Elevated LDL-cholesterol (LDLc) levels are a major risk factor for cardiovascular disease and atherosclerosis. LDLc is cleared from circulation by the LDL receptor (LDLR). Proprotein convertase subtilisin/kexin 9 (PCSK9) enhances the degradation of the LDLR in endosomes/lysosomes, resulting in increased circulating LDLc. PCSK9 can also mediate the degradation of LDLR lacking its cytosolic tail, suggesting the presence of as yet undefined lysosomal-targeting factor(s). Herein, we confirm this, and also eliminate a role for the transmembrane-domain of the LDLR in mediating its PCSK9-induced internalization and degradation. Recent findings from our laboratory also suggest a role for PCSK9 in enhancing tumor metastasis. We show herein that while the LDLR is insensitive to PCSK9 in murine B16F1 melanoma cells, PCSK9 is able to induce degradation of the low density lipoprotein receptor-related protein 1 (LRP-1), suggesting distinct targeting mechanisms for these receptors. Furthermore, PCSK9 is still capable of acting upon the LDLR in CHO 13-5-1 cells lacking LRP-1. Conversely, PCSK9 also acts on LRP-1 in the absence of the LDLR in CHO-A7 cells, where re-introduction of the LDLR leads to reduced PCSK9-mediated degradation of LRP-1. Thus, while PCSK9 is capable of inducing degradation of LRP-1, the latter is not an essential factor for LDLR regulation, but the LDLR effectively competes with LRP-1 for PCSK9 activity. Identification of PCSK9 targets should allow a better understanding of the consequences of PCSK9 inhibition for lowering LDLc and tumor metastasis.

BACKGROUND: An elevated preoperative C-reactive protein/albumin (CRP/Alb) ratio has been reported to be associated with a poor prognosis for hepatocellular carcinoma. The aim of the present study was to investigate the prognostic value of the preoperative CRP/Alb ratio and compare it with other systemic inflammatory response markers in patients with gastric cancer (GC). METHODS: A retrospective study was performed in 455 patients with GC undergoing curative resection. We investigated the correlations between the preoperative CRP/Alb ratio and overall survival (OS). Kaplan-Meier and Cox regression models were used to assess independent prognostic factors. The area under the curve was used to compare the prognostic value of different markers. RESULTS: On multivariate analysis, the CRP/Alb ratio were independently associated with OS in patients with GC (hazard ratio: 1.626; 95% confidence interval: 1.191-2.219; P = .002), along with age (P = .003), preoperative body weight loss (P = .001), tumor location (P = .008), metastatic lymph node ratio (P < .001), and seventh tumor-nodes-metastasis stage (American Joint Committee on Cancer) (P = .007). However, several other systemic inflammation–based prognostic scores (neutrophil lymphocyte ratio, platelet lymphocyte ratio and systemic immune-inflammation index, Glasgow Prognostic Score, modified Glasgow prognostic score, and high-sensitivity modified Glasgow prognostic score) were not. In addition, the CRP/Alb ratio had a higher area under the curve value (0.625) compared with several other systemic inflammation–based prognostic scores (P < .001). CONCLUSION: The preoperative CRP/Alb ratio, a system inflammation-based prognostic score, is a superior predictor of OS in patients undergoing curative resection for GC and may help to identify the high-risk patients for treatment decisions.

Microglia activation is recognized as the hallmark of neuroinflammation. However, the activation profile and phenotype changes of microglia during the process of retinal degeneration are poorly understood. This study aimed to elucidate the time-spatial pattern of microglia distribution and characterize the polarized phenotype of activated microglia during retinal neuroinflammation and degeneration in rd1 (Pde6βrd1/rd1) mice, the classic model of inherited retinal degeneration. Retinae of rd1 mice at different postnatal days (P7, P14, P21, P28, P56, and P180) were prepared for further analysis. We found most CD11b+ or IBA1+ microglia expressed Ki-67 and CD68 in rd1 mice and these cells migrated toward the layer of degenerative photoreceptors at the rapid rods degeneration phase from P14 to P28. These microglia exhibited typical ameboid activated shape with round bodies and scarce dendrites, while at late phase at P180, they displayed resting ramified morphology with elongated dendrites. Flow cytometry revealed that the percentage of CD86+CD206- M1 microglia increased markedly in rd1 retinae, however, no significant change was observed in CD206+CD86- M2 microglia. Interestingly, CD86+CD206+ microglia, an intermediate state between the two extremes of M1 and M2, increased markedly at the rapid rods degeneration phase. The immunofluorescence images revealed that microglia in rd1 mice highly expressed M1 markers including CD16/32, CD86, and CD40. In addition, increased expression of pro-inflammatory cytokines (TNF-α, IL-6, and CCL2) was observed in rd1 mice. Our findings unfolded a panorama for the first time that microglia conducted distinctive behaviors with the progression of retinal degeneration in rd1 mice. Microglia is activated and particularly polarized to a pro-inflammatory M1 phenotype at the rapid rods degenerative phase, suggesting that the involvement of M1 microglia in the retinal neuroinflammation and degeneration. Most microglia adopted an intermediate polarization “M1½” state in rd1, revealing that microglia orchestrated a complicated continuous spectrum in degenerative retina.

Aims/hypothesis Increased inflammation and oxidative stress are associated with insulin resistance (IR) and metabolic disorders. Serum histidine levels are lower and are negatively associated with inflammation and oxidative stress in obese women. The objective of this study was to evaluate the efficacy of histidine supplementation on IR, inflammation, oxidative stress and metabolic disorders in obese women with the metabolic syndrome (MetS). Methods A total of 100 obese women aged 33-51 years with BMI≥28 kg/m 2 and diagnosed with MetS were included following a health examination in the community hospital in this randomised, double-blinded, placebo-controlled trial. Participants were allocated to interventions by an investigator using sequentially numbered sealed envelopes and received 4 g/day histidine (n=50) or identical placebo (n=50) for 12 weeks. Participants then attended the same clinic every 2 weeks for scheduled interviews and to count tablets returned. Serum histidine, HOMA-IR, BMI, waist circumference, fat mass, serum NEFA, and variables connected to inflammation and oxidative stress were measured at baseline and 12 weeks. Participants, examining physicians and investigators assessing the outcomes were blinded to group assignment. In addition, the inflammatory mechanisms of histidine were also explored in adipocytes. CI 0.60, 3.44] in histidine supplementation group (n=45), respectively. There were significant correlations between changes in serum histidine and changes of IR and its risk factors. No side effects were observed during the intervention. In vitro study indicated that histidine suppresses IL6 and TNF mRNA expression and nuclear factor kappa-B (NF-κB) protein production in palmitic acid-induced adipocytes in a dose-dependent manner, and these changes were diminished by an inhibitor of NF-κB. Conclusions/interpretation Histidine supplementation could improve IR, reduce BMI, fat mass and NEFA and suppress inflammation and oxidative stress in obese women with MetS; histidine could improve IR through suppressed pro-inflammatory cytokine expression, possibly by the NF-κB pathway, in adipocytes. Trial registration www.chictr.org/cn/ChiCTR-TRC-11001551Electronic supplementary material The online version of this article