Sialic acids Neu5Ac and KDN in adipose tissue samples from individuals following habitual vegetarian or non-vegetarian dietary patterns.

Sialic acids (Sias) are a class of sugar molecules with a parent nine-carbon neuraminic acid, generally present at the ends of carbohydrate chains, either attached to cellular surfaces or as secreted glycoconjugates. Given their position and structural diversity, Sias modulate a wide variety of biological processes. However, little is known about the role of Sias in human adipose tissue, or their implications for health and disease, particularly among individuals following different dietary patterns. The goal of this study was to measure N-Acetylneuraminic acid (Neu5Ac), N-Glycolylneuraminic acid (Neu5Gc), and 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN) concentrations in adipose tissue samples from participants in the Adventist Health Study-2 (AHS-2) and to compare the abundance of these Sias in individuals following habitual, long-term vegetarian or non-vegetarian dietary patterns. A method was successfully developed for the extraction and detection of Sias in adipose tissue. Sias levels were quantified in 52 vegans, 56 lacto-vegetarians, and 48 non-vegetarians using LC-MS/MS with Neu5Ac-D-1,2,3-13C3 as an internal standard. Dietary groups were compared using linear regression. Vegans and lacto-ovo-vegetarians had significantly higher concentrations of Neu5Ac relative to non-vegetarians. While KDN levels tended to be higher in vegans and lacto-ovo-vegetarians, these differences were not statistically significant. However, KDN levels were significantly inversely associated with body mass index. In contrast, Neu5Gc was not detected in human adipose samples. It is plausible that different Neu5Ac concentrations in adipose tissues of vegetarians, compared to those of non-vegetarians, reflect a difference in the baseline inflammatory status between the two groups. Epidemiologic studies examining levels of Sias in human adipose tissue and other biospecimens will help to further explore their roles in development and progression of inflammatory conditions and chronic diseases.

Prevalence and factors associated with self-reported anxiety in adults during the COVID-19 pandemic in Argentina, Brazil, Peru, Mexico, and Spain: A cross-sectional Ibero-American study.

The present study evaluated the factors associated with the perception of anxiety during the first wave of covid-19 in Ibero-American countries. This cross-sectional study was carried out with 5.845 participants of both sexes, over 18 years of age, and residents of four Latin American countries-Argentina (16.7%), Brazil (34.5%), Mexico (11.1%), and Peru (17.5%), and one European country-Spain (20.1%). Data were collected in 2020, between April 1st and June 30th in Spain and between July 13th and September 26th in the Latin American countries. We used an online questionnaire with sociodemographic, lifestyle, self-reported anxiety, and covid-19 related questions. The chi-square statistical test and Multivariate logistic regressions were performed to analyze the factors associated with self-reported anxiety. The presence of self-reported anxiety was found in 63.8% of the participants during the isolation period. The association occurred mainly in women (OR:1.52; CI: 1.3-1.7), those aged 18 to 29 years (OR: 1.51; CI: 1.2-1.9) and 30 to 49 years (OR: 1.56; CI: 1.3-1.9), residents of Argentina (OR: 1.55 CI: 1.2-1.9), Brazil (OR: 2.38; CI: 2.0-2.8) and Mexico (OR: 1.52; CI: 1.2-1.9), those who gained weight (OR:1.71 CI: 1.5-1.9) or lost weight (OR: 1.40; CI: 1.2-1.6), and those who reported having slept more (OR: 1.56; CI: 1.3-1.8) or less (OR: 2.89; CI: 2.5-3.4). We conclude that the prevalence of self-reported anxiety in Ibero-American countries was high during the period studied, highlighting a higher likelihood of its occurrence in Brazil, in those who began to sleep less and gained weight.

Development and Usability Study of an Open-Access Interviewer-Administered Automated 24-h Dietary Recall Tool in Argentina: MAR24.

Background: Latin American countries show a fast-growing rate of non-communicable diseases (NCDs) and diet is a critical risk factor that must be properly assessed. Automated dietary assessment tools to collect 24-h dietary recalls (24HR) are lacking in Argentina. Objective: This study aimed to develop an open-access automated tool (MAR24) for collecting 24HR using a multiple pass method and a database containing foods and recipes commonly consumed in Argentina. Methods: MAR24 was developed based on data from 1,285 24HR provided by male and female participants aged 18 to 68 years from the six Argentinian geographical regions. The main structure and interface of the tool were designed using Visual Basic for Applications programming language in Excel Microsoft Office 365, integrating the five steps of the United States Department of Agriculture (USDA) Automated Multiple-Pass Method (AMPM) for the application of 24HR in Spanish. The tool underwent alpha testing and expert assessment to address structural and usability issues. Critical feedback and face validation from researchers and experienced dietitians, and repeated testing to collect 24HR were used to adjust and improve the tool. Results: A total of 968 food items and 100 standard Argentinian recipes were added to its database. MAR24 allows the estimation of the nutrient profile of dietary intake. The analytic food composition includes energy and 50 nutrients including water, macronutrients, total dietary fiber, total sugar, 10 minerals, 19 vitamins, eight fatty acids, cholesterol, ethyl alcohol, caffeine, and theobromine. MAR24 includes a user manual and technical manual to guide users to apply changes (e.g., add foods or recipes, or change food designation according to local terms) to fit different research and clinical applications. Conclusions: MAR24 is the first tool that uses the AMPM methodology for 24HR applications in Argentina. The tool may be used in clinical practice and clinical trials for monitoring purposes, and in validation of food frequency questionnaires (FFQ) for nutritional epidemiology studies addressing dietary-associated risk factors for NCDs.

Diet and Lifestyle Changes During the COVID-19 Pandemic in Ibero-American Countries: Argentina, Brazil, Mexico, Peru, and Spain.

This study aimed to evaluate changes in dietary and lifestyle habits during the period of confinement due to the first wave of the COVID-19 pandemic in Ibero-American countries. A cross-sectional investigation was conducted with 6,325 participants of both genders (68% women), over 18 years of age and from five countries: Brazil (N = 2,171), Argentina (N = 1,111), Peru (N = 1,174), Mexico (N = 686), and Spain (N = 1,183). Data were collected during the year 2020, between April 01 and June 30 in Spain and between July 13 and September 26, in the other countries studied using a self-administered online survey designed for the assessment of sociodemographic, employment, physical activity, health status, and dietary habits changes. Most participants (61.6%), mainly those from Spain, remained constant, without improving or worsening their pattern of food consumption. Among those who changed, a pattern of better eating choices prevailed (22.7%) in comparison with those who changed toward less healthy choices (15.7%). Argentina and Brazil showed the highest proportion of changes toward a healthier pattern of food consumption. Peruvians and Mexicans were less likely to make healthy changes in food consumption (OR: 0.51; 95% CI: 0.4-0.6 and OR: 0.69; 95% CI: 0.4-0.8, respectively), when compared to Argentinians. Most respondents did not change their pattern of meal consumption, but those who did reduced their consumption of main meals and increased intake of small meals and snacks. Although most participants affirmed to be doing physical activity at home, about one-half reported perception of weight gain. Individuals with alterations in sleep pattern (either by increasing or decreasing sleep time) were more likely to change their diets to a healthier pattern. In contrast, individuals with confirmed diagnosis of COVID-19 and those who reported feeling anxious were more likely to perform changes to a less healthy eating pattern (OR: 1.72; 95% CI: 1.2-2.3 and OR: 1.21; 95% CI: 1.1-1.4, respectively). In conclusion, although most participants remained constant in their eating habits, lifestyle changes and anxiety feelings were reported. Among those who changed patterns of food consumption, healthier choices prevailed, with differences between countries. However, there were alterations in the distribution of meals, with higher consumption of snacks and small meals. These results can be used to guide policies to prevent deleterious consequences that may affect the incidence of chronic diseases.

Reception of Dietary and Other Health-Related Lifestyle Advice to Address Non-communicable Diseases in a Primary Care Context: A Mixed-Method Study in Central Argentina.

An effective way to address risk factors for non-communicable chronic diseases (NCD) and reduce healthcare costs is by using sound health-related advice (HRA) to promote healthy lifestyle habits. In Argentina, however, few studies have examined the context in which HRA is communicated and undertaken by patients at the primary care level. In this study, we assessed the reception of HRA using a mixed-method approach in a central area of Argentina. A total of 1,044 participants from the community were contacted and sociodemographic characteristics, health-related lifestyle factors, and medical history were collected. A calendar with health messages was provided to participants and its usage was assessed after 1 year. Additionally, semi-structured interviews were conducted with 34 patients attending a local primary healthcare center. The results show that HRA was given more frequently to individuals with higher mean age, lower educational level, and to females. Participants with a chronic health condition are at a higher chance of receiving advice to reduce salt intake and maintain a healthy weight. Dietary advice is offered along with other lifestyle recommendations. The use of alcohol and tobacco is usually addressed together. HRA was primarily received in the context of an NCD diagnosis and advice was directed, especially, to risky behaviors. The HRA to increase the intake of fruits and vegetables was mentioned less frequently. Patients at the healthcare center greatly appreciated receiving an HRA, especially when given in a tailored, written, and detailed form, and acknowledged its importance to prevent or control a chronic health condition as part of the medical treatment but showed concern regarding the ability to fully incorporate the advice. Lifestyle recommendations are highly appreciated by patients but are still underutilized since they are offered mostly in the context of illness. The health calendar was shown to be useful to complement health intervention programs at the community level. The findings of our study underscore the acknowledged value of HRA by participants to tackle the risk factors of chronic diseases. If properly used HRA constitutes a simple and highly valued tool to help address patient's needs to prevent and control NCD in Argentina.

Healthy Vegan Lifestyle Habits among Argentinian Vegetarians and Non-Vegetarians.

Although current research has contributed to the promotion of whole-food plant-based diets, few studies have examined healthy vegan dietary and lifestyle factors, especially in South America. Therefore, we aimed at investigating the adherence to healthy vegan lifestyle habits among Argentinian vegetarians and omnivorous, using a recently developed vegetarian lifestyle index adapted to the vegan dietary pattern. Also, accessibility of vegetarian foods, and the proportion of household income spent on food were assessed in a cross-sectional approach with 1454 participants. The population was comprised of females (84.9%), singles (55.0%), young-adults (mean age 32.1, standard deviation (SD) = 13.6), employed (50.8%), with high educational levels (50.4%), and low prevalence of both tobacco smoking (7.0%) and frequent alcohol consumption (7.6%). The mean score of adherence to healthy vegan lifestyle habits was 6.64 (SD = 1.72), with higher scores indicating better adherence. Non-vegetarians (5.75; 95% confidence interval (CI), 5.61⁻5.89) had a significantly lower adjusted mean score compared to semi-(6.32; 95% CI, 6.17⁻6.47), pesco-(6.99; 95% CI, 6.59⁻7.39), lacto-ovo-vegetarians (7.10; 95% CI, 6.96⁻7.24), as well as vegans (8.59; 95% CI, 8.35⁻8.83). The mean proportion of household income spent on food was significantly lower among vegans compared with other dietary patterns. The whole studied population showed a low consumption of whole grains, legumes, vegetables, nuts, and seeds. Although vegans showed a better diet and lifestyle pattern there is a need to improve eating and lifestyle habits to address risk factors for non-communicable diseases in Argentina.

Long-Term Dietary Intake of Chia Seed Is Associated with Increased Bone Mineral Content and Improved Hepatic and Intestinal Morphology in Sprague-Dawley Rats.

Chia seeds (Salvia hispanica) provide an unusually high content of α-linolenic acid with several potential health benefits, but few studies have examined the long-term intake of n-3 fatty acid-rich plant foods such as chia. In this work, we investigated some of the effects of a diet containing 10% chia seeds versus a conventional isocaloric diet for 10 and 13 months on body measurements, musculoskeletal system, the liver, and the intestines of 20 male Sprague-Dawley rats assigned into two groups. The n-6/n-3 ratios for the control and chia diets were 7.46 and 1.07, respectively. For the first 10 months of the diet, the body parameters and weights were similar, but at 13 months, the bone mineral content (BMC) of the chia-fed rats was significantly higher than that of the controls whether in total or proximal areas of the left tibia. Also, significant positive correlations were found between the age of the chia group and the bone mineral density, BMC, weight of the musculoskeletal system, final body weight, and skin weight. Liver and intestinal examinations showed improved morphology associated with lower lipid deposit in hepatocytes and increased intestinal muscle layers and crypt size in the chia group. This study provides new data suggesting the potential benefits associated with the long-term intake of chia seeds.

Knowledge about epilepsy in university health students: A multicenter study.

Even with economic development and improvements in health care around the world, it is estimated that nowadays, 50 million people have epilepsy. It is one of the most prevalent neurological diseases, yet it is still surrounded by prejudice, stigma, lack of awareness, and wrong attitudes of the population towards the disease. The aim of this study was to evaluate and compare the knowledge about epilepsy in health students from different countries: Brazil, Argentina, Portugal, United States, and South Africa. Students were asked to complete a survey regarding knowledge about epilepsy (the Epilepsy Knowledge Questionnaire). One hundred and two students participated, 62.2% of them were female. Portuguese students had significantly higher values than the American ones (p=0.025). Regarding the medical aspects, on average, students hit 63.8% of the questions, and the students from Portugal had significantly higher average than the ones from the United States (p=0.0007). Statements with lower percent of correct answers were about pathophysiology, medication, and treatment of the disease. There were no differences between the scores obtained by the students of each country in the social aspects of the disease. Statements with higher percent of mistakes were about sports practice, labor, proceedings in case of convulsion, and ability to drive vehicles. General knowledge of senior health students about epilepsy was considered low, however, regarding the medical aspects of the disease, students from Brazil and Portugal exhibited a slightly superior knowledge. Changing the way of seeing and treating people with epilepsy brings, as a consequence, increased opportunities for these people in different sectors of society.

Risk Factors for Chronic Diseases and Multimorbidity in a Primary Care Context of Central Argentina: A Web-Based Interactive and Cross-Sectional Study.

Global health agencies estimate an increase of chronic diseases in South America. Nevertheless, few studies have investigated chronic diseases and their risk factors in the perspective of multimorbidity. This research aimed to identify these aspects in a primary health care setting of central Argentina. The Pan America version of the STEP wise approach surveillance (STEPS) instrument of the World Health Organization was applied to 1044 participants, 365 men and 679 women, with a mean age of 43 years. High prevalence of overweight (33.5%), obesity (35.2%), central obesity (54%), dyslipidemia (43.5%), metabolic syndrome (21.1%), low intake of fruit and vegetables (91.8%), low levels of physical activity (71.5%), risky alcohol consumption (28%), and smoking (22.5%) were detected. Hypertension and diabetes were the most prevalent chronic conditions and the total prevalence of multimorbidity was 33.1%, with 2, 3, 4, 5 and 6 chronic conditions found in 19.9%, 9.1%, 2.6%, 1.1% and 0.4% of the population, respectively. Multimorbidity affected 6.4% of the young, 31.7% of the adults, and 60.6% of the elderly, and was more prevalent among women, and in participants with lower levels of education. Having multimorbidity was significantly associated with obesity, central obesity, and higher concentrations of total blood cholesterol, low-density lipoprotein cholesterol, triglycerides, and glucose. A website was made available to the participants in order to share the experimental results and health-promoting information.

Food Habits, Lifestyle Factors, and Risk of Prostate Cancer in Central Argentina: A Case Control Study Involving Self-Motivated Health Behavior Modifications after Diagnosis.

Cancer is the second most important non-communicable disease worldwide and disproportionately impacts low- to middle-income countries. Diet in combination with other lifestyle habits seems to modify the risk for some cancers but little is known about South Americans. Food habits of Argentinean men pre- and post-diagnosis of prostate cancer (n = 326) were assessed along with other lifestyle factors. We studied whether any of the behaviors and risk factors for prostate cancer were found in men with other cancers (n = 394), compared with control subjects (n = 629). Before diagnosis, both cases reported a greater mean consumption of meats and fats and lower intakes of fruits, green vegetables, cruciferous vegetables, legumes, nuts, seeds, and whole grains than the controls (all p < 0.001). After diagnosis, cases significantly reduced the intake of meats and fats, and reported other dietary modifications with increased consumption of fish, fruits (including red fruits in prostate cancer), cruciferous vegetables, legumes, nuts, and black tea (all p < 0.001). Additional lifestyle aspects significantly predominant in cases included a reduced quality of sleep, emotional stress, low physical activity, tobacco smoking, alcohol consumption, living in rural areas, and being exposed to environmental contaminants. Argentinian men were predisposed to modify their unhealthy dietary habits and other lifestyle factors after cancer diagnosis.

Docosahexanoic acid antagonizes TNF-α-induced necroptosis by attenuating oxidative stress, ceramide production, lysosomal dysfunction, and autophagic features.

OBJECTIVE: It was previously reported that docosahexanoic acid (DHA) reduces TNF-α-induced necrosis in L929 cells. However, the mechanisms underlying this reduction have not been investigated. The present study was designed to investigate cellular and biochemical mechanisms underlying the attenuation of TNF-α-induced necroptosis by DHA in L929 cells. METHODS: L929 cells were pre-treated with DHA prior to exposure to TNF-α, zVAD, or Necrostatin-1 (Nec-1). Cell death and survival were assessed by MTT and caspase activity assays, and microscopic visualization. Reactive oxygen species (ROS) were measured by flow cytometry. C16- and C18-ceramides were measured by mass spectrometry. Lysosomal membrane permeabilization (LMP) was evaluated by fluorescence microscopy and flow cytometry using Acridine Orange. Cathepsin L activation was evaluated by immunoblotting and fluorescence microscopy. Autophagy was assessed by immunoblotting of LC3-II and Beclin. RESULTS: Exposure of L929 cells to TNF-α alone for 24 h induced necroptosis, as evidenced by the inhibition of cell death by Nec-1, absence of caspase-3 activity and Lamin B cleavage, and morphological analysis. DHA attenuated multiple biochemical events associated with TNF-α-induced necroptosis, including ROS generation, ceramide production, lysosomal dysfunction, cathepsin L activation, and autophagic features. DHA also attenuated zVAD-induced necroptosis but did not attenuate the enhanced apoptosis and necrosis induced by the combination of TNF-α with Actinomycin D or zVAD, respectively, suggesting that its protective effects might be limited by the strength of the cell death insult induced by TNF-α. CONCLUSIONS: DHA effectively attenuates TNF-α-induced necroptosis and autophagy, most likely via its ability to inhibit TNF-α-induced sphingolipid metabolism and oxidative stress. These results highlight the role of this Omega-3 fatty acid in antagonizing inflammatory cell death.

Lipotoxicity-mediated cell dysfunction and death involve lysosomal membrane permeabilization and cathepsin L activity.

Lipotoxicity, which is triggered when cells are exposed to elevated levels of free fatty acids, involves cell dysfunction and apoptosis and is emerging as an underlying factor contributing to various pathological conditions including disorders of the central nervous system and diabetes. We have shown that palmitic acid (PA)-induced lipotoxicity (PA-LTx) in nerve growth factor-differentiated PC12 (NGFDPC12) cells is linked to an augmented state of cellular oxidative stress (ASCOS) and apoptosis and that these events are inhibited by docosahexanoic acid (DHA). The mechanisms of PA-LTx in nerve cells are not well understood, but our previous findings indicate that it involves ROS generation, mitochondrial membrane permeabilization (MMP), and caspase activation. The present study used nerve growth factor differentiated PC12 cells (NGFDPC12 cells) and found that lysosomal membrane permeabilization (LMP) is an early event during PA-induced lipotoxicity that precedes MMP and apoptosis. Cathepsin L, but not cathepsin B, is an important contributor in this process since its pharmacological inhibition significantly attenuated LMP, MMP, and apoptosis. In addition, co-treatment of NGFDPC12 cells undergoing lipotoxicity with DHA significantly reduced LMP, suggesting that DHA acts by antagonizing upstream signals leading to lysosomal dysfunction. These results suggest that LMP is a key early mediator of lipotoxicity and underscore the value of interventions targeting upstream signals leading to LMP for the treatment of pathological conditions associated with lipotoxicity.

Docetaxel-induced prostate cancer cell death involves concomitant activation of caspase and lysosomal pathways and is attenuated by LEDGF/p75.

BACKGROUND: Hormone-refractory prostate cancer (HRPC) is characterized by poor response to chemotherapy and high mortality, particularly among African American men when compared to other racial/ethnic groups. It is generally accepted that docetaxel, the standard of care for chemotherapy of HRPC, primarily exerts tumor cell death by inducing mitotic catastrophe and caspase-dependent apoptosis following inhibition of microtubule depolymerization. However, there is a gap in our knowledge of mechanistic events underlying docetaxel-induced caspase-independent cell death, and the genes that antagonize this process. This knowledge is important for circumventing HRPC chemoresistance and reducing disparities in prostate cancer mortality. RESULTS: We investigated mechanistic events associated with docetaxel-induced death in HRPC cell lines using various approaches that distinguish caspase-dependent from caspase-independent cell death. Docetaxel induced both mitotic catastrophe and caspase-dependent apoptosis at various concentrations. However, caspase activity was not essential for docetaxel-induced cytotoxicity since cell death associated with lysosomal membrane permeabilization still occurred in the presence of caspase inhibitors. Partial inhibition of docetaxel-induced cytotoxicity was observed after inhibition of cathepsin B, but not inhibition of cathepsins D and L, suggesting that docetaxel induces caspase-independent, lysosomal cell death. Simultaneous inhibition of caspases and cathepsin B dramatically reduced docetaxel-induced cell death. Ectopic expression of lens epithelium-derived growth factor p75 (LEDGF/p75), a stress survival autoantigen and transcription co-activator, attenuated docetaxel-induced lysosomal destabilization and cell death. Interestingly, LEDGF/p75 overexpression did not protect cells against DTX-induced mitotic catastrophe, and against apoptosis induced by tumor necrosis factor related apoptosis inducing ligand (TRAIL), suggesting selectivity in its pro-survival activity. CONCLUSION: These results underscore the ability of docetaxel to induce concomitantly caspase-dependent and independent death pathways in prostate cancer cells. The results also point to LEDGF/p75 as a potential contributor to cellular resistance to docetaxel-induced lysosomal destabilization and cell death, and an attractive candidate for molecular targeting in HRPC.

Activation and reversal of lipotoxicity in PC12 and rat cortical cells following exposure to palmitic acid.

Lipotoxicity involves a series of pathological cellular responses after exposure to elevated levels of fatty acids. This process may be detrimental to normal cellular homeostasis and cell viability. The present study shows that nerve growth factor-differentiated PC12 cells (NGFDPC12) and rat cortical cells (RCC) exposed to high levels of palmitic acid (PA) exhibit significant lipotoxicity and death linked to an "augmented state of cellular oxidative stress" (ASCOS). The ASCOS response includes generation of reactive oxygen species (ROS), alterations in the mitochondrial transmembrane potential, and increase in the mRNA levels of key cell death/survival regulatory genes. The observed cell death was apoptotic based on nuclear morphology, caspase-3 activation, and cleavage of lamin B and PARP. Quantitative real-time PCR measurements showed that cells undergoing lipotoxicity exhibited an increase in the expression of the mRNAs encoding the cell death-associated proteins BNIP3 and FAS receptor. Cotreatment of NGFDPC12 and RCC cells undergoing lipotoxicity with docosahexaenoic acid (DHA) and bovine serum albumin (BSA) significantly reduced cell death within the first 2 hr following the initial exposure to PA. The data suggest that lipotoxicity in NGFDPC12 and cortical neurons triggers a strong cell death apoptotic response. Results with NGFDPC12 cells suggest a linkage between induction of ASCOS and the apoptotic process and exhibit a temporal window that is sensitive to DHA and BSA interventions.

Alternative splicing and caspase-mediated cleavage generate antagonistic variants of the stress oncoprotein LEDGF/p75.

There is increasing evidence that an augmented state of cellular oxidative stress modulates the expression of stress genes implicated in diseases associated with health disparities such as certain cancers and diabetes. Lens epithelium-derived growth factor p75 (LEDGF/p75), also known as DFS70 autoantigen, is emerging as a survival oncoprotein that promotes resistance to oxidative stress-induced cell death and chemotherapy. We previously showed that LEDGF/p75 is targeted by autoantibodies in prostate cancer patients and is overexpressed in prostate tumors, and that its stress survival activity is abrogated during apoptosis. LEDGF/p75 has a COOH-terminally truncated splice variant, p52, whose role in stress survival and apoptosis has not been thoroughly investigated. We observed unbalanced expression of these proteins in a panel of tumor cell lines, with LEDGF/p75 generally expressed at higher levels. During apoptosis, caspase-3 cleaved p52 to generate a p38 fragment that lacked the NH(2)-terminal PWWP domain and failed to transactivate the Hsp27 promoter in reporter assays. However, p38 retained chromatin association properties and repressed the transactivation potential of LEDGF/p75. Overexpression of p52 or its variants with truncated PWWP domains in several tumor cell lines induced apoptosis, an activity that was linked to the presence of an intron-derived COOH-terminal sequence. These results implicate the PWWP domain of p52 in transcription function but not in chromatin association and proapoptotic activities. Consistent with their unbalanced expression in tumor cells, LEDGF/p75 and p52 seem to play antagonistic roles in the cellular stress response and could serve as targets for novel antitumor therapies.

Involvement of lysosomal cathepsins in the cleavage of DNA topoisomerase I during necrotic cell death.

OBJECTIVE: Autoantibodies to DNA topoisomerase I (topo I) are associated with diffuse systemic sclerosis (SSc), appear to be antigen driven, and may be triggered by cryptic epitopes exposed during in vivo topo I fragmentation. These autoantibodies recognize topo I and fragments of this autoantigen generated during apoptosis and necrosis. We undertook this study to determine whether lysosomal cathepsins are involved in topo I fragmentation during necrosis. METHODS: Topo I cleavage during necrosis was assessed by immunoblotting of lysates from L929 fibroblasts exposed to tumor necrosis factor alpha (TNFalpha) and the broad caspase inhibitor Z-VAD-FMK, and by immunoblotting of lysates from endothelial cells treated with HgCl2. Purified topo I and L929 nuclei were incubated with cathepsins B, D, G, H, and L, and topo I cleavage was detected by immunoblotting. The intracellular localization of cathepsin L activity and topo I in necrotic cells was examined using fluorescence microscopy. RESULTS: Treatment of L929 cells with TNFalpha and Z-VAD-FMK induced caspase-independent cell death with necrotic morphology. This cell death involved topo I cleavage into fragments of approximately 70 kd and 45 kd. This cleavage profile was reproduced in vitro by cathepsins L and H and was inhibited by the cathepsin L inhibitor Z-FY-CHO. During necrosis, cathepsin L activity diffused from lysosomes into the cytoplasm and nucleus, whereas topo I partially relocalized to the cytoplasm. Z-FY-CHO delayed necrosis and partially blocked topo I cleavage. The topo I cleavage fragments were also detected in necrotic endothelial cells and recognized by SSc sera containing anti-topo I antibodies. CONCLUSION: These results implicate cathepsins, particularly cathepsin L, in the cleavage of topo I during necrosis. This cleavage may generate potentially immunogenic fragments that could trigger anti-topo I immune responses in SSc.