled with a drastic reduction in vascularization by SA treatment. Activities of glycolytic enzymes were normalized with decreased expression of glucose transporter-1 and carbonic anhydrase IX by drug treatment. Inhibition of HIF-1, vascular endothelial growth factor and inducible nitric oxide synthase by SA may in part explain its antiangiogenic action. SA also inhibits endothelial cell proliferation by blocking the overexpressed survival cytokines. In conclusion, our study demonstrates that at least some part of the antitumor activity of SA is due to the suppression of hypoxic and angiogenic factors. The mechanism of this inhibition seems to be through an action of SA on expression of HIF-1 and its downstream targets.     

Purification and characterization of an extracellular polygalacturonase from the thermophilic fungus,Thermomyces lanuginosus

A polygalacturonase was purified from the thermophilic fungus, Thermomyces lanuginosus to apparent homogeneity by ultrafiltration, acetone precipitation and ion-exchange chromatography. The enzyme was maximally active at pH 5.5 and 60 °C. The apparent K_M with potassium pectate was 0.67 mg/ml and the V_max was 7.2 × 10⁵ mol/min/mg protein. The apparent molecular weight of the enzyme was 59 kDa and it contained approximately 10% carbohydrate. The enzyme was completely stable at room temperature (32 ± 3 °C) and retained about 50% activity at 50 °C for 6 h. The zymogram of the purified enzyme revealed two activity bands, one of which was a major one. Polyclonal antibodies raised against the enzyme did not show any immunological relatedness with other mesophilic polygalacturonases.     

Pollen tube growth and guidance is regulated by POP2, an Arabidopsis gene that controls GABA levels

During angiosperm reproduction, pollen grains form a tube that navigates through female tissues to the micropyle, delivering sperm to the egg; the signals that mediate this process are poorly understood. Here, we describe a role for gamma-amino butyric acid (GABA) in pollen tube growth and guidance. In vitro, GABA stimulates pollen tube growth, although vast excesses are inhibitory. The Arabidopsis POP2 gene encodes a transaminase that degrades GABA and contributes to the formation of a gradient leading up to the micropyle. pop2 flowers accumulate GABA, and the growth of many pop2 pollen tubes is arrested, consistent with their in vitro GABA hypersensitivity. Some pop2 tubes continue to grow toward ovules, yet they are misguided, presumably because they target ectopic GABA on the ovule surface. Interestingly, wild-type tubes exhibit normal growth and guidance in pop2 pistils, perhaps by degrading excess GABA and sharpening the gradient leading to the micropyle.     

Loss of LORELEI function in the pistil delays initiation but does not affect embryo development in Arabidopsis thaliana

Double fertilization, uniquely observed in plants, requires successful sperm cell delivery by the pollen tube to the female gametophyte, followed by migration, recognition and fusion of the two sperm cells with two female gametic cells. The female gametophyte not only regulates these steps but also controls the subsequent initiation of seed development. Previously, we reported that loss of LORELEI, which encodes a putative glycosylphosphatidylinositol (GPI)-anchored protein, in the female reproductive tissues causes a delay in initiation of seed development. From these studies, however, it was unclear if embryos derived from fertilization of lre-5 gametophytes continued to lag behind wild-type during seed development. Additionally, it was not determined if the delay in initiation of seed development had any lingering effects during seed germination. Finally, it was not known if loss of LORELEI function affects seedling development given that LORELEI is expressed in eight-day-old seedlings. Here, we showed that despite a delay in initiation, lre-5/lre-5 embryos recover, becoming equivalent to the developing wild-type embryos beginning at 72 hours after pollination. Additionally, lre-5/lre-5 seed germination, and seedling and root development are indistinguishable from wild-type indicating that loss of LORELEI is tolerated, at least under standard growth conditions, in vegetative tissues.Key words: LORELEI, glycosylphosphatidylinositol (GPI)-anchored protein, embryogenesis, DD45, seed germination, primary and lateral root growth, seedling developmentDouble fertilization is unique to flowering plants. Upon female gametophyte reception of a pollen tube, the egg and central cells of the female gametophyte fuse with the two released sperm cells to form zygote and endosperm, respectively and initiate seed development.¹ The female gametophyte controls seed development by (1) repressing premature central cell or egg cell proliferation until double fertilization is completed,^1–3 (2) supplying factors that mediate early stages of embryo and endosperm development^1,4,5 and (3) regulating imprinting of genes required for seed development.^1,6The molecular mechanisms underlying female gametophyte control of early seed development are poorly understood. Although much progress has been made in identifying genes and mechanisms by which the female gametophyte represses premature central cell or egg cell proliferation until double fertilization is completed and regulates imprinting of genes required for seed development,^1,6 only a handful of female gametophyte-expressed genes that affect early embryo^7,8 and endosperm⁹ development after fertilization have been characterized. This is particularly important given that a large number of female gametophyte-expressed genes likely regulate early seed development.⁵We recently reported on a mutant screen for plants with reduced fertility and identification of a mutant that contained a large number of undeveloped ovules and very few viable seeds.¹⁰ TAIL-PCR revealed that this mutant is a new allele of LORELEI(LRE) [At4g26466].^10,11 Four lre alleles have been reported;¹¹ so, this mutant was designated lre-5.¹⁰ The Arabidopsis LORELEI protein contains 165 amino acids and possesses sequence features indicative of a glycosylphosphatidylinositol (GPI)-anchor containing cell surface protein. GPI-anchors serve as an alternative to transmembrane domains for anchoring proteins in cell membranes and GPI-anchored proteins participate in many functions including cell-cell signaling.¹²     

Therapeutic efficacy of Kalpaamruthaa on reactive oxygen/nitrogen species levels and antioxidative system in mammary carcinoma bearing rats

Reactive oxygen species play an important role in cancer and metastasis. Kalpaamruthaa is a modified Siddha preparation, which has been formulated in our laboratory. The preparation is an amalgamation of Semecarpus anacardium (SA), Emblica officinalis (EO) and honey, which gives an extra protectiveness to mammary carcinoma bearing animals (Sprague-Dawley stains were used for this study). The aim of our research is to determine the therapeutic efficiency of the drug with respect to lipid peroxidation and antioxidant status. The levels of lipid peroxides and antioxidant levels were measured in blood, and vital organs (liver, kidney and breast tissue) of control and experimental animals. In cancer condition, the LPO was increased and antioxidant levels were decreased. On drug (SA and KA) administration, decreased LPO and increased antioxidant levels were seen in control and experimental animals. This may be due to additive property of the drugs (SA, Emblica and honey), which possesses anticancer effect. The present study shows the good therapeutic efficacy of Kalpaamruthaa against mammary carcinoma.     

Apoptotic effect of Semecarpus anacardium nut extract on T47D breast cancer cell line

There is an increasing interest in identifying potent cancer-preventive and therapeutic agents against breast cancer. A great number of reports have in recent years dealt with anticancer characteristics of Semecarpus anacardium nut extract (SA). The majority of these studies has been targeted on the protective effect rendered to the living system rather than the preventive effect on cancer cells. SA was tested for its inhibitory effect on human breast cancer cells (T47D). Cytotoxicity analyses suggested that these cells had become apoptotic. SA was discovered to induce rapid Ca(2+) mobilization from intracellular stores of T47D cell line, and its cytotoxicity against T47D was well correlated with altered mitochondrial transmembrane potential. At the molecular level, these changes are accompanied by decrease in bcl(2) and increase in bax, cytochrome c, caspases and PARP cleavage, and ultimately by internucleosomal DNA fragmentation. Taken together, our results provide unprecedented evidence that SA triggers apoptotic signals in T47D cells.     

Augmented efficacy of tamoxifen in rat breast tumorigenesis when gavaged along with riboflavin, niacin, and CoQ10: effects on lipid peroxidation and antioxidants in mitochondria

Reactive oxygen species (ROS) play a major role in causing mitochondrial changes linked to cancer and metastasis. Uptake of antioxidants by tissue to reduce the ROS production could be instrumental in controlling cancer. Tamoxifen (TAM), a nonsteroidal anti-estrogen drug most used in the chemotherapy and chemoprevention of breast cancer. Riboflavin, niacin and coenzyme Q10 (CoQ10) are proved to be potent antioxidants and protective agents against many diseases including cancer. The objective of this research is to determine the therapeutic efficacy of combinatorial therapy on mammary carcinoma bearing rats in terms of the mitochondrial lipid peroxidation and antioxidant status especially MnSOD. Female albino rats of Sprague-Dawley strain were selected for the investigation. Mammary carcinoma was induced with 7,12-dimethyl benz(a)anthracene (DMBA: 25 mg), and the treatment was started by the oral administration of TAM (10 mg/kg body weight/day) along with riboflavin (45 mg/kg body weight/day), niacin (100 mg/kg body weight/day) and CoQ10 (40 mg/kg body weight/day) for 28 days. The levels of lipid peroxides, activities of enzymic and non-enzymic antioxidants were measured in the mitochondria isolated from the mammary gland and liver of control and experimental rats. Rats treated with DMBA showed an increase in mitochondrial lipid peroxidation (mammary gland 52.3%; liver 25.1%) accompanied by high malondialdehyde levels along with lowered activities of mitochondrial enzymic antioxidants [superoxide dismutase (mammary gland 19.9%; liver 24.8%), catalase (mammary gland 50%; liver 19.7%), glutathione peroxidase (mammary gland 47.8%; liver 31.1%)] and non-enzymic antioxidants [reduced glutathione (mammary gland 14.3%; liver 13.3%), Vitamin C (mammary gland 6.49%; liver 21.4%) and E (mammary gland 20.3%; liver 22.2%)]. Administration of combinatorial therapy restored lipid peroxide level and the activities of enzymic and non-enzymic antioxidants to near normalcy. In addition, antitumour activity was also found to be enhanced which is evident from the increased expression of tumour suppressor gene MnSOD thereby preventing cancer cell proliferation. These results suggested that TAM treatment is the most effective during co-administration of riboflavin, niacin and CoQ10 in terms of mitochondrial antioxidant and antitumour activity.