Interaction of RIPK1 and A20 modulates MAPK signaling in murine acetaminophen toxicity.

Acetaminophen (APAP)-induced liver necrosis is a form of regulated cell death (RCD) in which APAP activates the mitogen-activated protein kinases (MAPKs) and specifically the c-Jun-N-terminal kinase (JNK) pathway, leading to necrotic cell death. Previously, we have shown that receptor interacting protein kinase-1 (RIPK1) knockdown is also protective against APAP RCD upstream of JNK. However, whether the kinase or platform function of RIPK1 is involved in APAP RCD is not known. To answer this question, we used genetic mouse models of targeted hepatocyte RIPK1 knockout (RIPK1HepCKO) or kinase dead knock-in (RIPK1D138N) and adult hepatocyte specific knockout of the cytoprotective protein A20 (A20HepCKO), known to interact with RIPK1, to study its potential involvement in MAPK signaling. We observed no difference in injury between WT and RIPK1D138N mice post APAP. However, RIPK1HepCKO was protective. We found that RIPK1HepCKO mice had attenuated pJNK activation, while A20 was simultaneously upregulated. Conversely, A20HepCKO markedly worsened liver injury from APAP. Mechanistically, we observed a significant upregulation of apoptosis signal-regulating kinase 1 (ASK1) and increased JNK activation in A20HepCKO mice compared with littermate controls. We also demonstrated that A20 coimmunoprecipitated (co-IP) with both RIPK1 and ASK1, and that in the presence of RIPK1, there was less A20-ASK1 association than in its absence. We conclude that the kinase-independent platform function of RIPK1 is involved in APAP toxicity. Adult RIPK1HepCKO mice are protected against APAP by upregulating A20 and attenuating JNK signaling through ASK1, conversely, A20HepCKO worsens injury from APAP.

Taxane-Induced Upper Gastrointestinal Bleeding.

Docetaxel is a taxane, which is a class of chemotherapy agent used in the treatment of multiple malignancies. It is known to have gastrointestinal side effects which can range from mild symptoms such as nausea and diarrhea to more severe complications such as neutropenic enterocolitis. In the current literature, taxanes have not been described to cause upper gastrointestinal bleeding and melena. Here, we present a case of a 54-year-old woman with breast cancer who developed dizziness, fatigue, and melena after receiving chemotherapy. Esophagogastroduodenoscopy revealed diffuse gastric erosions as well as ulceration and linear superficial lesions in the duodenum; biopsies from these sites showed taxane-induced toxicity. Her bleeding resolved with medical therapy and subsequent removal of docetaxel from her chemotherapy regimen. This case identifies upper gastrointestinal bleeding as a previously undescribed side effect of docetaxel therapy. Recent docetaxel use should be included in the differential diagnosis for upper gastrointestinal bleed, and diagnosis should lead to consideration of cessation of docetaxel or substitution with another chemotherapeutic agent.

The Prognostic Implications of Tumor Infiltrating Lymphocytes in Colorectal Cancer: A Systematic Review and Meta-Analysis.

Tumor-infiltrating lymphocytes (TILs) are an important histopathologic feature of colorectal cancer that confer prognostic information. Previous clinical and epidemiologic studies have found that the presence and quantification of tumor-infiltrating lymphocytes are significantly associated with disease-specific and overall survival in colorectal cancer. We performed a systematic review and meta-analysis, establishing pooled estimates for survival outcomes based on the presence of TILs in colon cancer. PubMed (Medline), Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov were searched from inception to April 2017. Studies were included, in which the prognostic significance of intratumoral tumor infiltrating lymphocytes, as well as subsets of CD3, CD8, FOXP3, CD45R0 lymphocytes, were determined within the solid tumor center, the invasive margin, and tumor stroma. Random-effects models were calculated to estimated summary effects using hazard ratios. Forty-three relevant studies describing 21,015 patients were included in our meta-analysis. The results demonstrate that high levels of generalized TILS as compared to low levels had an improved overall survival (OS) with a HR of 0.65 (p = <0.01). In addition, histologically localized CD3+ T-cells at the tumor center were significantly associated with better disease-free survival (HR = 0.46, 95% CI 0.36-0.61, p = 0.05), and CD3 + cells at the invasive margin were associated with improved disease-free survival (HR = 0.57, 95% CI 0.38-0.86, p = 0.05). CD8+ T-cells at the tumor center had statistically significant prognostic value on cancer-specific survival and overall survival with HRs of 0.65 (p = 0.02) and 0.71 (p < 0.01), respectively. Lastly, FOXP3+ T-cells at the tumor center were associated with improved prognosis for cancer-specific survival (HR = 0.65, p < 0.01) and overall survival (HR = 0.70, p < 0.01). These findings suggest that TILs and specific TIL subsets serve as prognostic biomarkers for colorectal cancer.

Sensitive CSF ELISAs for the detection of MBL, MASP-2 and functional MBL/MASP-2.

Mannose binding lectin (MBL) mediated complement pathway is an important constituent of innate immune response in several infections including neuroinflammatory and neurodegenerative diseases. Although there are Enzyme-Linked Immunosorbent Assays (ELISAs) for estimating MBL, MBL-associated serine protease-2 (MASP-2) and functional MBL-MASP-2 (fMBL) proteins for the plasma, serum and cell supernatants there are no established methods for their estimation in the cerebrospinal fluid (CSF). We developed sensitive ELISAs for the detection of MBL, fMBL and MASP-2 in the CSF. First, we adapted standard ELISAs for the detection of these proteins in the CSF. Second, we used a biotinyl-tyramide based horseradish peroxidase (HRP) signal amplification for the sensitive detection of these proteins in the CSF. In summary, using modified ELISA and biotinyl-tyramide based HRP signal amplification, we successfully detected MBL, fMBL and MASP-2 proteins in the CSF samples with high sensitivity and reproducibility.

Mannose binding lectin mediated complement pathway in multiple sclerosis.

Role of mannose binding lectin (MBL) complement activation pathway, an arm of innate immunity in multiple sclerosis (MS) was evaluated by analyzing the expression of MBL, MBL-associated serine protease-2 (MASP-2), and functional MBL/MASP-2 mediated C4 cleavage (fMBL) in 87 plasma and cerebrospinal fluid (CSF) samples from MS patients and non-MS controls. Median fMBL and MASP-2 plasma levels were higher in MS vs. non-MS cases. These associations remained in an analysis of subtypes of MS disease. These findings suggest a potential activation of MBL complement pathway in MS that may possibly alter the risk or progression of MS disease.