Tropical rhodolith beds are a major and belittled reef fish habitat.

Understanding habitat-level variation in community structure provides an informed basis for natural resources' management. Reef fishes are a major component of tropical marine biodiversity, but their abundance and distribution are poorly assessed beyond conventional SCUBA diving depths. Based on a baited-video survey of fish assemblages in Southwestern Atlantic's most biodiverse region we show that species composition responded mainly to the two major hard-bottom megahabitats (reefs and rhodolith beds) and to the amount of light reaching the bottom. Both megahabitats encompassed typical reef fish assemblages but, unexpectedly, richness in rhodolith beds and reefs was equivalent. The dissimilar fish biomass and trophic structure in reefs and rhodolith beds indicates that these systems function based on contrasting energy pathways, such as the much lower herbivory recorded in the latter. Rhodolith beds, the dominant benthic megahabitat in the tropical Southwestern Atlantic shelf, play an underrated role as fish habitats, and it is critical that they are considered in conservation planning.

Kallikrein-Kinin System Suppresses Type I Interferon Responses: A Novel Pathway of Interferon Regulation.

The Kallikrein-Kinin System (KKS), comprised of kallikreins (klks), bradykinins (BKs) angiotensin-converting enzyme (ACE), and many other molecules, regulates a number of physiological processes, including inflammation, coagulation, angiogenesis, and control of blood pressure. In this report, we show that KKS regulates Type I IFN responses, thought to be important in lupus pathogenesis. We used CpG (TLR9 ligand), R848 (TLR7 ligand), or recombinant IFN-α to induce interferon-stimulated genes (ISGs) and proteins, and observed that this response was markedly diminished by BKs, klk1 (tissue kallikrein), or captopril (an ACE inhibitor). BKs significantly decreased the ISGs induced by TLRs in vitro and in vivo (in normal and lupus-prone mice), and in human PBMCs, especially the induction of Irf7 gene (p < 0.05), the master regulator of Type I IFNs. ISGs induced by IFN-α were also suppressed by the KKS. MHC Class I upregulation, a classic response to Type I IFNs, was reduced by BKs in murine dendritic cells (DCs). BKs decreased phosphorylation of STAT2 molecules that mediate IFN signaling. Among the secreted pro-inflammatory cytokines/chemokines analyzed (IL-6, IL12p70, and CXCL10), the strongest suppressive effect was on CXCL10, a highly Type I IFN-dependent cytokine, upon CpG stimulation, both in normal and lupus-prone DCs. klks that break down into BKs, also suppressed CpG-induced ISGs in murine DCs. Captopril, a drug that inhibits ACE and increases BK, suppressed ISGs, both in mouse DCs and human PBMCs. The effects of BK were reversed with indomethacin (compound that inhibits production of PGE2), suggesting that BK suppression of IFN responses may be mediated via prostaglandins. These results highlight a novel regulatory mechanism in which members of the KKS control the Type I IFN response and suggest a role for modulators of IFNs in the pathogenesis of lupus and interferonopathies.

Impaired Subset Progression and Polyfunctionality of T Cells in Mice Exposed to Methamphetamine during Chronic LCMV Infection.

Methamphetamine (METH) is a widely used psychostimulant that severely impacts the host's innate and adaptive immune systems and has profound immunological implications. T cells play a critical role in orchestrating immune responses. We have shown recently how chronic exposure to METH affects T cell activation using a murine model of lymphocytic choriomeningitis virus (LCMV) infection. Using the TriCOM (trinary state combinations) feature of GemStone™ to study the polyfunctionality of T cells, we have analyzed how METH affected the cytokine production pattern over the course of chronic LCMV infection. Furthermore, we have studied in detail the effects of METH on splenic T cell functions, such as cytokine production and degranulation, and how they regulate each other. We used the Probability State Modeling (PSM) program to visualize the differentiation of effector/memory T cell subsets during LCMV infection and analyze the effects of METH on T cell subset progression. We recently demonstrated that METH increased PD-1 expression on T cells during viral infection. In this study, we further analyzed the impact of PD-1 expression on T cell functional markers as well as its expression in the effector/memory subsets. Overall, our study indicates that analyzing polyfunctionality of T cells can provide additional insight into T cell effector functions. Analysis of T cell heterogeneity is important to highlight changes in the evolution of memory/effector functions during chronic viral infections. Our study also highlights the impact of METH on PD-1 expression and its consequences on T cell responses.

Methamphetamine alters microglial immune function through P2X7R signaling.

BACKGROUND: Purinoceptors have emerged as mediators of chronic inflammation and neurodegenerative processes. The ionotropic purinoceptor P2X7 (P2X7R) is known to modulate proinflammatory signaling and integrate neuronal-glial circuits. Evidence of P2X7R involvement in neurodegeneration, chronic pain, and chronic inflammation suggests that purinergic signaling plays a major role in microglial activation during neuroinflammation. In this study, we investigated the effects of methamphetamine (METH) on microglial P2X7R. METHODS: ESdMs were used to evaluate changes in METH-induced P2X7R gene expression via Taqman PCR and protein expression via western blot analysis. Migration and phagocytosis assays were used to evaluate functional changes in ESdMs in response to METH treatment. METH-induced proinflammatory cytokine production following siRNA silencing of P2X7R in ESdMs measured P2X7R-dependent functional changes. In vivo expression of P2X7R and tyrosine hydroxylase (TH) was visualized in an escalating METH dose mouse model via immunohistochemical analysis. RESULTS: Stimulation of ESdMs with METH for 48 h significantly increased P2X7R mRNA (*p < 0.0336) and protein expression (*p < 0.022). Further analysis of P2X7R protein in cellular fractionations revealed increases in membrane P2X7R (*p < 0.05) but decreased cytoplasmic expression after 48 h METH treatment, suggesting protein mobilization from the cytoplasm to the membrane which occurs upon microglial stimulation with METH. Forty-eight hour METH treatment increased microglial migration towards Fractalkine (CX3CL1) compared to control (****p < 0.0001). Migration toward CX3CL1 was confirmed to be P2X7R-dependent through the use of A 438079, a P2X7R-competitive antagonist, which reversed the METH effects (****p < 0.0001). Similarly, 48 h METH treatment increased microglial phagocytosis compared to control (****p < 0.0001), and pretreatment of P2X7R antagonist reduced METH-induced phagocytosis (****p < 0.0001). Silencing the microglial P2X7R decreased TNF-α (*p < 0.0363) and IL-10 production after 48 h of METH treatment. Additionally, our studies demonstrate increased P2X7R and decreased TH expression in the striata of escalating dose METH animal model compared to controls. CONCLUSIONS: This study sheds new light on the functional role of P2X7R in the regulation of microglial effector functions during substance abuse. Our findings suggest that P2X7R plays an important role in METH-induced microglial activation responses. P2X7R antagonists may thus constitute a novel target of therapeutic utility in neuroinflammatory conditions by regulating pathologically activated glial cells in stimulant abuse.

Relative Role of Akt, ERK and CREB in Alcohol-Induced Microglia P2X4R Receptor Expression.

AIMS: Previously we have demonstrated altered microglia P2X4R expression in response to alcohol and pharmacological blockade with a selective P2X4R antagonist can reverse the action, suggesting that P2X4R play a role in mediating alcohol-induced effects on microglia. In the present study, we investigated the underlying signaling mediators, which may play a role in modulating P2X4R expression in microglia cells in response to alcohol. METHODS: Embryonic stem cell-derived microglia (ESdM) cells were used to investigate the potential mechanisms involved in the regulation of P2X4R in response to alcohol. Selective P2X4R antagonist and kinase inhibitors were used to further corroborate the signal transduction pathway through which alcohol modulates P2X4R expression in microglia. RESULTS: Alcohol (100 mM) suppressed phosphorylated AKT and ERK cascades in native ESdM cells. This alcohol-induced suppression was confirmed to be P2X4R-dependent through the use of a selective P2X4R antagonist and knockdown of P2XR4 by siRNA. Alcohol increased transcriptional activity of CREB. P2X4R antagonist blocked alcohol-induced effects on CREB, suggesting a P2X4R-mediated effect. CONCLUSION: These findings provide important clues to the underlying mechanism of purinoceptors in alcohol-induced microglia immune suppression.

Methamphetamine induces trace amine-associated receptor 1 (TAAR1) expression in human T lymphocytes: role in immunomodulation.

The novel transmembrane G protein-coupled receptor, trace amine-associated receptor 1 (TAAR1), represents a potential, direct target for drugs of abuse and monoaminergic compounds, including amphetamines. For the first time, our studies have illustrated that there is an induction of TAAR1 mRNA expression in resting T lymphocytes in response to methamphetamine. Methamphetamine treatment for 6 h significantly increased TAAR1 mRNA expression (P < 0.001) and protein expression (P < 0.01) at 24 h. With the use of TAAR1 gene silencing, we demonstrate that methamphetamine-induced cAMP, a classic response to methamphetamine stimulation, is regulated via TAAR1. We also show by TAAR1 knockdown that the down-regulation of IL-2 in T cells by methamphetamine, which we reported earlier, is indeed regulated by TAAR1. Our results also show the presence of TAAR1 in human lymph nodes from HIV-1-infected patients, with or without a history of methamphetamine abuse. TAAR1 expression on lymphocytes was largely in the paracortical lymphoid area of the lymph nodes with enhanced expression in lymph nodes of HIV-1-infected methamphetamine abusers rather than infected-only subjects. In vitro analysis of HIV-1 infection of human PBMCs revealed increased TAAR1 expression in the presence of methamphetamine. In summary, the ability of methamphetamine to activate trace TAAR1 in vitro and to regulate important T cell functions, such as cAMP activation and IL-2 production; the expression of TAAR1 in T lymphocytes in peripheral lymphoid organs, such as lymph nodes; and our in vitro HIV-1 infection model in PBMCs suggests that TAAR1 may play an important role in methamphetamine -mediated immune-modulatory responses.

Reliability of the Robinson classification for displaced comminuted midshaft clavicular fractures.

This study aimed to assess the reliability of the Robinson classification for displaced comminuted midshaft fractures. A total of 102 surgeons and 52 radiologists classified 15 displaced comminuted midshaft clavicular fractures on anteroposterior (AP) and 30-degree caudocephalad radiographs twice. For both surgeons and radiologists, inter-observer and intra-observer agreement significantly improved after showing the 30-degree caudocephalad view in addition to the AP view. Radiologists had significantly higher inter- and intra-observer agreement than surgeons after judging both radiographs (κmultirater of 0.81 vs. 0.56; κintra-observer of 0.73 vs. 0.44). We advise to use two-plane radiography and to routinely incorporate the Robinson classification in the radiology reports.

Online radiographic survey of midshaft clavicular fractures: no consensus on treatment for displaced fractures.

The choice of treatment for midshaft clavicular fractures is not straightforward, but depends on fracture characteristics such as comminution, angulation and displacement. An online survey was conducted amongst trauma and orthopaedic surgeons to determine the preferred treatment for midshaft clavicular fractures, based on anteroposterior radiographs, for 17 randomly selected displaced or comminuted midshaft clavicular fractures. The background and experience of the respondents were documented. Data were analyzed using a Generalized Estimating Equations (GEE) model. The 102 respondents preferred non-operative treatment more frequently for displaced fractures than for comminuted fractures (OR 3.24, 95% CI 2.55-4.12). Locking plate fixation was more often preferred over other surgical modalities for comminuted than for displaced fractures (OR 1.50, 95% CI 1.17-1.91). In clinical practice, there is no consensus between surgeons on the choice of treatment for displaced or comminuted midshaft clavicular fractures. This lack of agreement calls for evidence-based treatment guidelines for these fractures.

Online radiographic survey of midshaft clavicular fractures: no consensus on treatment for displaced fractures.

The choice of treatment for midshaft clavicular fractures is not straightforward, but depends on fracture characteristics such as comminution, angulation and displacement. An online survey was conducted amongst trauma and orthopaedic surgeons to determine the preferred treatment for midshaft clavicular fractures, based on anteroposterior radiographs, for 17 randomly selected displaced or comminuted midshaft clavicular fractures. The background and experience of the respondents were documented. Data were analyzed using a Generalized Estimating Equations (GEE) model. The 102 respondents preferred non-operative treatment more frequently for displaced fractures than for comminuted fractures (OR 3.24, 95% CI 2.55-4.12). Locking plate fixation was more often preferred over other surgical modalities for comminuted than for displaced fractures (OR 1.50, 95% CI 1.17-1.91). In clinical practice, there is no consensus between surgeons on the choice of treatment for displaced or comminuted midshaft clavicular fractures. This lack of agreement calls for evidence-based treatment guidelines for these fractures.