Betulinic acid induces a novel cell death pathway that depends on cardiolipin modification.

Cancer is associated with strong changes in lipid metabolism. For instance, normal cells take up fatty acids (FAs) from the circulation, while tumour cells generate their own and become dependent on de novo FA synthesis, which could provide a vulnerability to target tumour cells. Betulinic acid (BetA) is a natural compound that selectively kills tumour cells through an ill-defined mechanism that is independent of BAX and BAK, but depends on mitochondrial permeability transition-pore opening. Here we unravel this pathway and show that BetA inhibits the activity of steroyl-CoA-desaturase (SCD-1). This enzyme is overexpressed in tumour cells and critically important for cells that utilize de novo FA synthesis as it converts newly synthesized saturated FAs to unsaturated FAs. Intriguingly, we find that inhibition of SCD-1 by BetA or, alternatively, with a specific SCD-1 inhibitor directly and rapidly impacts on the saturation level of cardiolipin (CL), a mitochondrial lipid that has important structural and metabolic functions and at the same time regulates mitochondria-dependent cell death. As a result of the enhanced CL saturation mitochondria of cancer cells, but not normal cells that do not depend on de novo FA synthesis, undergo ultrastructural changes, release cytochrome c and quickly induce cell death. Importantly, addition of unsaturated FAs circumvented the need for SCD-1 activity and thereby prevented BetA-induced CL saturation and subsequent cytotoxicity, supporting the importance of this novel pathway in the cytotoxicity induced by BetA.

Lichen planus is associated with human herpesvirus type 7 replication and infiltration of plasmacytoid dendritic cells.

BACKGROUND: Lichen planus (LP) is a common inflammatory skin disease of unknown aetiology. Viral causes have been suggested. OBJECTIVES: To find candidate viruses associated with LP. METHODS: Lesional and nonlesional skin samples, peripheral blood mononuclear cells and serum were obtained from patients with LP. Ultrastructural, viral DNA, immunohistochemical and serological analyses were performed, and comparisons were made with psoriatic and normal skin. RESULTS: Electron microscopy revealed typical 120-200-nm enveloped particles with a 100-nm nucleus resembling human herpesvirus (HHV) virions both in dermis and in epidermis of lesional LP tissue. HHV-7 DNA was found in 11 of 18 lesional LP samples, as opposed to only one of 11 nonlesional LP samples (P =0.06), two of 11 lesional psoriasis samples (P = 0.05) and none of four normal skin samples. No relation was found between LP skin and DNA of other known HHVs (HHV-1-6 and 8). With immunohistochemistry, significantly more HHV-7+ cells were found in lesional LP epidermis than in normal epidermis. Lesional LP dermis contained significantly more HHV-7+ cells than nonlesional LP, psoriatic or normal dermis. Moreover, LP skin contained overwhelmingly and consistently more plasmacytoid dendritic cells (upregulated in virally induced conditions) than nonlesional LP samples. CONCLUSIONS: We conclude that HHV-7 replicates in LP lesions, but not in psoriasis, another inflammatory skin condition. HHV-7 is possibly involved in the pathogenesis of LP. These preliminary data make further research on this topic of interest.

Early effects of tumour necrosis factor alpha blockade on skin and synovial tissue in patients with active psoriasis and psoriatic arthritis.

BACKGROUND: Tumour necrosis factor alpha (TNFalpha) blockade using infliximab, a chimeric anti-TNFalpha antibody, is an effective treatment for both psoriasis and psoriatic arthritis (PsA). OBJECTIVE: To analyse the early effects of infliximab treatment on serial skin and synovial tissue biopsy samples. METHODS: Twelve patients with both active psoriasis and PsA received a single infusion of either infliximab (3 mg/kg) (n = 6) or placebo (n = 6) intravenously. Synovial tissue and lesional skin biopsy specimens were obtained at baseline and 48 hours after treatment. Immunohistochemical analysis was performed to analyse the inflammatory infiltrate. In situ detection of apoptotic cells was performed by TUNEL assay and by immunohistochemical staining with anti-caspase-3 antibodies. Stained tissue sections were evaluated by digital image analysis. RESULTS: A significant reduction in mean (SEM) T cell numbers was found in both lesional epidermis (baseline 37 (11) cells/mm, 48 hours 26 (11), p = 0.028) and synovial tissue (67 (56) cells/mm(2)v 32 (30), p = 0.043) after infliximab treatment, but not after placebo treatment (epidermis 18 (8) v 43 (20), NS; synovium 110 (62) v 46 (21), NS). Similarly, the number of macrophages in the synovial sublining was significantly reduced after anti-TNFalpha treatment (100 (73) v 10 (8), p = 0.043). The changes in cell numbers could not be explained by induction of apoptosis at the site of inflammation. CONCLUSIONS: The effects of anti-TNFalpha therapy in psoriasis and psoriatic arthritis may be explained by decreased cell infiltration in lesional skin and inflamed synovial tissue early after initiation of treatment.

[Reaction of the complement fixation test on microtitration plates: application to the serology of myxomatosis. Comparative study of the results with the reaction of indirect immunofluorescence]. / Réaction de fixation du complément en plaques de microtitration: application à la sérologie de la myxomatose. Etude comparative des résultats avec la réaction d'immunofluorescence indirecte.

The authors describe a complement fixation technique on microtitration plates, using an antigen prepared from myxomas induced in rabbits. Compared with indirect immunofluorescence this technique was less cumbersome, more economical, easier to read and (as a conventional procedure) applicable in all laboratories. Results obtained with 165 serum samples tested by both methods showed good correlation and a specificity at least equal to that of indirect immunofluorescence. Taking into account its lower sensitivity, the positive threshold value for complement fixation under the described experimental conditions was a dilution of 1:4 (H50).

Detection of African swine fever virus by a biotinylated DNA probe: assay on cell cultures and field samples.

African swine fever virus was detected in various samples using a molecular hybridization technique. A fragment located in a constant area of the viral genome was biotin-labelled. This probe, when present at a concentration of 100 ng/ml of the hybridization solution, could detect 10 pg of target DNA immobilized on nitrocellulose with cellular DNA and RNA. The virus was evidenced after being passaged on monkey kidney cells, either 8 h post-inoculation (pi) if the multiplicity of infection (MOI) was at least 1 hemadsorbing unit (HAd) per cell, or 24 h later if the inoculum was diluted up to 10(-3) HAd per cell. When passaged on pig leukocytes with a MOI of 0.1 HAd per cell, the virus was evidenced 12 h pi, or 24 h pi with a MOI of 10(-2) HAd per cell. The probe did not hybridize with another DNA virus passaged on cells, neither did it react with non-infected blood or ham, but did so if African swine fever virus was resuspended with the samples. The spleen from uninfected pig and the lymph nodes from a pig which had died from hog cholera were found to be negative, whereas the spleen from a pig which had died of African swine fever was positive. These samples were also tested with a 32P-labelled probe whose sensitivity was 10-fold higher. A non-radioactive probe could be used both for the sensitive and specific diagnosis of African swine fever and the detection of the virus in an epidemiological survey.

[A serological study of the contagious equine metritis: comparison between indirect immunofluorescence, slow agglutination and complement fixation techniques (author's transl)]. / Sérologie de la métrite contagieuse de la jument: comparaison des réactions d'immunofluorescence indirecte, de séroagglutination lente et de fixation du complément.

Serological response of pony mares to contagious equine metritis is studied comparing three techniques: slow agglutination, complement fixation and indirect immunofluorescence. Sera were taken from pony mares vaccinated with a heat inactivated suspension of Haemophilus equigenitalis, from experimentally-infected pony mares and from healthy horses. All three reactions detected antibodies in vaccinated and infected animals. The highest titers are observed with vaccinated mares. Titers are low in infected animals. Antibodies detected by indirect immunofluorescence appeared sooner and persisted longer in diseased animals than agglutinating or complement fixing antibodies. Only indirect immunofluorescence revealed a new contamination of two mares following coitus with a stallion excreting H. equigenitalis. Indirect immunofluorescence must be recommended in diagnosis of contagious equine metritis and in detection of chronic carriers.