Mutations in TREM2, which has been proposed to regulate the inflammatory responses and the clearance of apoptotic neurons and/or amyloid-β (Aβ), are genetically linked to increased risk for late-onset Alzheimer’s disease (AD). Interestingly, a missense variant in TREM-like transcript 2 (TREML2), a structurally similar protein encoded by the same gene cluster with TREM2 on chromosome 6, has been shown to protect against AD. However, the molecular mechanisms by which TREM2 and TREML2 regulate the pathogenesis of AD, and their functional relationship, if any, remain unclear. Here, we show that lipopolysaccharide (LPS) stimulation significantly suppressed TREM2 but increased TREML2 expression in mouse brain. Consistent with this in vivo result, LPS or oligomeric Aβ treatment down-regulated TREM2 but up-regulated TREML2 expression in primary microglia. Importantly, modulation of TREM2 or TREML2 levels had opposing effects on inflammatory responses with enhancement or suppression of LPS induced pro-inflammatory cytokine gene expression observed upon TREM2 or TREML2 down-regulation, respectively. In addition, the proliferation of primary microglia was significantly decreased when TREM2 was down-regulated, whereas it was increased upon TREML2 knockdown. Together, our results suggest that several microglial functions are strictly regulated by TREM2 and TREML2, whose dysfunctions likely contribute to AD pathogenesis by impairing brain innate immunity. Our findings provide novel mechanistic insights into the functions of TREM2 and TREML2 in microglia and have implications on designing new therapeutic strategies to treat AD.

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Cytolethal distending toxins (CDTs) are common among pathogenic bacteria of the human and animal microbiota. CDTs exert cytopathic effets, via their active CdtB subunit. No clear description of those cytopathic effects has been reported at the cellular level in the target organs in vivo. In the present study, xenograft mouse models of colon and liver cell lines were set up to study the effects of the CdtB subunit of Helicobacter hepaticus. Conditional transgenic cell lines were established, validated in vitro and then engrafted into immunodeficient mice. After successful engraftment, mice were treated with doxycyclin to induce the expression of transgenes (red fluorescent protein, CdtB, and mutated CdtB). For both engrafted cell lines, results revealed a delayed tumor growth and a reduced tumor weight in CdtB-expressing tumors compared to controls. CdtB-derived tumors showed γ-H2AX foci formation, an increase in apoptosis, senescence, p21 and Ki-67 nuclear antigen expression. No difference in proliferating cells undergoing mitosis (phospho-histone H3) was observed. CdtB intoxication was also associated with an overexpression of cytokeratins in cells at the invasive front of the tumor as well as an increase in ploidy. All these features are hallmarks of endoreplication, as well as aggressiveness in cancer. These effects were dependent on the histidine residue at position 265 of the CdtB, underlying the importance of this residue in CdtB catalytic activity. Taken together, these data indicate that the CdtB triggers senescence and cell endoreplication leading to giant polyploid cells in these xenograft mouse models.

Background and objectives People with atherosclerotic renal artery stenosis may benefit from renin-angiotensin inhibitors, angiotensin-converting enzyme inhibitors, and angiotensin-receptor blockers, but little is known about the factors associated with their use.Design, setting, participants, & measurements The Cardiovascular Outcomes in Renal Atherosclerotic Lesions study (ClinicalTrials.gov identified: NCT00081731) is a prospective, international, multicenter clinical trial that randomly assigned participants with atherosclerotic renal artery stenosis who received optimal medical therapy to stenting versus no stenting from May 2005 through January 2010. At baseline, medication information was available from 853 of 931 randomly assigned participants. Kidney function was measured by serum creatininebased eGFR at a core laboratory.Results Before randomization, renin-angiotensin inhibitors were used in 419 (49%) of the 853 participants. Reninangiotensin inhibitor use was lower in those with CKD (eGFR,60 ml/min per 1.73 m 2 ) (58% versus 68%; P=0.004) and higher in individuals with diabetes (41% versus 27%; P,0.001). Presence of bilateral renal artery stenosis or congestive heart failure was not associated with renin-angiotensin inhibitor use. Although therapy with renin-angiotensin inhibitors varied by study site, differences in rates of use were not related to the characteristics of the site participants. Participants receiving a renin-angiotensin inhibitor had lower systolic BP (mean6SD, 148623 versus 152623 mmHg; P=0.003) and more often had BP at goal (30% versus 22%; P=0.01).Conclusions Kidney function and diabetes were associated with renin-angiotensin inhibitor use. However, these or other clinical characteristics did not explain variability among study sites. Patients with renal artery stenosis who received renin-angiotensin inhibitor treatment had lower BP and were more likely to be at treatment goal.

Cigarette smoking causes cardiovascular disease and is associated with poor kidney function in individuals with diabetes mellitus and primary kidney diseases. However, the association of smoking on patients with atherosclerotic renal artery stenosis has not been studied. The current study utilized data from the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL, NCT00081731) clinical trial to evaluate the effects of smoking on the risk of cardio-renal events and kidney function in this population. Baseline data showed that smokers (n = 277 out of 931) were significantly younger at enrollment than non-smokers (63.3±9.1 years vs 72.4±7.8 years; p<0.001). In addition, patients who smoke were also more likely to have bilateral renal artery stenoses and peripheral vascular disease (PVD). Longitudinal analysis showed that smokers experienced composite endpoint events (defined as first occurrence of: stroke; cardiovascular or renal death; myocardial infarction; hospitalization for congestive heart failure; permanent renal replacement; and progressive renal insufficiency defined as 30% reduction of GFR from baseline sustained for ≥ 60 days) at a substantially younger age compared to non-smokers (67.1±9.0 versus 76.1±7.9, p<0.001). Using linear regression and generalized linear modeling analysis controlled by age, sex, and ethnicity, smokers had significantly higher cystatin C levels (1.3±0.7 vs 1.2±0.9, p<0.01) whereas creatinine and estimated glomerular filtration rate (eGFR) were not different from non-smokers. From these data we conclude that smoking has a significant association with deleterious cardio-renal outcomes in patients with renovascular hypertension.

Humans are frequently exposed to bacterial genotoxins involved in digestive cancers, colibactin and Cytolethal Distending Toxin (CDT), the latter being secreted by many pathogenic bacteria. Our aim was to evaluate the effects induced by these genotoxins on nuclear remodeling in the context of cell survival. Helicobacter infected mice, coculture experiments with CDT- and colibactin-secreting bacteria and hepatic, intestinal and gastric cells, and xenograft mouse-derived models were used to assess the nuclear remodeling in vitro and in vivo. Our results showed that CDT and colibactin induced-nuclear remodeling can be associated with the formation of deep cytoplasmic invaginations in the nucleus of giant cells. These structures, observed both in vivo and in vitro, correspond to nucleoplasmic reticulum (NR). The core of the NR was found to concentrate ribosomes, proteins involved in mRNA translation, polyadenylated RNA and the main components of the complex mCRD involved in mRNA turnover. These structures are active sites of mRNA translation, correlated with a high degree of ploidy, and involve MAPK and calcium signaling. Additional data showed that insulation and concentration of these adaptive ribonucleoprotein particles within the nucleus are dynamic, transient and protect the cell until the genotoxic stress is relieved. Bacterial genotoxins-induced NR would be a privileged gateway for selected mRNA to be preferably transported therein for local translation. These findings offer new insights into the context of NR formation, a common feature of many cancers, which not only appears in response to therapies-induced DNA damage but also earlier in response to genotoxic bacteria.

Activation of the CD40 receptor on the proximal tubular epithelium of the kidney results in fibrosis and inflammation in experimental models of kidney injury. Soluble CD40 ligand is released by activated platelets. The role of CD40-soluble CD40 ligand in patients with ischemic renal disease is unknown. Plasma levels of CD40 and soluble CD40 ligand were measured by enzyme linked immunosorbent assay in a single center cohort of 60 patients with renal artery stenosis recruited from Salford Royal Hospital, Manchester, UK. A natural log transformation of CD40 and soluble CD40 ligand was performed to normalize the data. Estimated glomerular filtration rate was used as the primary indicator of renal function. By univariate analysis low baseline levels of circulating CD40 (R2=0.06, p<0.05) and baseline creatinine (R2=0.08, p=0.022) were associated with loss of kidney function at one-year follow-up, whereas soluble CD40 ligand was not (R2=0.02, p=ns). In a multiple linear regression model CD40 (p<0.02) and baseline creatinine (p<0.01) continued to be significantly associated with a decline in renal function (model R2=0.17, p<0.005). Baseline CD40 levels were somewhat lower in patients who died during follow-up (survivors, 7.3 ± 0.9 pg/ml, n=48 vs. non-survivors, 6.7 ± 1.0 pg/ml, n=12, p=0.06). The CD40/soluble CD40 ligand signaling cascade may be a novel mechanism contributing to the development and progression of renal injury in patients with atherosclerotic renal artery stenosis.

Dysregulation of microRNAs has been proposed to contribute toward epilepsy. The miRNA miR-23b-3p has been found to protect against neuronal apoptosis and the production of reactive oxygen species. In this study, we assessed the potential role of miR-23b-3p in the kainic acid (KA)-induced seizure model. We found that miR-23b-3p levels were significantly decreased in the brain cortex of mice and in cultured mouse primary neurons treated with KA. Importantly, supplement of miR-23b-3p agomir by an intacerebroventricular injection alleviated seizure behaviors and abnormal cortical electroencephalogram recordings in KA-treated mice. Together, these results indicate that miR-23b-3p plays a crucial role in suppressing seizure formation in experimental models of epilepsy and that miR-23b-3p supplement may be a potential anabolic strategy for ameliorating seizure.