An Interferon-Driven Oxysterol-Based Defense against Tumor-Derived Extracellular Vesicles

Tumor-derived extracellular vesicles (TEV) "educate" healthy cells to promote metastases. We found that melanoma TEV downregulated type I interferon (IFN) receptor and expression of IFN-inducible cholesterol 25-hydroxylase (CH25H). CH25H produces 25-hydroxycholesterol, which inhibited TEV uptake. Low CH25H levels in leukocytes from melanoma patients correlated with poor prognosis. Mice incapable of downregulating the IFN receptor and Ch25h were resistant to TEV uptake, TEV-induced pre-metastatic niche, and melanoma lung metastases; however, ablation of Ch25h reversed these phenotypes. An anti-hypertensive drug, reserpine, suppressed TEV uptake and disrupted TEV-induced formation of the pre-metastatic niche and melanoma lung metastases. These results suggest the importance of CH25H in defense against education of normal cells by TEV and argue for the use of reserpine in adjuvant melanoma therapy.

Function and regulation of the Caenorhabditis elegans Rab32 family member GLO-1 in lysosome-related organelle biogenesis

Cell type-specific modifications of conventional endosomal trafficking pathways lead to the formation of lysosome-related organelles (LROs). C. elegans gut granules are intestinally restricted LROs that coexist with conventional degradative lysosomes. The formation of gut granules requires the Rab32 family member GLO-1. We show that the loss of glo-1 leads to the mistrafficking of gut granule proteins but does not significantly alter conventional endolysosome biogenesis. GLO-3 directly binds to CCZ-1 and they both function to promote the gut granule association of GLO-1, strongly suggesting that together, GLO-3 and CCZ-1 activate GLO-1. We found that a point mutation in GLO-1 predicted to spontaneously activate, and function independently of it guanine nucleotide exchange factor (GEF), localizes to gut granules and partially restores gut granule protein localization in ccz-1(-) and glo-3(-) mutants. CCZ-1 forms a heterodimeric complex with SAND-1(MON1), which does not function in gut granule formation, to activate RAB-7 in trafficking pathways to conventional lysosomes. Therefore, our data suggest a model whereby the function of a Rab GEF can be altered by subunit exchange. glo-3(-) mutants, which retain low levels of GLO-3 activity, generate gut granules that lack GLO-1 and improperly accumulate RAB-7 in a SAND-1 dependent process. We show that GLO-1 and GLO-3 restrict the distribution of RAB-7 to conventional endolysosomes, providing insights into the segregation of pathways leading to conventional lysosomes and LROs.

Identification of factors associated with treatment refractoriness of oral lesions in pemphigus vulgaris

BACKGROUND

The oral mucosal lesions of patients with pemphigus vulgaris are known to show more treatment refractoriness than skin lesions.

OBJECTIVES

To identify which clinical and laboratory parameters may indicate treatment refractoriness of oral lesions in pemphigus vulgaris.

METHODS

This was a prospective study of 50 adults with pemphigus vulgaris and oral lesions; patients were given treatment appropriate for overall disease severity. Treatment refractoriness was defined arbitrarily as less than 75% reduction in oral objective Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) after treatment for 6 months.

RESULTS

Of 46 patients who completed the study, 17 (37%) were treatment refractory whereas 29 (63%) were treatment responsive. At baseline, the treatment refractory group had a significantly longer mean duration of disease (P = 0·02) and mean duration of oral lesions (P = 0·01), a higher percentage of lesions in the retromolar trigone (P = 0·05) and on the occlusion line along the buccal mucosa (P = 0·04), a higher percentage of deep/crateriform ulcers (P < 0·001) and erosions with a lichenoid hue (P < 0·001). Herpes simplex virus (HSV) DNA positivity, assessed by polymerase chain reaction in oral tissue scrapings (P = 0·02), was also significantly higher in the treatment refractory group. No other factors we tested for were statistically significant.

CONCLUSIONS

Treatment refractoriness of oral lesions was significantly associated with duration of disease/oral lesions; specific morphology and location of oral lesions; and the presence of HSV DNA in the oral cavity. These factors may forewarn the treating physician about a refractory course of oral lesions that may help with counselling patients.

Correlation between salivary and serum anti-desmoglein 1 and 3 antibody titres using ELISA and between anti-desmoglein levels and disease severity in pemphigus vulgaris

ELISA for anti-desmoglein antibodies (Dsg) is commonly used for diagnosis and assessment of treatment response in pemphigus vulgaris (PV). The present study was conducted to assess the relationship between salivary and serum Dsg1 and Dsg3 levels, and whether salivary Dsg1 and Dsg3 levels correlate with clinical disease severity of oral mucosal lesions in PV. In total 43, patients with PV with predominantly mucosal involvement were recruited. Both serum and salivary samples were collected from the cases, and salivary samples were also collected from five controls. There was a statistically significant correlation between serum and salivary Dsg1 levels and between serum and salivary Dsg3 levels. There was no correlation between serum or salivary Dsg1 and Dsg3 levels with the objective component of the oral mucosal Autoimmune Bullous Skin Disorder Intensity Score (ABSIS). Serum Dsg1 levels significantly correlated with cutaneous ABSIS, but there was no correlation between cutaneous ABSIS and either salivary Dsg1, salivary Dsg3 or serum Dsg3. As salivary Dsg titres correlate with serum levels, saliva can serve as a simple and noninvasive alternative to serum for Dsg ELISA.