Background

The association of alcohol with psoriasis has been inconsistent among studies.

Objectives

We aimed (1) to determine whether alcohol consumption (by status, frequency, and subtype of alcohol) modulates smoking-related psoriasis risk in postmenopausal women while stratifying for smoking status and pack-years and (2) to evaluate the effect of smoking cessation on psoriasis risk in postmenopausal women.

Methods

This prospective cohort study included 106,844 postmenopausal women enrolled in the Women's Health Initiative between 1993 and 1998. Patients diagnosed with psoriasis were identified using fee-for-service Medicare International Classification of Diseases, Ninth Revision, Clinical Modification codes assigned by dermatologists or rheumatologists. Self-administered questionnaires were used to obtain information on demographics, medical history, and smoking and alcohol habits. Hazard ratios from Cox regression models were adjusted for ethnicity, income, body mass index, and history of non-melanoma skin cancer and were stratified on age and on randomization status in the Women's Health Initiative study components.

Results

In the initial statistical model, past and current alcohol drinkers had higher risks of psoriasis compared with never-drinkers (P-trend < 0.001). This association was not observed after adjusting for cigarette smoking (P-trend: 0.478). The effect of alcohol (by status, frequency, and alcohol subtype) isolated by stratifying the analysis by smoking status (i.e., among never smokers) showed no association with psoriasis. Smoking showed an increasing risk for psoriasis with greater pack-years compared with those who have never smoked (P-trend: < 0.001). Compared to smokers at baseline, past smokers had a lower risk of psoriasis across women who smoked 5-14 cigarettes per day (hazard ratio 0.67, 95% confidence interval 0.51-0.88) and across women who smoked for 5-24 years (hazard ratio 0.65, 95% confidence interval 0.46-0.90).

Conclusions

These findings indicate that alcohol consumption does not modulate smoking-related psoriasis risk. Cigarette smoking, but not alcohol consumption, is an independent risk factor for psoriasis in postmenopausal women. As greater pack-years was associated with a higher risk of psoriasis and smoking cessation was conversely associated with a lower risk of psoriasis for moderate smokers, a greater emphasis on smoking abstinence and cessation counseling may benefit patients who already have other risk factors for psoriasis.

Background

Skin and soft tissue infections (SSTIs) are very common bacterial infections. There are few data on the microbiome of persons with and without SSTIs and the effects of systemic antibiotic therapy.

Methods

We sampled the skin microbiome from 10 outpatients with acute suppurative SSTI before and after systemic antibiotic therapy and enrolled 10 matched controls. Samples were collected at 6 skin body sites (occipital scalp, axilla, interdigital hand web spaces, gluteal crease, inguinal creases, and popliteal fossa), 2 mucosal sites (throat, anterior nares), and the site of skin infection (for case subjects) at baseline and a week later after abscess incision, drainage, and oral antibiotics.

Result

Among 10 SSTI cases, mean age was 41.5 years and 3 had diabetes mellitus. The gluteal crease at baseline had higher α-diversity in controls vs cases (P = .039); β-diversity analysis showed significant differences in overall bacterial community composition (P = .046). However, at other body sites there were no significant differences by either α- or β-diversity. Systemic antibiotic use did not affect body site diversity indices except at the SSTI site (α-diversity increased, P = .001).

Conclusions

We surprisingly found no significant differences in microbiome comparing noninfected skin sites before and after systemic SSTI antibiotic therapy nor significant differences at noninfected skin sites between SSTI cases and uninfected controls. We also found minimal significant differences between microbiome diversity and bacterial signatures at noninfected skin sites between patients with acute skin infection and uninfected controls. Our findings challenge the dogma that systemic antibiotics impact the skin microbiome.

Myristoylation is a type of protein acylation by which the fatty acid myristate is added to the N-terminus of target proteins, a process mediated by N-myristoyltransferases (NMT). Myristoylation is emerging as a promising cancer therapeutic target; however, the molecular determinants of sensitivity to NMT inhibition or the mechanism by which it induces cancer cell death are not completely understood. We report that NMTs are a novel therapeutic target in lung carcinoma cells with LKB1 and/or KEAP1 mutations in a KRAS-mutant background. Inhibition of myristoylation decreases cell viability in vitro and tumor growth in vivo. Inhibition of myristoylation causes mitochondrial ferrous iron overload, oxidative stress, elevated protein poly (ADP)-ribosylation, and death by parthanatos. Furthermore, NMT inhibitors sensitized lung carcinoma cells to platinum-based chemotherapy. Unexpectedly, the mitochondrial transporter translocase of inner mitochondrial membrane 17 homolog A (TIM17A) is a critical target of myristoylation inhibitors in these cells. TIM17A silencing recapitulated the effects of NMT inhibition at inducing mitochondrial ferrous iron overload and parthanatos. Furthermore, sensitivity of lung carcinoma cells to myristoylation inhibition correlated with their dependency on TIM17A. This study reveals the unexpected connection between protein myristoylation, the mitochondrial import machinery, and iron homeostasis. It also uncovers myristoylation inhibitors as novel inducers of parthanatos in cancer, and the novel axis NMT-TIM17A as a potential therapeutic target in highly aggressive lung carcinomas.

Significance

KRAS-mutant lung carcinomas with LKB1 and/or KEAP1 co-mutations have intrinsic therapeutic resistance. We show that these tumors are sensitive to NMT inhibitors, which slow tumor growth in vivo and sensitize cells to platinum-based chemotherapy in vitro. Inhibition of myristoylation causes death by parthanatos and thus has the potential to kill apoptosis and ferroptosis-resistant cancer cells. Our findings warrant investigation of NMT as a therapeutic target in highly aggressive lung carcinomas.