Binding of insulin-like growth factor-I (IGF-I) to primary cultures of chondrocytes from rat rib growth cartilage

Binding of insulin-like growth factor I (IGF-I) to cultured resting, proliferative and hypertrophic growth plate chondrocytes was investigated. The optimal binding conditions and the extent of degradation of the 125I-IGF-I at 20 degrees C were analyzed in a time-course study. The maximal binding without noticeable degradation was observed after 3 h. The binding of IGF-I to the proliferative cells was 2-fold higher than to the resting and the hypertrophic cells. On the proliferative chondrocytes two classes of receptors with different affinities were found. 125I-IGF-I could be displaced from the proliferative cells by unlabelled IGF-I, IGF-II and insulin, respectively. Half maximal binding was observed at 0.3 nmol/l (= 2.2 micrograms/l) of IGF-I, 4.3 nmol/l (= 32 micrograms/l) of IGF-II and 350 nmol/l (= 2000 micrograms/l) of insulin. No specific binding of human growth hormone (hGH) could be demonstrated. When binding of epidermal growth factor (EGF) to the proliferative cells was assessed, little, but specific binding was observed.     

OBATOCLAX and ABT-737 Induce ER Stress Responses in Human Melanoma Cells that Limit Induction of Apoptosis

Anti-apoptotic Bcl-2 family proteins, in particular, Mcl-1, are known to play a critical role in resistance of human melanoma cells to induction of apoptosis by endoplasmic reticulum stress and other agents. The present study examined whether the BH3 mimetics, Obatoclax and ABT-737, which inhibit multiple anti-apoptotic Bcl-2 family proteins, would overcome resistance to apoptosis. We report that both agents induced a strong unfolded protein response (UPR) and that RNAi knockdown of UPR signalling proteins ATF6, IRE1α and XBP-1 inhibited Mcl-1 upregulation and increased sensitivity to the agents. These results demonstrate that inhibition of anti-apoptotic Bcl-2 proteins by Obatoclax and ABT-737 appears to elicit a protective feedback response in melanoma cells, by upregulation of Mcl-1 via induction of the UPR. We also report that Obatoclax, but not ABT-737, strongly induces autophagy, which appears to play a role in determining melanoma sensitivity to the agents.     

Effects of IGF-I, EGF, and FGF on proteoglycans synthesized by fractionated chondrocytes of rat rib growth plate

The effects of insulin-like growth factor (IGF-I), epidermal growth factor (EGF), fibroblast growth factor (FGF), or 10% newborn calf serum (NCS) on the amount and structure of the proteoglycans synthesized by fractionated chondrocytes from rat growth plate were investigated. Proliferative cells (fraction II) or resting cells (fraction III) synthesized more proteoglycans than hypertrophic cells (fraction I). Addition of IGF-I to the cultures increased proteoglycan synthesis more than addition of EGF or FGF. EGF and FGF induced synthesis of proteoglycans of smaller molecular size with a lower proportion of aggregates. The size of the constituent glycosaminoglycan chains did not differ between control and growth factor-treated cells. The present study demonstrates that proteoglycan structure and synthesis are modified by growth factors to different extents, depending on the maturation stage of the target cells.     

Severe Aggression Among Female Pan troglodytes schweinfurthii at Gombe National Park, Tanzania

Aggression is generally more severe between males than between females because males gain greater payoffs from escalated aggression. Males that successfully defeat rivals may greatly increase their access to fertile females. Because female reproductive success depends on long-term access to resources, competition between females is often sustained but low key because no single interaction leads to a high payoff. Nonetheless, escalated aggression can sometimes immediately improve a female’s reproductive success. Resisting new immigrants can reduce feeding competition, and infanticide of other females’ young can increase a female’s access to resources. East African chimpanzees live in fission-fusion communities in which females occupy overlapping core areas. Growing evidence indicates that reproductive success correlates with core area quality, and that females compete for long-term access to core areas. Here we document 5 new cases of severe female aggression in the context of such competition: 2 attacks by resident females on an immigrant female, a probable intracommunity infanticide, and 2 attacks on a female and her successive newborn infants by females whose core areas overlapped hers. The cases provide further evidence that females are occasionally as aggressive as males. Factors influencing the likelihood and severity of such attacks include rank and size differences and the presence of dependable allies. Counterstrategies to the threat of female aggression include withdrawing from others around the time of parturition and seeking male protection. We also discuss an unusual case of a female taking the newborn infant of another, possibly to protect it from a potentially infanticidal female.     

An unusual incident of adoption in a wild chimpanzee (Pan troglodytes) population at Gombe National Park

Allomothering and adoption are well documented across primate species. Multiple hypotheses have been proposed to explain the evolution of such behavior according to the costs and benefits to the caregiver, mother, and infant. Permanent adoptions and allomothering have been observed in chimpanzees, but they typically involve the infants' siblings or nulliparous females. Here, I report a unique incident of adoption where an infant was adopted by its grandmother without the death of its mother. I conclude by considering how the adoption may have benefited the grandmother, mother, and infant.     

Nascent HDL formation by hepatocytes is reduced by the concerted action of serum amyloid A and endothelial lipase

Inflammation is associated with significant decreases in plasma HDL-cholesterol (HDL-C) and apoA-I levels. Endothelial lipase (EL) is known to be an important determinant of HDL-C in mice and in humans and is upregulated during inflammation. In this study, we investigated whether serum amyloid A (SAA), an HDL apolipoprotein highly induced during inflammation, alters the ability of EL to metabolize HDL. We determined that EL hydrolyzes SAA-enriched HDL in vitro without liberating lipid-free apoA-I. Coexpression of SAA and EL in mice by adenoviral vector produced a significantly greater reduction in HDL-C and apoA-I than a corresponding level of expression of either SAA or EL alone. The loss of HDL occurred without any evidence of HDL remodeling to smaller particles that would be expected to have more rapid turnover. Studies with primary hepatocytes demonstrated that coexpression of SAA and EL markedly impeded ABCA1-mediated lipidation of apoA-I to form nascent HDL. Our findings suggest that a reduction in nascent HDL formation may be partly responsible for reduced HDL-C during inflammation when both EL and SAA are known to be upregulated.     

Statin Therapy Is Associated with Improved Survival in Patients with Non-Serous-Papillary Epithelial Ovarian Cancer: A Retrospective Cohort Analysis

Aim

To determine whether statin use is associated with improved epithelial ovarian cancer (OvCa) survival.

Methods

This is a single-institution retrospective cohort review of patients treated for OvCa between 1992 and 2013. Inclusion criteria were International Federation of Gynecology and Obstetrics (FIGO) stage I–IV OvCa. The primary exposures analyzed were hyperlipidemia and statin use. The primary outcomes were progression-free survival (PFS) and disease-specific survival (DSS).

Results

442 patients met inclusion criteria. The cohort was divided into three groups: patients with hyperlipidemia who used statins (n = 68), patients with hyperlipidemia who did not use statins (n = 28), and patients without hyperlipidemia (n = 346). OvCa outcomes were evaluated. When we analyzed the entire cohort, we found no significant differences in PFS or DSS among the groups. The median PFS for hyperlipidemics using statins, hyperlipidemics not using statins, and non-hyperlipidemics was 21.7, 13.6, and 14.7 months, respectively (p = 0.69). Median DSS for hyperlipidemics using statins, hyperlipidemics not using statins, and non-hyperlipidemics was 44.2, 75.7, and 41.5 months, respectively (p = 0.43). These findings did not change after controlling for confounders. However, a secondary analysis revealed that, among patients with non-serous-papillary subtypes of OvCa, statin use was associated with a decrease in hazards of both disease recurrence (adjusted HR = 0.23, p = 0.02) and disease-specific death (adjusted HR = 0.23, p = 0.04). To augment the findings in the retrospective cohort, the histology-specific effects of statins were also evaluated in vitro using proliferation assays. Here, statin treatment of cell lines resulted in a variable level of cytotoxicity.

Conclusion

Statin use among patients with non-serous-papillary OvCa was associated with improvement in both PFS and DSS.     

The Role of TIR-NBS and TIR-X Proteins in Plant Basal Defense Responses

Toll/interleukin receptor (TIR) domain-containing proteins encoded in the Arabidopsis (Arabidopsis thaliana) genome include the TIR-nucleotide binding site (TN) and TIR-unknown site/domain (TX) families. We investigated the function of these proteins. Transient overexpression of five TX and TN genes in tobacco (Nicotiana benthamiana) induced chlorosis. This induced chlorosis was dependent on ENHANCED DISEASE RESISTANCE1, a dependency conserved in both tobacco and Arabidopsis. Stable overexpression transgenic lines of TX and TN genes in Arabidopsis produced a variety of phenotypes associated with basal innate immune responses; these were correlated with elevated levels of salicylic acid. The TN protein AtTN10 interacted with the chloroplastic protein phosphoglycerate dehydrogenase in a yeast (Saccharomyces cerevisiae) two-hybrid screen; other TX and TN proteins interacted with nucleotide binding-leucine-rich repeat proteins and effector proteins, suggesting that TN proteins might act in guard complexes monitoring pathogen effectors.Innate immunity is a primary defense mechanism in plants that functions to protect against a variety of biotic stresses (Eitas and Dangl, 2010). The plant basal immune system comprises pattern or pathogen recognition receptors that can recognize a variety of plant pathogens by identifying specific pathogen-associated molecular patterns (PAMPs; Tsuda and Katagiri, 2010). This recognition of PAMPs by plant pattern recognition receptors triggers PAMP-triggered immunity or plant basal immunity (Jones and Dangl, 2006; Zipfel, 2008). Well-known PAMPs or microbe-associated molecular patterns recognized by plants include bacterial flagellin, cold shock proteins, and elongation factor Tu. To suppress PAMP-triggered immunity, plant pathogens secrete an array of virulence factors such as type III effector proteins, while plant resistance (R) proteins function to recognize the effector molecules (Römer et al., 2009; Lewis et al., 2010; Tsuda and Katagiri, 2010; Zhang et al., 2012). Specific recognition of a pathogen effector by a plant R protein triggers a second type of immune response called effector-triggered immunity, resulting in an incompatible reaction (Qi et al., 2011; Sohn et al., 2012; Tahir et al., 2012).The most commonly known plant R proteins are the nucleotide-binding (NB) site Leucine-rich repeat (LRR) proteins that plants use to detect effector proteins. The NB is often called NB-ARC because of sequence similarities to the human apoptotic protease-activating factor APAF1 and Caenorhabditis elegans homolog CELL DEATH PROTEIN4 (Lukasik and Takken, 2009). Plant NB-LRR proteins often also have, at the N terminus, a Toll/Interleukin-1 receptor (TIR) or coiled coil (CC) domain (Meyers et al., 2003). In animal TIR proteins, this domain is more commonly located at the C terminus and is linked by a transmembrane domain to an N-terminal LRR domain (Torto et al., 2002). In Drosophila spp. and other microbes, a TIR domain has been shown to play an important role in the activation of antifungal immune responses (Jenkins and Mansell, 2010). Toll-like receptors (TLRs) perform an integral role in the activation of antimicrobial responses in many animals (Radhakrishnan and Splitter, 2010).In plants, two additional TIR-containing protein families, TIR-NB site (TN) and TIR-unknown/random (TX), were identified, which are distinct from the longer TIR-NB-LRR (TNL) R protein homologs (Meyers et al., 2002). TN proteins contain TIR and NBS domains but lack LRRs, while TX proteins lack both NBS and LRR domains, yet often have a small and variable C-terminal domain (Meyers et al., 2002). In the Arabidopsis (Arabidopsis thaliana) ecotype Columbia (Col-0) genome, there are 30 TX genes and 21 TN genes (Meyers et al., 2003). The crystal structure of a TIR domain from an Arabidopsis TN protein (At1g72930/{"type":"entrez-protein","attrs":{"text":"NP_177436","term_id":"15218629","term_text":"NP_177436"}}NP_177436) contains a compact globular fold resembling the mammalian (TLR1 and MYELOID DIFFERENTIATION PRIMARY RESPONSE GENE88 [MYD88]) and bacterial TIR domain proteins (Chan et al., 2010). Although plant TIR domains share less than 20% sequence identity with the human TLR domains, the structures of the TIR domain in plants, mammalian TLRs, and bacterial TIR domain proteins have strong similarity (Chan et al., 2010).A high proportion of TX and TN genes were previously reported to be in complex clusters with TNL genes; these clusters were found to be duplicated to multiple locations in the genome (Meyers et al., 2002). The existence of genetically linked pairs or sets of genes such as RESISTANCE TO PERONOSPORA PARASITICA2A (RPP2A)-RPP2B, RESISTANCE TO PSEUDOMONAS SYRINGAE1 (RPS1)-RPS4, LEAF RUST RESISTANCE GENE10 (LR10)-RESISTANCE GENE ANALOGUE2 (RGA2), RICE BLAST RESISTANCE GENE AT PIK LOCUS1 (PIKM-1)-TS-PIKM2-TS, and RICE BLAST RESISTANCE GENE AT PI LOCUS1 (PI5-1)-PI5-2 in the genomes and their role in disease resistance suggests that these linked genes are required to effect a defense response in plants (Eitas and Dangl, 2010). The genomic pairing of the TNL genes with TX or TN genes suggests a role of the tightly linked TN protein in the function of its cognate TNL protein or proteins (and vice versa).The specific direct or indirect interaction between an R gene and a corresponding avirulence (Avr) gene in the characterized pairs of interaction resulted in an immune response in the form of localized programmed cell death, called the hypersensitive response (HR; Burch-Smith et al., 2007; Caplan et al., 2008). The recognition of avirulence proteins from pathogens by the cognate R proteins induces a cascade of changes that increases the levels of salicylic acid (SA), jasmonic acid (JA), phenyl ammonium lyase, and systemin (Liu et al., 2010). The production of several of these biochemical signals is known to trigger multiple convergent ‘R’-gene signaling pathways, leading to programmed cell death and further changes in gene expression patterns (Vlot et al., 2008a, 2008b). Structure function analysis of Arabidopsis R proteins RPS4 (Zhang et al., 2004) and RPP1A (Michael Weaver et al., 2006) have shown that TIR and NBS domains of the proteins without the LRR domain (TNL truncations) could be sufficient to induce HR. Studies using overexpression of plant R genes (particularly the truncated TNL genes) suggest that the TIR and NBS domains by themselves might be sufficient to induce HR and to initiate plant defense responses (Michael Weaver et al., 2006; Swiderski et al., 2009).In this study, we present experimental and computational data that are collectively consistent with a role for Arabidopsis TX and TN proteins in plant defenses. For example, the ability of the TX and TN genes to induce HR responses upon transient expression is dependent on ENHANCED DISEASE RESISTANCE1 (EDS1). This EDS1 dependency in induced HR was demonstrated in both tobacco (Nicotiana benthamiana) and in Arabidopsis. Stable transgenic overexpression in Arabidopsis of TX and TN genes resulted in a variety of phenotypes involved with basal innate immune responses that are dependent on SA. We also demonstrated the interaction of TX and TN proteins with plant pathogenic elicitor proteins and other plant signal transduction proteins.