Lyn Delivers Bacteria to Lysosomes for Eradication through TLR2-Initiated Autophagy Related Phagocytosis.

Extracellular bacteria, such as Pseudomonas aeruginosa and Klebsiella pneumoniae, have been reported to induce autophagy; however, the role and machinery of infection-induced autophagy remain elusive. We show that the pleiotropic Src kinase Lyn mediates phagocytosis and autophagosome maturation in alveolar macrophages (AM), which facilitates eventual bacterial eradication. We report that Lyn is required for bacterial infection-induced recruitment of autophagic components to pathogen-containing phagosomes. When we blocked autophagy with 3-methyladenine (3-MA) or by depleting Lyn, we observed less phagocytosis and subsequent bacterial clearance by AM. Both morphological and biological evidence demonstrated that Lyn delivered bacteria to lysosomes through xenophagy. TLR2 initiated the phagocytic process and activated Lyn following infection. Cytoskeletal trafficking proteins, such as Rab5 and Rab7, critically facilitated early phagosome formation, autophagosome maturation, and eventual autophagy-mediated bacterial degradation. These findings reveal that Lyn, TLR2 and Rab modulate autophagy related phagocytosis and augment bactericidal activity, which may offer insight into novel therapeutic strategies to control lung infection.

Annexin A2 Regulates Autophagy in Pseudomonas aeruginosa Infection through the Akt1-mTOR-ULK1/2 Signaling Pathway.

Earlier studies reported that a cell membrane protein, Annexin A2 (AnxA2), plays multiple roles in the development, invasion, and metastasis of cancer. Recent studies demonstrated that AnxA2 also functions in immunity against infection, but the underlying mechanism remains largely elusive. Using a mouse infection model, we reveal a crucial role for AnxA2 in host defense against Pseudomonas aeruginosa, as anxa2(-/-) mice manifested severe lung injury, systemic dissemination, and increased mortality compared with wild-type littermates. In addition, anxa2(-/-) mice exhibited elevated inflammatory cytokines (TNF-α, IL-6, IL-1ß, and IFN-γ), decreased bacterial clearance by macrophages, and increased superoxide release in the lung. We further identified an unexpected molecular interaction between AnxA2 and Fam13A, which activated Rho GTPase. P. aeruginosa infection induced autophagosome formation by inhibiting Akt1 and mTOR. Our results indicate that AnxA2 regulates autophagy, thereby contributing to host immunity against bacteria through the Akt1-mTOR-ULK1/2 signaling pathway.

Inhibition of p-IκBα Ubiquitylation by Autophagy-Related Gene 7 to Regulate Inflammatory Responses to Bacterial Infection.

BACKGROUND: Klebsiella pneumoniae causes serious infections and healthcare burdens in humans. We have previously reported that the deficiency of autophagy-related gene (Atg) 7 in macrophages (murine alveolar macrophage cell line [MH-S]) induced irregular host immunity against K. pneumoniae and worsened pathologic effects in the lung. In the current study, we investigated the molecular mechanism by which Atg7 influenced K. pneumoniae-induced inflammatory responses. METHODS: Expression levels of Atg7, ubiquitin (Ub), and tumor necrosis factor (TNF) α and phosphorylation of IκBα (p-IκBα) were determined with immunoblotting. Ubiquitylation of p-IκBα was determined with immunoprecipitation. RESULTS: We noted an interaction between Atg7 and p-IκBα, which was decreased in MH-S after K. pneumoniae infection, whereas the interaction between Ub and p-IκBα was increased. Knock-down of Atg7 with small interfering RNA increased p-IκBα ubiquitylation, promoted nuclear factor κB translocation into the nucleus, and increased the production of TNF-α. Moreover, knock-down of Ub with lentivirus-short hairpin RNA Ub particles decreased binding of p-IκBα to Ub and inhibited TNF-α expression in the primary alveolar macrophages and lung tissue of atg7-knockout mice on K. pneumoniae infection. CONCLUSIONS: Loss of Atg7 switched binding of p-IκBα from Atg7 to Ub, resulting in increased ubiquitylation of p-IκBα and intensified inflammatory responses against K. pneumoniae. Our findings not only reveal a regulatory role of Atg7 in ubiquitylation of p-IκBα but also indicate potential therapeutic targets for K. pneumoniae control.

MELD-Na > 16 is associated with high peri-procedural and short-term mortality in patients with ruptured hepatocellular carcinoma treated with emergent transarterial embolization.

PURPOSE: To evaluate prognostic factors associated with peri-procedural (30 days) and short-term (90 days) mortality in the United States cohort of patients following emergent transarterial embolization for ruptured hepatocellular carcinoma. METHODS: Patients with ruptured hepatocellular carcinoma treated with emergent TAE between January 2001 and December 2019 were retrospectively identified (n = 24). Average age was 62 years (range, 23-78 year); 15 (62.5%) were men. Univariate and Cox proportional hazard modeling were used to determine independent predictors of overall survival (OS) following TAE. OS stratified by Model for End-Stage Liver Disease-Sodium score was assessed using Kaplan-Meier analysis. RESULTS: Twenty-one patients (88%) died during a mean clinical follow-up period of 328 ± 139 days. MELD-Na score (HR 1.22 per 1-unit increase; 95% CI 1.06-1.46; p = 0.005) and pre-rupture ECOG PS score (HR 8.1; 95% CI 1.28-51.2; p = 0.026) were independent predictors of decreased overall survival. There was no significant association between overall survival and presence of cardiovascular co-morbidities (p = 0.60), hemorrhagic shock on presentation (p = 0.16), portal vein thrombus (p = 0.08), vasopressor support required (p = 0.79), intubation required (p = 0.40), acute kidney injury (p = 0.58), and number of packed red blood cell transfusions (p = 0.22). The median OS was 64 days. Median OS was significantly greater in patients with a MELD-Na score ≤ 16 as compared to those with a MELD-Na score > 16 (166.5 days vs 9 days, p = 0.011). Cumulative OS rates in those with a MELD-Na score ≤ 16 at 30, 60, 90, and 360 days were 79%, 64%, 64%, and 25%, respectively, vs 33%, 33%, 11%, and 0%, respectively, in those with a MELD-Na score > 16. CONCLUSION: MELD-Na > 16 is associated with very high peri-procedural (67% at 30 days) and short-term (89% at 90 days) mortality in patients with ruptured HCC treated with emergent transarterial embolization. A better understanding of these prognostic factors may help guide treatment decisions and provide realistic expectations when counseling patients and their families.

Restenosis Rates After Drug-Eluting Stent Treatment for Stenotic Small-Diameter Renal Arteries.

PURPOSE: To determine primary rates in small-diameter renal arteries, including complex bifurcation lesions, treated with drug-eluting stents (DES) in patients with atherosclerotic renal artery stenosis. MATERIALS AND METHODS: This is a retrospective single-institution study. A total of 37 patients with 39 stented renal arteries were included. Patient and procedural data were obtained from the electronic medical record. Survival free from restenosis was estimated using the Kaplan-Meier method with patients stratified into two groups based on renal artery diameters (≤ 3.5 mm or > 3.5 mm). Univariate Cox proportional models were used to estimate hazard ratios associated with clinical and angiographic variables. RESULTS: Average renal artery diameter at time of treatment was 3.4 mm ± 0.4 mm. The median survival free from restenosis was 992 days, with 11 out of 37 (29.7%) developing an in-stent restenosis. Renal arteries < 3.5 mm in diameter had similar patency rates as renal arteries > 3.5 mm (P = 0.33). The 1-, 2-, and 5-year patency rates were 71%, 63%, and 38%, respectively. History of stroke was the only comorbidity to portend a significantly greater rate of restenosis (hazard ratio 3.77; 95%CI, 1.05-13.6; P = 0.04). Medications did not statistically alter the risk of restenosis. CONCLUSION: Revascularization of renal arteries with DES achieved similar primary patency rates irrespective of renal artery diameter. Stent configuration was not associated with time to renal replacement therapy or all-cause mortality. LEVEL OF EVIDENCE: Level 3, Cohort Study.

Prostate cancer laparoscopic port site metastasis: A case report.

INTRODUCTION: Laparoscopic port site metastases are a rare but clinically important cause of biochemically recurrent prostate adenocarcinoma. C-11 choline, among other prostate-specific positron emission tomography (PET) radiotracers, has improved radiologist confidence in these otherwise difficult-to-detect sites of recurrence. PATIENT CONCERNS: A 62-year-old male presented with biochemically recurrent prostate adenocarcinoma after undergoing robotic-assisted radical prostatectomy 5 years earlier. DIAGNOSIS: C-11 choline positron emission tomography/computed tomography (PET/CT) demonstrated a choline-avid soft tissue nodule associated with a laparoscopic port site in the right rectus abdominis muscle, with correlative findings on prior magnetic resonance imaging, and biopsy confirming a prostate adenocarcinoma metastasis. INTERVENTIONS: The patient was initiated on chemohormonal therapy. OUTCOMES: His prostate-specific antigen (PSA) became undetectable following chemohormonal therapy. A follow-up C-11 choline PET/CT demonstrated complete resolution of prior abnormal radiotracer activity in the right rectus abdominis muscle. LESSONS: Port site metastases in prostate adenocarcinoma are rare; however, those who treat prostate cancer patients should be aware of this phenomenon as the number of minimally invasive oncologic procedures increase. C-11 choline PET, among other prostate-specific PET probes, has become an important tool in evaluating patients with biochemically recurrent prostate adenocarcinoma, identifying site-specific metastases in a majority of patients.

18F-FDG PET/CT Equivalent of the Hepatic Hot Spot Sign With CT Correlation.

A 43-year-old woman presented with an FDG-avid mediastinal Ewing sarcoma invading and nearly occluding the superior vena cava. Geographic increased FDG uptake in hepatic segment IVA was the only other site of nonphysiologic FDG activity. This focal activity was without an underlying mass, had atypical morphology for a hepatic metastasis, and correlated well with prior CT findings of abnormal segment IVA enhancement resulting from the recruitment of portocaval collaterals. In the correct setting, the F-FDG hepatic hot spot should be considered in the differential of a focal FDG-avid hepatic lesion in segment IVA.

Intravitreal bevacizumab and aflibercept for the treatment of exudative age-related macular degeneration.

BACKGROUND AND OBJECTIVE: To compare treatment of exudative age-related macular degeneration (AMD) with bevacizumab versus aflibercept in terms of central retinal thickness (CRT) and best corrected visual acuity (BCVA). PATIENTS AND METHODS: A retrospective cohort study examining changes in CRT and BCVA over 12 months of follow-up in 111 patients treated with bevacizumab and 91 treated with aflibercept for exudative AMD. RESULTS: Treatment with bevacizumab and aflibercept reduced CRT from baseline to 12 months. Aflibercept significantly reduced the mean change from baseline CRT at 12 months compared to bevacizumab. However, mean CRT at 12 months was not significantly different after aflibercept versus bevacizumab (271.6 ± 74.0 µm vs 257.9 ± 48.5 µm). BCVA was significantly better at 6 months in the aflibercept group. At baseline, 18.5% of bevacizumab and 26.4% of aflibercept patients had BCVA better than 20/40. At 12 months, 34.8% of bevacizumab and 38.9% of aflibercept patients had BCVA better than 20/40. CONCLUSION: CRT decreased and BCVA improved after treatment with bevacizumab and aflibercept for exudative AMD.