Genetic Obesity in Pregnant Ay Mice Does Not Affect Susceptibility to Obesity and Food Choice in Offspring

Maternal diet and obesity (MO) may influence taste preferences and increase the susceptibility to obesity in offspring, but the impact of MO per se to these influences is poorly understood. We evaluated the influence of MO on food choice and susceptibility to obesity in offspring when mothers consumed a standard diet (SD). Mice with the Lethal yellow mutation (Ay/a) develop obesity consuming an SD. Metabolic parameters were assessed in pregnant and lactating Ay/a (obesity) and a/a (control) mothers. Metabolic response to the consumption of a sweet–fat diet (SFD: SD, lard, and sweet biscuits) and the choice of components of this diet were evaluated in their male and female offspring. Compared to control mothers, pregnant obese mothers had higher levels of insulin, leptin, and FGF21. MO increased food intake and liver expression of lipogenesis genes in male offspring consuming the SD. SFD consumption caused obesity development and insulin resistance, increased liver expression of glycolytic and lipogenesis genes, and affected hypothalamic expression of anorexigenic and orexigenic genes. In offspring of both sexes, MO had no effect on food choice and metabolic response to SFD intake. Therefore, when obese mothers consume a balanced diet, MO does not affect food choice and development of diet-induced obesity in offspring.

Comprehensive study of health effects of plasma technology occupational environment: Exposure to high frequency and intensity noise and toxic gases

OBJECTIVES

To evaluate on animal models the health effects of the combined or separate exposure to main chemical and physical hazards of plasma-based material processing technology environment.

MATERIALS AND METHODS

Male Wistar rats were exposed to actual levels of hazardous factors in plasma technology occupational environment: i.e., ozone and nitrogen oxides (O₃ and NO_x) in respective concentrations of 0.5 mg/m³ and 1.0 mg/m³ and high-frequency (1000-1600 Hz) of 112 dB intensity noise for 3 h/day, 5 days/week for 12 weeks, with a recovery period of 1 month.

RESULTS

Exposure to noise or its combination with chemical factors (ozone, nitrogen oxides) causes non-specific CNS changes testifying for significant excitation dominance, especially in the case of joint exposure. Histological examination of rats' brain in experimental revealed a pronounced increase in blood filling of small vessels on the tenth day of the experiment, with subsequent intensification of vascular alterations and eventually to cerebral edema. The exposure to noise significantly reduced total thymus, bone marrow and spleen cell numbers and these was also more pronounced under the joint impact of noise and toxic gases. Thymus, but not bone marrow or spleen, mitotic activity was as well reduced under the same modes of exposure. Cytological investigation of film preparations of subcutaneous connective tissue revealed that joint exposure led to microcirculatory disorders, increased number of dark mast cells and reduced degranulation processes indicative of increased autoregulatory processes effective at microvasculature level.

CONCLUSIONS

High-frequency and intensity noise is main stressor factor that has negative impact on CNS and immune system, morphology and functioning of hematopoietic organs (spleen, bone marrow, thymus) and connective tissue. Its negative impact is significantly potentiated by concurrent exposure to ozone and nitrogen oxide, while exposure only to these toxic gases has no significant effect on the above targets.

Imbalance of Long-Chain Omega 3 Polyunsaturated Fatty Acids and Sterols in the Diet of Healthy Young People

Objectives

The present research was aimed at studying the content of lipid components with high biological activity in the diet of healthy young people, which regulate the risk of developing cardiovascular pathology. The purpose of this series of studies was the prevention of actual metabolic disorders as a result of changing the stereotypes choice food sources of the essential lipid components.

Methods

This study analyzed the diets of a representative group of students of the I.M.Sechenov First Moscow State Medical University: 77 men and 237 women aged 17–27. The 24 hour recall method was used three times and nutrient content was further assessed using a standard database.

Results

The average energy value was 1788 ± 428.6 kcal for men and 1618 ± 605 kcal for women. The percentage of energy from total fat was higher than the recommended one (more than 30% of fat calories from the total energy value of the diet): by 75% (84.2 ± 23.3 g) and 95.3% (70.5 ± 23.2 g) in men and women respectively. Of greatest interest was the analysis of the amount and ratio of essential polyunsaturated fatty acids (PUFAs) of the omega 6 and omega 3 groups, as well as sterols. While the ratio of linoleic acid/α-linolenic acid was the same (9/1) in both men and women, a significant difference was shown in their amount: linoleic acid/α-linolenic acid in men was estimated at 12 g/1.4 g and 9.7 g/1.2 g in women. The amount of essential fatty acids was 6.1% and 0.7% of the total calorie content of the diet. Consumption of long-chain omega 3 PUFAs was extremely low: 80.5 ± 53.5 mg and 209.4 ± 139.5 mg of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), respectively, in the men group; 79.2 ± 68.05 mg and 229.7 ± 180.2 mg in the women group. The intake of cholesterol and plant sterols, as well as their ratio, turned out to be suboptimal both in men 1.40/1 (455 ± 204.8 mg/357 ± 163.9 mg) and in women 1.38/1 (372.3 ± 168.3 mg/295.8 ± 150.8 mg).

Conclusions

 The results showed a significant imbalance of PUFAs and sterols in the students' diet. To optimize the fatty acid composition of the diet, on the one hand, it is necessary to reduce the proportion of total fat, and also include sources of long-chain omega 3 PUFAs (EPA and DHA) in the diet 2–3 times a week, primarily through oily (but not salty) marine fish, on the other hand, consume low-fat foods containing plant sterols such as cereals products and vegetables daily.

Funding Sources

No funding.

Consumption dietary sources of lycopene, lutein, and zeaxanthin among young adults living in megapolis

Carotenoids are natural antioxidants, affecting apoptosis, absorbing active forms of oxygen, and improving visual performance through their blue light filtering capabilities. Lutein and zeaxanthin are carotenoids of the macular pigment that play a significant role in protecting against age-related macular degeneration (AMD), cataracts, and diabetic retinopathy. We analyzed the dietary sources of lycopene, lutein, and zeaxanthin of young adults living in a megapolis. We analyzed 431 food frequency questionnaires and used two different criteria for comparison: age (groups A1 and A2) and season (groups S1, spring, and S2, autumn). Raw red tomatoes and eggs are the main sources of carotenoids for the majority of respondents regardless of age and season. Significant differences between age groups were found for parsley, carrot, cheeseburger, and spring onion. Foods with high levels of carotenoids (tomato juice, pumpkin, spinach, and sprouts) were absent in the diets of most of the study participants. Watermelons and persimmons are seasonal sources of lycopene, lutein, and zeaxanthin. Dietary sources of carotenoids are present in insufficient quantities in the diets. Foods with high levels of lycopene, lutein, and zeaxanthin are absent or only occasionally included in the diet.

Delayed diagnosis of tuberculosis in persons living with HIV in Eastern Europe: associated factors and effect on mortality-a multicentre prospective cohort study

BACKGROUND

Early diagnosis of tuberculosis (TB) is important to reduce transmission, morbidity and mortality in people living with HIV (PLWH).

METHODS

PLWH with a diagnosis of TB were enrolled from HIV and TB clinics in Eastern Europe and followed until 24 months. Delayed diagnosis was defined as duration of TB symptoms (cough, weight-loss or fever) for ≥ 1 month before TB diagnosis. Risk factors for delayed TB diagnosis were assessed using multivariable logistic regression. The effect of delayed diagnosis on mortality was assessed using Kaplan-Meier estimates and Cox models.

FINDINGS

480/740 patients (64.9%; 95% CI 61.3-68.3%) experienced a delayed diagnosis. Age ≥ 50 years (vs. < 50 years, aOR = 2.51; 1.18-5.32; p = 0.016), injecting drug use (IDU) (vs. non-IDU aOR = 1.66; 1.21-2.29; p = 0.002), being ART naïve (aOR = 1.77; 1.24-2.54; p = 0.002), disseminated TB (vs. pulmonary TB, aOR = 1.56, 1.10-2.19, p = 0.012), and presenting with weight loss (vs. no weight loss, aOR = 1.63; 1.18-2.24; p = 0.003) were associated with delayed diagnosis. PLWH with a delayed diagnosis were at 36% increased risk of death (hazard ratio = 1.36; 1.04-1.77; p = 0.023, adjusted hazard ratio 1.27; 0.95-1.70; p = 0.103).

CONCLUSION

Nearly two thirds of PLWH with TB in Eastern Europe had a delayed TB diagnosis, in particular those of older age, people who inject drugs, ART naïve, with disseminated disease, and presenting with weight loss. Patients with delayed TB diagnosis were subsequently at higher risk of death in unadjusted analysis. There is a need for optimisation of the current TB diagnostic cascade and HIV care in PLWH in Eastern Europe.

Phytosterols Deficiency in a Diet of Young People: Results of the Nutritional Assessment

Objectives

Phytosterols are important biologically active components of the human diet, preventing dyslipidemia, and atherosclerosis and reduce the risk of developing metabolic syndrome and cardiovascular pathologies. This study was designed with two aims: (a) To assess the level of phytosterols intake; (b) To describe which food sources make the largest contribution to phytosterols intake.

Methods

The level of consumed phytosterols and their main food sources were assessed using the 24-hour recall method using the database the national Institute of health and social security of Finland (Fineli). A survey was conducted among 125 students aged 17 to 29 years. The average age of students was 22.38 ± 1.73 years, and included 94 females and 31 males.

Results

None of the respondents reached the recommended phytosterols level (300 mg/day), although 97.6% of them included various sources of phytosterols in a diet. Only for 8.8% of participants intake of phytosterols was more than half the recommended level (153.54–249.96 mg/day). The main sources of phytosterols in this group were: onions – 72.7% of respondents included it's in their diet, sunflower oil and fresh tomatoes – 63.6%, potatoes – 54.5%, fresh cucumbers – 45.4%, apples and white cabbage 36.3%, tomato paste 27.2%, cauliflower, Chinese cabbage, parsley, beets – 18.8%, corn and olive oils, sauerkraut, broccoli, Brussels sprouts, beans, avocado, kiwi – 9.09%. For 88.8% of participants, dietary phytosterols intake was less than half the recommended level (2.13–146.39 mg/day). In this group, the main sources of phytosterols were: sunflower oil – 52.5%, potatoes – 46.8%, onions – 43.2%, fresh tomatoes – 36.9%, fresh cucumbers – 34.2%, fresh apples – 29.7%, bananas – 20.7%, white cabbage and sauerkraut – 17.1%, sweet red pepper – 13.5%, fresh and canned peas – 11.7%, parsley and dill – 10.8%, Chinese cabbage, beets and olive oil – 8.1%, oranges, green onions and beans – 5.4%. The students did not include phytosterols-rich foods in their diet: green grapes, black and red currants, blueberries, cranberries, and raspberries.

Conclusions

Obviously, in order to achieve the optimal level of phytosterols in the diet, it is not enough to use their sources with low and medium phytosterols content. It is necessary to include in the diet either foods enriched with them, or selectively foods with their high content.

Funding Sources

No funding.

POS1332 ETANERCEPT-ASSOCIATED NEW ONSET UVEITIS IN PATIENTS WITH JUVENILE IDIOPATHIC ARTHRITIS UNDER BIOLOGICAL THERAPY: SINGLE CENTER EXPERIENCE

Background:

Biological agents (BA), especially TNF inhibitors, are high efficacy options for current therapy for patients (pts) with juvenile idiopathic arthritis (JIA). They are successfully used not only for the arthritis but also for JIA-associated uveitis, however, development of uveitis de novo in pts treated with BA is a well-established paradoxical phenomenon.

Objectives:

to evaluate the frequency of new onset (no-) uveitis, occurring under BA therapy in JIA pts, to establish clinical features, which may be associated with development of such effects.

Methods:

retrospective cohort study involved all JIA pts (1136) who were treated with BA in our clinic from 2004 to 2020. All cases of no-uveitis were collected for the describing of their clinical features in disease onset and course, activity level, JIA category, exposure to Methotrexate (MTX) and BA, presence of ANA, HLA B27.

Results:

among of 1136 pts treated with different BA we identified 36 (3.3%) pts (19 female/17 male) with no-uveitis under BA. Mostly during etanercept (ETA) therapy (34 cases from 488 ETA courses, 7%), 1/166 - in abatacept (ABA) and 1/372 - in adalimumab (ADA). 30 pts (83%) with no-uveitis developed it on the 1st line of BA treatment (29 ETA vs 1 ADA). 4pts (11%) developed no-uveitis on 2 nd line (3 ETA vs 1 ABA). 2 pts (6%) on third line (all ETA, both pts had also psoriasis). There are no cases of no-uveitis under other BA. Frequency of no-uveitis was much higher in ETA group. ETA exposure was 26.8 ± 28.8 months (mo). It means there are no “safe” period of therapy from paradoxical phenomenon of no-uveitis. JIA subtypes were as follows: RF-neg polyarthritis 9 (25%), persistent oligoarthritis 3 (8%), extended oligoarthritis 21 (59%), enthesitis-related arthritis (ERA) - 3 (8%). Average age at JIA onset was 4.6 ± 3.9 yrs. 20/36 patients had high laboratory activity (CRP 54 ± 23 mg/l; ESR 41 ± 19 mm/h) and severe arthritis before BA initiation. However most of pts (25/36) achieved 90-100% ACRpedi-response by the uveitis development. 23/36 pts were ANA-positive, 17/36 pts had HLAB27, including 7 pts who had the both features. Uveitis was occurred earlier in ANA plus HLAB27 positive pts (mean exposure - 15.3 mo) than in only ANA-positive or HLAB27-positive pts (27.7 mo and 27.6 mo accordingly). 29/36 (81%) of pts received methotrexate (MTX) in mean dosage 11.5 mg/m2/week. There are no differences in time of uveitis development depending of MTX. In all cases of no-uveitis BA was switched.

Conclusion:

Our study suggested that new onset of uveitis is rare adverse event during BA therapy in JIA. Uveitis can develop despite the excellent effect of therapy on joint manifestation. The most typical development of no-uveitis is under ETA therapy, especially in the predisposed cases (certain variants of JIA, ANF positivity, HLAB27 presence) and in patients with very high disease activity at the time of the start of biological therapy.

Disclosure of Interests:

Irina Nikishina Speakers bureau: Novartis, MSD, Pfizer, Abbvie, Hofman la Roche, Svetlana Arsenyeva: None declared, Maria Kaleda Speakers bureau: Novartis, Roche, MSD, Olga Kostareva: None declared, Anna Shapovalenko: None declared, Ekaterina Denisova: None declared, Anna Panova: None declared

Healthcare delivery for HIV-positive people with tuberculosis in Europe

BACKGROUND

In a 2013 survey, we reported distinct discrepancies in delivery of tuberculosis (TB) and HIV services in eastern Europe (EE) vs. western Europe (WE).

OBJECTIVES

To verify the differences in TB and HIV services in EE vs. WE.

METHODS

Twenty-three sites completed a survey in 2018 (EE, 14; WE, nine; 88% response rate). Results were compared across as well as within the two regions. When possible, results were compared with the 2013 survey.

RESULTS

Delivery of healthcare was significantly less integrated in EE: provision of TB and HIV services at one site (36% in EE vs. 89% in WE; P = 0.034), and continued TB follow-up in one location (42% vs. 100%; P = 0.007). Although access to TB diagnostics, standard TB and HIV drugs was generally good, fewer sites in EE reported unlimited access to rifabutin/multi-drug-resistant TB (MDR-TB) drugs, HIV integrase inhibitors and opioid substitution therapy (OST). Compared with 2013, routine usage of GeneXpert was more common in EE in 2018 (54% vs. 92%; P = 0.073), as was access to moxifloxacin (46% vs. 91%; P = 0.033), linezolid (31% vs. 64%; P = 0.217), and bedaquiline (0% vs. 25%; P = 0.217). Integration of TB and HIV services (46% vs. 39%; P = 1.000) and provision of OST to patients with opioid dependency (54% vs. 46%; P = 0.695) remained unchanged.

CONCLUSION

Delivery of TB and HIV healthcare, including integration of TB and HIV care and access to MDR-TB drugs, still differs between WE and EE, as well as between individual EE sites.

Lycopene Quantity and Sources in the Diet of Healthy Young People

Objectives

Lycopene is a major dietary non-vitamin carotenoid, which has a high number of conjugated dienes, and known as a powerful antioxidant and radical scavenger. The present study was designed to assess the level of lycopene intake and to describe which food sources contribute the most to intake.

Methods

Lycopene's level and its main food sources were assessed using the 24-hour reсall method. Periodicity of intake food sources were assessed using a specialized Food Frequency Questionnaire applying the carotenoids database from the USDA. A survey was conducted among 122 students in age group 20 to 28 years (21.86 ± 1.12) and included 89 females and 33 males.

Results

Only 43.4% respondents have achieved the recommended level of lycopene (12.64 ± 8.57 mg/day). In this group the following sources of lycopene were presented: red raw tomatoes (47.2%), fast food products – pizza, lasagna, pasta (18.9%), ketchup (15.1%), watermelon (11.3%), tomato juice (5.6%), pink and red grapefruits (1.9%). For 14.7% students the intake of lycopene in the diet was more than half of the recommended level. The main sources of lycopene in this group were red raw tomatoes (61.1%), pizza, sandwiches (33.3%), and ketchup (5.6%). For 15.6% participants the dietary intake of lycopene was less than half of the recommended level. In this group, the major sources of lycopene were the following: ketchup (21.3%), soup and sandwiches (21.1% each), red raw tomatoes (15.8%), canned fish in tomato sauce (10.5%) and tomato juice (5.2%). A quarter of respondents had no sources of lycopene in their diet. An assessment of the results of survey of 122 students revealed that 91 respondents included red raw tomatoes in weekly diet (9.0% – 6–7 times a week, 47.6% – 3–5 times a week, 18.0% – 1–2 times a week). The weekly diet of more than a third of respondents contained tomato-based sources of lycopene: pizza (47.5%), ketchup (46.7%), cheeseburger (34.4%) and hamburger (17.2%). Thus, the significant number of study participants did not include tomato juice (55.7%), red tomatoes (49.1%), persimmon (45.9%), pink or red grapefruit (41.0%).

Conclusions

The recommended quantity of lycopene intake was achieved by including raw red tomatoes and tomato-containing products in the diet. Additional sources of lycopene (watermelon, red and pink grapefruits, persimmon) in the diet of most students were absent.

Funding Sources

No funding.

The Content of Lutein and Zeaxanthin in the Diet of Young Health People (P02-006-19)

Objectives

Lutein and zeaxanthin are non-vitamin carotenoids, which located in macula. These carotenoids reduce the risk of progression of age-related macular degeneration. The purpose of research to analyze the amount of lutein and zeaxanthin in diets of young health people and to asses food choices rich non-vitamin carotenoids.

Methods

Adults aged 20–25 y (n = 424, 113 males age 22.0 ± 0.9 y, 311 females age 22.0 ± 0.8 y). Lutein and zeaxanthin levels from food sources have been estimated using the 24-hour recall method. The questionnaire was designed specifically to conduct a specific study. It provided for the selection of food sources, and indication of the consumed amount of lutein and zeaxanthin.

Results

Of the 424 students only 24 (5.7%) have reached the recommended level (8.84 ± 3.39 mg/day). The main sources of lutein and zeaxanthin in this group were zucchini (29.2%); broccoli, lettuce, persimmon and spinach (12.5% each), pumpkin and parsley (8.3% each), peas (4.2%). The dietary intake of non-vitamin carotenoids for 41 students (9,7%) was 50.0–99.9% (4.19 ± 0.76 mg/day) of the recommended level. The student's diet of this group included sources of lutein and zeaxanthin such as lettuce (34.2%), broccoli (24.4%), zucchini (12.2%), corn and persimmon (7.3% each), pumpkin and spinach (4.9% each), orange juice and peas (2.4% each). Most of the study participants (306 students – 72.1%) had insufficient intake of lutein and zeaxanthin with food sources and was less than half of the recommended level (0.93 ± 0.82 mg/day). The major sources of non-vitamin carotenoids were eggs (22.9%); red raw tomatoes (15.0%); lettuce (11.1%); zucchini (7.2%); fast food products and orange juice (5.6% each); peas (4.9%); carrot (4.2%); ketchup (3.9%); parsley (3.6%); corn and persimmon (3.3% each); broccoli (2.3%); kiwi (1.6%); pumpkin (1.3%); basil, green onion, canned fish, celery, canned red tomatoes, tomato juice, pistachios and spinach (0.3–0.9%). Sources of lutein and zeaxanthin, such as Brussels sprouts, blackberries, blueberries, were not included in the diet. Moreover, 53 (12,5%) students had no sources of lutein and zeaxanthin in their diet.

Conclusions

For the most of students, the recommended intake of lutein and zeaxanthin was not achieved. The major food sources were included in the diet in insufficient quantities.

Funding Sources

No funding.

Compliance with follow-up (f.-up) program and outcome of patients (pts) with stage I nonseminomatous germ cell tumors (NSGCT)

e15025

Background: There are limited data about f.-up quality of pts with stage I NSGCT after orchiectomy (OE) management and their survival. A retrospective analysis was performed to find the impact of compliance with schedule of f.-up on outcome of relapsed pts with stage I NSGCT. Methods: We analyzed data of 261 pts with stage I GCT treated in our department from 1994 to 2010. NSGCT was revealed in 128 (49%) pts. Therapeutic options following OE comprised retroperitoneal lymph node dissection (RPLND) – in 4/128 (3%), adjuvant cisplatin-based chemotherapy (CT) - in 75/128 (58%) and surveillance - in 49/128 (39%). The following procedures were performed in our center during the f.-up: ultrasound of the abdomen and pelvis, serum AFP, HCG and LDH – bimonthly in the 1st year, quarterly in the 2nd year, biannually in the 3rd-4th years and then annually; X-Ray of the chest – thrice-yearly in the 1st year, biannually on the 2nd year and then annually. Median f.-up time was 75 (range 16 - 176) months. Results: No pts had relapse after RPLND, 4/75 (5,3%) pts had relapses after CT, 16/49 (32%) pts – in surveillance group. 17/20 (85%) relapses were revealed in the first 2 years of f.-up. During relapses, 17/20 (85%) pts had good, 2/20 (10%) - intermediate and 1 patient - poor IGCCCG prognosis. The mean number of visits in the 1st year after OE was 3, on the 2nd year -1,4, in the 3rd- 4th years - 1 per year. All relapsed pts received induction CT (EP or BEP regimen). 11/20 (55%) pts were compliant to visits, 9/20 (45%) pts were not. The 5-years overall survival was 90% and 68% (p=0,3); the median size of metastases in RPLN was 2,2 and 5,5 cm (p=0,001), respectively. All pts in intermediate and poor prognosis were in the noncompliant group, whereas all pts, who were compliant were in good prognosis (3/9 (33%) vs 0/11 (0%), p=0,07). Moreover, surgical removal of residual tumor after induction CT was more often performed in the noncompliant group (5/11 (33%) vs 5/9 (71%), р=0.6). Conclusions: Poor compliance with f.-up program in stage I NSGCT results to non significant worse long-term outcome. Also pts, who were compliant had significantly smaller size of metastases in retroperitoneal lymph nodes at relapse and had good IGCCCG prognosis in all case.

Selective membrane permeabilization by the rotavirus VP5* protein is abrogated by mutations in an internal hydrophobic domain

Rotavirus infectivity is dependent on the proteolytic cleavage of the VP4 spike protein into VP8* and VP5* proteins. Proteolytically activated virus, as well as expressed VP5*, permeabilizes membranes, suggesting that cleavage exposes a membrane-interactive domain of VP5* which effects rapid viral entry. The VP5* protein contains a single long hydrophobic domain (VP5*-HD, residues 385 to 404) at an internal site. In order to address the role of the VP5*-HD in permeabilizing cellular membranes, we analyzed the entry of o-nitrophenyl-beta-D-galactopyranoside (ONPG) into cells induced to express VP5* or mutated VP5* polypeptides. Following IPTG (isopropyl-beta-D-thiogalactopyranoside) induction, VP5* and VP5* truncations containing the VP5*-HD permeabilized cells to the entry and cleavage of ONPG, while VP8* and control proteins had no effect on cellular permeability. Expression of VP5* deletions containing residues 265 to 474 or 265 to 404 permeabilized cells; however, C-terminal truncations which remove the conserved GGA (residues 399 to 401) within the HD abolished membrane permeability. Site-directed mutagenesis of the VP5-HD further demonstrated a requirement for residues within the HD for VP5*-induced membrane permeability. Functional analysis of mutant VP5*s indicate that conserved glycines within the HD are required and suggest that a random coiled structure rather than the strictly hydrophobic character of the domain is required for permeability. Expressed VP5* did not alter bacterial growth kinetics or lyse bacteria following induction. Instead, VP5*-mediated size-selective membrane permeability, releasing 376-Da carboxyfluorescein but not 4-kDa fluorescein isothiocyanate-dextran from preloaded liposomes. These findings suggest that the fundamental role for VP5* in the rotavirus entry process may be to expose triple-layered particles to low [Ca](i), which uncoats the virus, rather than to effect the detergent-like lysis of early endosomal membranes.

Rotavirus capsid protein VP5* permeabilizes membranes

Proteolytic cleavage of the VP4 outer capsid spike protein into VP8* and VP5* proteins is required for rotavirus infectivity and for rotavirus-induced membrane permeability. In this study we addressed the function of the VP5* cleavage fragment in permeabilizing membranes. Expressed VP5* and truncated VP5* proteins were purified by nickel affinity chromatography and assayed for their ability to permeabilize large unilamellar vesicles (LUVs) preloaded with carboxyfluorescein (CF). VP5* and VP5* truncations, but not VP4 or VP8*, permeabilized LUVs as measured by fluorescence dequenching of released CF. Similar to virus-induced CF release, VP5*-induced CF release was concentration and temperature dependent, with a pH optimum of 7.35 at 37 degrees C, but independent of the presence of divalent cations or cholesterol. VP5*-induced permeability was completely inhibited by VP5*-specific neutralizing monoclonal antibodies (2G4, M2, or M7) which recognize conformational epitopes on VP5* but was not inhibited by VP8*-specific neutralizing antibodies. In addition, N-terminal and C-terminal VP5* truncations including residues 265 to 474 are capable of permeabilizing LUVs. These findings demonstrate that VP5* permeabilizes membranes in the absence of other rotavirus proteins and that membrane-permeabilizing VP5* truncations contain the putative fusion region within predicted virion surface domains. The ability of recombinant expressed VP5* to permeabilize membranes should permit us to functionally define requirements for VP5*-membrane interactions. These findings indicate that VP5* is a specific membrane-permeabilizing capsid protein which is likely to play a role in the cellular entry of rotaviruses.