Defective chaperone-mediated autophagy is a hallmark of joint disease in patients with knee osteoarthritis.

OBJECTIVE: Defects in autophagy contribute to joint aging and Osteoarthritis (OA). Identifying specific autophagy types could be useful for developing novel treatments for OA. DESIGN: An autophagy-related gene array was performed in blood from non-OA and knee OA subjects from the Prospective Cohort of A Coruña (PROCOAC). The differential expression of candidate genes was confirmed in blood and knee cartilage and a regression analysis was performed adjusting for age and BMI. HSP90A, a chaperone mediated autophagy (CMA) marker was validated in human knee joint tissues, as well as, in mice with aging-related and surgically-induced OA. The consequences of HSP90AA1 deficiency were evaluated on OA pathogenesis. Finally, the contribution of CMA to homeostasis was studied by assessing the capacity to restore proteostasis upon ATG5-mediated macroautophagy deficiency and genetic HSP90AA1 overexpression. RESULTS: 16 autophagy-related genes were significantly down-regulated in blood from knee OA subjects. Validation studies showed that HSP90AA1 was down-regulated in blood and human OA cartilage and correlated with risk incidence of OA. Moreover, HSP90A was reduced in human OA joints tissues and with aging and OA in mice. HSP90AA1 knockdown was linked to defective macroautophagy, inflammation, oxidative stress, senescence and apoptosis. However, macroautophagy deficiency increased CMA, highlighting the CMA-macroautophagy crosstalk. Remarkably, CMA activation was sufficient to protect chondrocytes from damage. CONCLUSIONS: We show that HSP90A is a key chaperone for chondrocyte homeostasis, while defective CMA contributes to joint damage. We propose that CMA deficiency is a relevant disease mechanism and could represent a therapeutic target for OA.

PGA1-induced apoptosis involves specific activation of H-Ras and N-Ras in cellular endomembranes.

The cyclopentenone prostaglandin A1 (PGA1) is an inducer of cell death in cancer cells. However, the mechanism that initiates this cytotoxic response remains elusive. Here we report that PGA1 triggers apoptosis by a process that entails the specific activation of H- and N-Ras isoforms, leading to caspase activation. Cells without H- and N-Ras did not undergo apoptosis upon PGA1 treatment; in these cells, the cellular demise was rescued by overexpression of either H-Ras or N-Ras. Consistently, the mutant H-Ras-C118S, defective for binding PGA1, did not produce cell death. Molecular analysis revealed a key role for the RAF-MEK-ERK signaling pathway in the apoptotic process through the induction of calpain activity and caspase-12 cleavage. We propose that PGA1 evokes a specific physiological cell death program, through H- and N-Ras, but not K-Ras, activation at endomembranes. Our results highlight a novel mechanism that may be of potential interest for tumor treatment.

Evaluation of the risk factors of asymptomatic vertebral fractures in postmenopausal women with osteopenia at the femoral neck.

OBJECTIVES: To identify risk factors of asymptomatic vertebral fracture (aVF) in postmenopausal women with osteopenia at the femoral neck and to evaluate the association between the number of aVFs and the risk of major and hip osteoporotic fracture calculated with the FRAX(®) algorithm. STUDY DESIGN: Epidemiological case-series study with data collected transversally. RESULTS: 728 postmenopausal women with osteopenia were included: 284 (39.0%) had aVF, of whom 200 (70.4%) had prior fragility fractures (FF). The likelihood of having an osteoporotic fracture in the next 10 years increased significantly with the number of aVF. The percentage of women with height loss, which was assessed as the difference between the greatest height reported by participants and that measured at inclusion, was higher in women with an aVF (OR 3.77, 95% CI 2.75-5.16, p<0.05). Multivariate analysis showed that prior FF, height loss and race were factors associated with the presence of aVF. CONCLUSIONS: In this group of postmenopausal women with osteopenia at the femoral neck, the presence of an aVF correlated with a higher risk of estimated major osteoporotic and hip fractures as calculated using the FRAX(®) algorithm. Height loss and prior FF were associated with the presence of aVF.

Highly polymorphic in silico-derived microsatellite loci in the potato-infecting fungal pathogen Rhizoctonia solani anastomosis group 3 from the Colombian Andes.

Fourteen polymorphic microsatellite DNA markers derived from the draft genome sequence of Rhizoctonia solani anastomosis group 3 (AG-3), strain Rhs 1AP, were designed and characterized from the potato-infecting soil fungus R. solani AG-3. All loci were polymorphic in two field populations collected from Solanum tuberosum and S. phureja in the Colombian Andes. The total number of alleles per locus ranged from two to seven, while gene diversity (expected heterozygosity) varied from 0.11 to 0.81. Considering the variable levels of genetic diversity observed, these markers should be useful for population genetic analyses of this important dikaryotic fungal pathogen on a global scale.

Praziquantel treatment of muscle Taenia solium cysticercosis. 4. Reversible in vitro effect.

The in vitro effect of Praziquantel (PZQ) on Taenia solium cysticerci was analyzed. The oxygen consumption rate of the parasites was inhibited and the release of proteins was enhanced, but no statistically significant differences were found between the control group and the experimental groups. The drug had a significant, dose-dependent negative effect on the evagination ability of the larvae; 50% effect was seen at concentrations of between 10(-9) and 10(-8) M PZQ. The drug also induced morphological disturbances in the tegument of the worm and of the bladder wall. Finally, a very drastic effect was the induction of spastic paralysis in evaginated cysticerci at high drug doses and of flaccid paralysis at lower PZQ concentrations. The dose inducing these effects was various orders of magnitude lower than that inhibiting the evagination ability of intact cysts. Moreover, the latter effect was reversible after had been washed out the drug and the parasites had been cultured. We suggest that PZQ alters the Ca2+ flux in T. solium as it does in other helminths. Furthermore, we corroborated the protective role of the bladder for the invaginated worm. Finally, we think that in vivo the drug must act synergistically with the immune system components so as to eliminate the parasite.