Search

The idea of mid-level providers in dentistry grew from the increasing lack of access to oral care in rural and other underserved communities. To meet this need, dental therapists emerged. However, from an educational standpoint, the topic is hardly mentioned or discussed. This commentary discusses the role that dental therapists play in addressing oral health disparities and the reason more information about them should be included in dental and medical curricula. As the field of dentistry evolves and the lack of access to oral care persists, educating dental students and students in other healthcare professions about dental therapists should be an equally important task.

The complexity of the material being taught in clinical neuroscience within the medical school curriculum requires creative pedagogies to teach medical students effectively. Many clinical teaching strategies have been developed and are well described to address these challenges. However, only a few have been evaluated to determine their impact on the performance of students studying clinical neuroscience. Interactive, 2-hour, self-directed small-group interactive clinical case-based learning sessions were conducted weekly for 4 weeks to integrate concepts learned in the corresponding didactic lectures. Students in the small groups analyzed cases of patients suffering from neurological disease that were based on eight learning objectives that allowed them to evaluate neuroanatomical data and clinical findings before presenting their case analysis to the larger group. Students' performances on the formative quizzes and summative tests were compared to those of first-year medical students in the previous year for whom the self-directed, small-group interactive clinical sessions were not available. There was a significant improvement in the summative performance of first-year medical students with self-directed clinical case learning in the second year (Y2) of teaching clinical neuroscience (P < 0.05) when compared with first-year students in the first year (Y1) for whom the self-directed learning approach was not available. Student performance in the formative assessments between Y1 and Y2 was not significantly different (P = 0.803). A target of ≥70% student scoring above 80% in the final summative examination was met. The current study revealed evidence for the impact and educational outcomes of a self-directed, clinical teaching strategy in a clinical neuroscience curriculum for first-year medical students. Anat Sci Educ 11: 478-487. © 2017 American Association of Anatomists.

The original article was updated to include co-author Koen F. den Brok’s middle initial in the author list.

TNFα receptors are constitutively overexpressed in tumor cells, correlating to sustain elevated NFκB and monocyte chemotactic protein-1 (MCP-1/CCL2) expression. The elevation of CCL2 evokes aggressive forms of malignant tumors marked by tumor associated macrophage (TAM) recruitment, cell proliferation, invasion and angiogenesis. Previously, we have shown that the organo-sulfur compound diallyl disulfide (DADS) found in garlic (Allium sativum) attenuates TNFα induced CCL2 production in MDA-MB-231 cells. In the current study, we explored the signaling pathways responsible for DADS suppressive effect on TNFα mediated CCL2 release using PCR Arrays, RT-PCR and western blots. The data in this study show that TNFα initiates a rise in NFκB mRNA, which is not reversed by DADS. However, TNFα induced heightened expression of IKKε and phosphorylated ERK. The expression of these proteins corresponds to increased CCL2 release that can be attenuated by DADS. CCL2 induction by TNFα was also lessened by inhibitors of p38 (SB202190) and MEK (U0126) but not JNK (SP 600125), all of which were suppressed by DADS. In conclusion, the obtained results indicate that DADS down regulates TNFα invoked CCL2 production primarily through reduction of IKKε and phosphorylated-ERK, thereby impairing MAPK/ERK, and NFκB pathway signaling. Future research will be required to evaluate the effects of DADS on the function and expression of TNFα surface receptors.

Diallyl disulfide (DADS), a garlic organosulfur compound (OSC), has been researched as a cancer prevention agent; however, the role of DADS in the suppression of cancer initiation in non-neoplastic cells has not been elucidated. To evaluate DADS inhibition of early carcinogenic events, MCF-10A cells were pretreated (PreTx) with DADS followed by the ubiquitous carcinogen benzo(a)pyrene (BaP), or co-treated (CoTx) with DADS and BaP for up to 24 hours. The cells were evaluated for changes in cell viability/proliferation, cell cycle, induction of peroxide formation, and DNA damage. BaP induced a statistically significant increase in cell proliferation at 6 hours, which was attenuated with DADS CoTx. PreTx with 6 and 60 μM of DADS inhibited BaP-induced G2/M arrest by 68 and 78%, respectively. DADS, regardless of concentration or method, inhibited BaP-induced extracellular aqueous peroxide formation within 24 hours. DADS attenuated BaP-induced DNA single strand breaks at all time points through both DADS Pre- and CoTx, with significant inhibition for all treatments sustained after 6 hours. DADS was effective in inhibiting BaP-induced cell proliferation, cell cycle transitions, ROS, and DNA damage in a normal cell line, and thus may inhibit environmentally induced breast cancer initiation.

Trigeminal ganglia neurons express the GABA(A) receptor subunit alpha 6 (Gabrα6) but the role of this particular subunit in orofacial hypersensitivity is unknown. In this report the function of Gabrα6 was tested by reducing its expression in the trigeminal ganglia and measuring the effect of this reduction on inflammatory temporomandibular joint (TMJ) hypersensitivity. Gabrα6 expression was reduced by infusing the trigeminal ganglia of male Sprague Dawley rats with small interfering RNA (siRNA) having homology to either the Gabrα6 gene (Gabrα6 siRNA) or no known gene (control siRNA). Sixty hours after siRNA infusion the rats received a bilateral TMJ injection of complete Freund's adjuvant to induce an inflammatory response. Hypersensitivity was then quantitated by measuring meal duration, which lengthens when hypersensitivity increases. Neuronal activity in the trigeminal ganglia was also measured by quantitating the amount of phosphorylated ERK. Rats in a different group that did not have TMJ inflammation had an electrode placed in the spinal cord at the level of C1 sixty hours after siRNA infusion to record extracellular electrical activity of neurons that responded to TMJ stimulation. Our results show that Gabrα6 was expressed in both neurons and satellite glia of the trigeminal ganglia and that Gabrα6 positive neurons within the trigeminal ganglia have afferents in the TMJ. Gabrα6 siRNA infusion reduced Gabrα6 gene expression by 30% and significantly lengthened meal duration in rats with TMJ inflammation. Gabrα6 siRNA infusion also significantly increased p-ERK expression in the trigeminal ganglia of rats with TMJ inflammation and increased electrical activity in the spinal cord of rats without TMJ inflammation. These results suggest that maintaining Gabrα6 expression was necessary to inhibit primary sensory afferents in the trigeminal pathway and reduce inflammatory orofacial nociception.

Objective This study tested the effects of bisphosphonates (BPs) on the suppressor of cytokine signaling 3 (SOCS3) protein in macrophages. SOCS3 has been shown to regulate cell differentiation and survival; however, its potential role in mediating the effects of BPs has not been explored. Study design The cell viability of murine RAW 267.4 macrophages was assessed after culturing with control medium or media containing increasing concentrations of 2 BPs (ibandronate or clodronate) for 24, 48, and 72 hours. The phosphorylation status of signal transducer and activator of transcription 3 (STAT3) and the expression of SOCS3 protein levels were determined by Western blot analysis. Results In control cultures, STAT3 phosphorylation and STAT3 and SOCS3 protein levels increased within 5 minutes after the addition of fresh medium. This increase was inhibited in cultures treated with both BPs. Macrophage cell viability also decreased after BP treatment. Conclusions These data demonstrate that, in addition to their effects on macrophage viability, BPs can decrease STAT3 and SOCS3 expression, which are important modulators of immune responses and bone homeostasis.

We recently showed that acute oxidant-related lung injury (ALI) in rats after application of 2-chloroethyl ethyl sulfide (CEES) is attenuated by the airway instillation of antioxidants. We investigated whether intratracheal administration of antioxidant-containing liposomes immediately after instillation of CEES would attenuate short-term as well as long-term (fibrotic) effects of CEES-induced lung injury. In the acute injury model (4 h after injury), N-acetylcysteine (NAC)-containing liposomes were protective and reduced to baseline levels both the lung permeability index and the appearance of proinflammatory mediators in bronchoalveolar lavage fluids from CEES-exposed lungs. Similar results were obtained when rat alveolar macrophages were incubated in vitro with either CEES or lipopolysaccharide in the presence of NAC-liposomes. When lung fibrosis 3 weeks after CEES was quantitated by using hydroxyproline content, liposomes containing NAC or NAC + glutathione had no effects, but liposomes containing alpha/gamma-tocopherol alone or with NAC significantly suppressed the increase in lung hydroxyproline. The data demonstrate that delivery of antioxidants via liposomes to CEES-injured lungs is, depending on liposomal content, protective against ALI, prevents the appearance of proinflammatory mediators in bronchoalveolar fluids, and suppresses progressive fibrosis. Accordingly, the liposomal strategy may be therapeutically useful in CEES-induced lung injury in humans.

Neutrophil accumulation in the lung plays a pivotal role in the pathogenesis of acute lung injury during sepsis. Directed movement of neutrophils is mediated by a group of chemoattractants, especially CXC chemokines. Local lung production of CXC chemokines is intensified during experimental sepsis induced by cecal ligation and puncture (CLP), as reflected by rising levels of MIP-2 and cytokine-induced neutrophil chemoattractant-1 in bronchoalveolar lavage fluids. Alveolar macrophages are primed and blood neutrophils are down-regulated for production of MIP-2 and cytokine-induced neutrophil chemoattractant production in response to LPS and C5a. Under these conditions of stimulation, activation of MAPKs (p38, p42/p44) occurs in sham neutrophils but not in CLP neutrophils, while under the same conditions phosphorylation of p38 and p42/p44 occurs in both sham and CLP alveolar macrophages. These data indicate that, under septic conditions, there is impaired signaling in neutrophils and enhanced signaling in alveolar macrophages, resulting in CXC chemokine production, and C5a appears to play a pivotal role in this process. As a result, CXC chemokines increase in lung, setting the stage for neutrophil accumulation in lung during sepsis.

BACKGROUND Resuscitation from hemorrhagic shock triggers an inflammatory response characterized by upregulation of cytokine and adhesion molecule expression, increased leukocyte activity, and accumulation of polymorphonuclear neutrophils in a variety of tissues. This study investigated the capability of an exogenous nitric oxide (NO) donor, sodium nitroprusside (NP); a NO substrate, L-arginine; and an inducible NO synthase inhibitor, L-N6-(1-iminoethyl)lysine (L-NIL) to reduce lung injury in an animal model of mixed controlled and uncontrolled hemorrhagic shock. METHODS For this study, 72 Sprague-Dawley rats weighing 250 to 300 g were subjected to a model of uncontrolled hemorrhagic shock for 150 minutes. Six groups of animals were included in this study (12 per group): sham-saline, sham-NP, shock-saline, shock-NP, shock-L-arginine, and shock-L-N6-(1-iminoethyl)lysine. After the period of hemorrhagic shock, resuscitation of the groups was accomplished using normal saline (groups 1 and 3), NP (0.5 mg/kg) (groups 2 and 4), L-arginine (300 mg/kg) (group 5), or L-NIL (50 mg/kg) (group 6). The following indices were evaluated: fluid requirements for resuscitation, mean arterial pressure (MAP), arterial po2, pco2, and pH, lung wet-to-dry weight ratio, lung histology and cytokine (interleukin [IL]-1 alpha, IL-beta 1, tumor necrosis factor-beta [TNF beta], IL-3, IL-4, IL-5, IL-6, IL-10, TNF alpha, IL-2, interferon-gamma [IFN gamma]), and mRNA expression in the lung by a ribonuclease protection assay (RPA). RESULTS Sodium nitroprusside significantly increased MAP and reduced fluid requirements during resuscitation after hemorrhage. There also was a significant improvement in lung function, as expressed by improvements in po2, pco2, and pH, and reduction of the wet-to-dry weight ratio. In addition, a significant reduction in acute lung injury was observed in the histologic studies. Furthermore, the expression of cytokines was reduced by NP treatment. The use of L-arginine and L-NIL offered similar protective results for the injured lung. CONCLUSIONS These data suggest that limiting inducible NO synthase-generated NO availability with the exogenous NO donor, sodium nitroprusside, may reduce lung injury after severe hemorrhage, possibly, among other effects, by downregulating the expression of inflammatory cytokines. L-arginine and L-NIL also had a beneficial effect on lung function and structure.

Tissue damage after ischemia and reperfusion (I/R) is largely caused by the sequelae of neutrophil infiltration. This inflammatory process can be initiated as the result of stroke, coronary ischemia, trauma, and other related conditions. The infiltration of neutrophils is facilitated by the expression of adhesion molecules on the surface of endothelial cells. Particularly important are the selectin family of adhesion molecules at the onset of neutrophil-mediated injury. The aim of this study was to determine the role of selectin inhibition in the modulation of chemokine expression and Akt/MAPK signaling after liver I/R. In addition, we evaluated the optimal dose and time of administration of a small molecule selectin inhibitor, TBC-1269. Mice subjected to 90 min of partial (70-80%) hepatic ischemia followed by 3 h of reperfusion were divided into 15 groups (n = 4/group); sham, ischemic control, and 10, 20, and 40 mg/kg dose groups for the antiselectin molecule were studied at 3 times of drug administration: 1 h before reperfusion (but after ischemia), at the time of reperfusion, and at 15 min after reperfusion. The parameters measured after 3 h of reperfusion included liver function tests (ALT and AST), histopathology, and tissue myeloperoxidase (MPO). Chemokine expression (MIP-1alpha, MIP-1beta, MIP-2 and KC), Akt, MAPK (p44/p42), and RSK expressions were also measured in liver tissue by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis, respectively. It was demonstrated that the small molecule multi-selectin inhibitor (TBC-1269) offered the most significant protection for the ischemic liver when given at 40 mg/kg at the time ofreperfusion. AST significantly differed between the control group and the group receiving 40 mg/kg at the time of reperfusion (p = .01). MPO levels in the liver tissue of the ischemic controls were significantly increased when compared to the levels of this enzyme in the TBC-1269 group at 40 mg/kg. Histological examination reflected the same results, with a significant difference (p = .02) between these same two groups. The chemokine profile also showed that the same treatment group had a downregulation of MIP-lalpha, MIP-1beta, MIP-2, and KC, as well as a lower expression of Akt, MAPK(p44/42), and RSK when compared to the control group. Thus, we demonstrated that the small molecule selectin inhibitor, TBC-1269, offered significant functional and structural protection of the ischemic liver when given at 40 mg/kg at the time of reperfusion. Lower doses and different times of administration did not show as prominent a drug effect. This selectin inhibition modulated the expression of Akt, MAPK (p44/42), and RSK, as well as MIP-1alpha, MIP-1beta, MIP-2, and KC chemokines. These alterations in cellular signaling and chemokine expression represent potential mechanisms or pathways of inflammatory response in I/R.

In sepsis, there is evidence that excessive C5a generation leads to compromised innate immune functions, being associated with poor outcome. We now report that in vitro exposure of neutrophils to C5a causes increased levels of IkappaBalpha, decreased NF-kappaB-dependent gene transcription of TNFalpha, and decreased lipopolysaccharide (LPS)-induced TNFalpha production. Similar findings were obtained with neutrophils from cecal ligation/puncture (CLP)-induced septic rats. Such changes were reversed by antibody-induced in vivo blockade of C5a. In contrast, in vitro exposure of alveolar macrophages to C5a and LPS resulted in enhanced production of TNFalpha and no increase in IkappaBalpha. These data suggest that CLP-induced sepsis causes a C5a-dependent dysfunction of neutrophils, which is characterized by altered signaling associated with NF-kappaB activation.

Complement fragment 5a (C5a)-C5a receptor (C5aR) signaling plays an essential role in neutrophil innate immunity. Blockade of either the ligand or the receptor improves survival rates in experimental sepsis. In the current study, sepsis was induced in rats by cecal ligation/puncture. Early in sepsis C5aR content on neutrophils significantly dropped, reached the nadir at 24 h after onset of sepsis, and progressively elevated thereafter. Western-blot, RT-PCR, and confocal microscopy analyses revealed that the loss and re-expression of C5aR during sepsis might be due, at least in part, to the receptor internalization and reconstitution. The reduction and reconstitution of C5aR correlate with the loss and restoration of innate immune functions of blood neutrophils (chemotaxis and reactive oxygen species production), respectively. Quantitative measurements of C5aR on blood neutrophils are highly predictive of survival or death during sepsis. These data suggest that neutrophil C5aR content represents an essential component of an efficient defense system in sepsis and may serve as a prognostic marker for the outcome.

Our previous studies showed that S-adenosyl-methionine (SAM) induced Parkinson's disease-like changes in rat. It caused death to dopamine neurons in the substantia nigra, which appeared shrunken and fragmented, indicative of apoptosis-like changes (Charlton and Crowell [1995] Mol. Chem. Neuropathol. 26:269-284; Charlton [1997] Life Sci. 61:495-502). In this study, we investigated whether SAM causes apoptosis in both undifferentiated PC12 (PC12) cells and nerve growth factor (NGF)-differentiated PC12 (D-PC12) cells. S-adenosyl-homocysteine (SAH), the nonmethyl analog of SAM, was also tested. SAM and SAH (1.0 nM to 10.0 microM) caused lactate dehydrogenase (LDH) release from the PC12 cells and D-PC12 cells; cells with morphological changes and fluorescent DNA fragmentation staining were detected among both PC12 cell and D-PC12 cell. Compared with the PC12 cell, the D-PC12 cell, a postmitotic cell, was more sensitive to the toxic effects of SAM or SAH and presented much greater LDH release, suggesting a lethal effect; surprisingly, the amounts of apoptotic cells did not differ significantly between the two kinds of cells. In medium deprived of exogenous methionine, a decline in LDH release was observed in PC12 and D-PC12 cells. Also, lower levels of intracellular SAM and SAH were observed in the methionine-deleted media, which were reversed by the addition of either SAM or SAH. An antivitamin B(12) monoclonal antibody was added to methionine-depleted medium, resulting in deficiency of both endogenous and exogenous methionine, which caused further decreases in LDH release and reduction in the levels of intracellular SAM and SAH. The preliminary data showed different sensitivities to SAM or SAH between PC12 cell and D-PC12 cells, which suggests that PC12 cell may be more stable as a metabolic model. Apoptosis of PC12 cells was also assessed by PARP cleavage detection, Western blot analysis of Bax and Bcl-2 proteins, and DNA laddering on agarose gel electrophoresis. The proapoptoic protein Bax was dominantly expressed, whereas Bcl-2 was slightly down-regulated by SAM. SAH weakly induced the expression of Bax and slightly decreased Bcl-2 levels. The effects of SAM and its analog, SAH, were demonstrated conclusively to induce apoptosis in PC12 cells.

Dibutyryl cyclic AMP (dBcAMP) is known to induce maturation and differentiation in astrocytes. As myo-inositol is an important osmoregulator in astrocytes, we examined the effects of maturation and biochemical differentiation on the kinetic properties of myo-inositol transport. Treatment of astrocytes with dBcAMP significantly decreased the Vmax of myo-inositol uptake, but the effect on Km was not significant. The myo-inositol content of astrocytes was significantly decreased in cells treated for 5 days with dBcAMP as compared with untreated controls. Maximum suppression of myo-inositol uptake occurred 7 days after exposure of astrocytes to dBcAMP; this was gradually reversible when dBcAMP was removed from the medium. After exposure to hypertonic medium for 6 h, mRNA expression of the myo-inositol co-transporter was diminished by approximately 36% in astrocytes treated with dBcAMP as compared with untreated cells. It appears that myo-inositol transporters in astrocytes treated with dBcAMP are either decreased in number or inactivated during maturation and differentiation, suggesting that the stage of differentiation and biochemical maturation of astrocytes is an important factor in osmoregulation.

It is well known that there is a large disparity between the proportions of African Americans, Hispanics, and American Indians in the general U.S. population and in the nation's dental profession. While these underrepresented minorities (URMs) together make up almost 30 percent of the population, they comprise only about 6 percent of U.S. dentists. For years, the American Dental Education Association has been diligently working with U.S. dental schools to reduce this disparity by increasing the diversity of their student bodies. However, with approximately 13 percent of first-year dental students coming from URM groups, the proportion of URM students entering dental school continues to remain significantly below that of the general population. Diversifying the dental profession is important for improving access to care for underrepresented groups, and student diversity provides better educational experiences for all students. Texas AM Health Science Center Baylor College of Dentistry's strategy for increasing the number of URM dentists was to create a series of initiatives that together form a successful comprehensive program addressing students' awareness of and attraction to a dental career, academic enrichment, admissions, and graduation. The cumulative impact of this program is that the college enrolled greater numbers and proportions of URM students than any other non-minority U.S. dental school from 2006 to 2009. This article describes the program that led to these successes.

Diallyl trisulfide (DATS) is a garlic organosulfide that is toxic to cancer cells, however, little is known about its effect in the initiation phase of carcinogenesis. We sought to determine whether DATS could inhibit the carcinogen, benzo(a)pyrene (BaP), from inducing precancerous activity, in vitro. MCF-10A cells were either pre-treated (PreTx) or concurrently treated (CoTx) with 1 μM BaP, and 6 or 60 μM DATS for up to 24 hours. The DATS 6 and 60 μM CoTx inhibited BaP-induced cell proliferation by an average of 71.1 and 120.8%, respectively, at 6 hours. The 60 μM DATS pretreatment decreased BaP-induced G2/M cell cycle transition by 127 %, and reduced the increase in cells in the S-phase by 42%; whereas 60 μM DATS CoTx induced a 177% increase in cells in G1. DATS effectively inhibited (P

Suppressor of cytokine signaling-3 (SOCS3) has multiple functions including inhibition of Janus kinase activity, regulation of protein degradation, and suppression of cytokine signaling. SOCS3 modulates macrophage response to cytokines such as IL-6 and leptin that are systemically induced in obesity. Obesity is a suspected risk factor for SOCS3-related pathology such as rheumatoid arthritis and Crohn’s disease as well as zoledronic acid (ZA)-induced osteonecrosis of the jaw (ONJ). Thus, understanding the ability of bisphosphonates to modulate SOCS3 is necessary to qualify their contribution to these disorders. ONJ occurs in up to 10% of patients using intravenous bisphosphonates and has an unknown pathogenesis that may be linked to decreased bone turnover, altered vascularity, bacterial invasion, and compromised wound healing. Given the increased risk of ONJ with obesity and importance of macrophages in wound healing, we hypothesized that amino-bisphosphonates could contribute to the pathogenesis of ONJ by regulating macrophage responses to cytokines such as leptin and IL-6. We report that zoledronic acid is a novel inhibitor of SOCS3 in primary macrophages and human ONJ biopsy specimens. Inhibition of SOCS3 by ZA resulted in significant increases in IL-6 production. SOCS3 transcription is regulated by nuclear accumulation of phosphorylated-Stat3 (P-Stat3). We found that ZA decreased phosphorylation of Stat3 in a mevalonate-pathway dependent manner. However, restoration of P-Stat3 was not sufficient to correct SOCS3 inhibition. We propose that disruption of macrophage SOCS3 expression by amino-bisphosphonates such as ZA may be a novel contributor to inflammatory phenotypes in obesity and the pathogenesis of ONJ.

IgG complexes bind to Fc receptor family members FcgammaRI (CD64), FcgammaRII (CD32) and FcgammaRIII (CD16), activating cell MAPK and PI3K resulting in increased cytokine production from particular leukocytes. The signaling molecules involved in cytokine production after cross-linking CD16 have not been determined in monocytes. To address this question, TNF-alpha, IL-1beta and IL-6 were measured in activated monocytes after inhibiting MEK1/2, PI3K and glycogen synthase kinase-beta (GSK-3beta). The roles of GSK-3beta and NF-kappaB were then determined using reporter assays and siRNA treatment. The data suggested that an MAPK pathway stimulated TNF-alpha release but that active PI3K limited TNF-alpha, IL-1beta and IL-6 cytokine production after cross-linking CD16. PI3K was also shown to limit nuclear translocation of NF-kappaB. The limiting effect of PI3K on TNF-alpha production from activated monocytes depended on the decrease of GSK-3beta activity, which significantly reduced the transactivation of NF-kappaB. Moreover, the TNF-alpha production induced by CD16 cross-linking was reduced in monocytes after treatment with siRNA against NF-kappaB, implying that this transcription factor functioned in TNF-alpha production. The results suggest that CD16 cross-linking activated PI3K and that active PI3K limited TNF-alpha production by inhibiting GSK-3beta activity, that blocked the action of NF-kappaB.

Delayed neutrophil apoptosis is characteristic of sepsis and may accentuate organ injury. It has been shown that phosphatidylinositol 3-kinase (PI3-K) and MAPK pathways provide survival signaling in neutrophils. In this study, we demonstrate that neutrophils isolated from septic rats are resistant to apoptosis in comparison to the cells from normal animals. In contrast to normal serum, septic sera induced strong phosphorylation of AKT and p44/42 in neutrophils obtained from normal rats, resulting in marked resistance of these cells to apoptosis. Protection from apoptosis by septic sera was completely abrogated by inhibition of PI3-K and partially diminished by MAP kinase (MEK) inhibition. Increased neutrophil survival in septic rats was associated with increased levels of Bcl-xL in neutrophils and decreased levels of Bim expression. In vivo blockade of C5a in CLP rats by anti-C5a antibody markedly restored the susceptibility of neutrophils to undergo apoptosis. C5a activated AKT and p44/42, and also enhan...

Stat3 plays diverse roles in biological processes including cell proliferation, survival, apoptosis, and inflammation. Very little is known regarding its activation and function in the lung during acute inflammation. We now show that Stat3 activation was triggered in lungs and in alveolar macrophages after intrapulmonary deposition of IgG immune complexes in rats. Low levels of constitutive Stat3 were observed in normal rat lungs as determined by the EMSA. Stat3 activity in whole lung extracts increased 2 h after initiation of IgG immune complex deposition, reaching maximal levels by 4 h, whereas Stat3 activation was found in alveolar macrophages as early as 30 min after onset of injury. Expression and activation of Stat3 mRNA, protein, and protein phosphorylation was accompanied by increased gene expression of IL-6, IL-10, and suppressor of cytokine signaling-3 in whole lung tissues. Both Tyr705 and Ser727 phosphorylation were involved in Stat3 activation as assessed in whole lung extracts. C5a (complement 5, fragment a) per se can induce phosphorylation of Ser727 of Stat3. In vivo, Stat3 activation was dramatically suppressed by depletion of neutrophils or lung macrophages, resulting in reduced gene expression of IL-6 and IL-10 in whole lung tissues. Using blocking Abs to IL-6, IL-10, and C5a, Stat3 activation induced by IgG immune complexes was markedly diminished. These data suggest in the lung injury model used that activation of Stat3 in lungs is macrophage dependent and neutrophil dependent. IL-6, IL-10, and C5a contribute to Stat3 activation in inflamed rat lung.

Experimental sepsis in rodents occurring after cecal ligation/puncture (CLP) is associated with excessive complement activation and a systemic inflammatory response. The proinflammatory mediator IL-6 has recently been shown to be an important inducer of the C5a receptor (C5aR) during sepsis. We now provide evidence that serum IL-6 production during sepsis in rats was reduced in neutrophil-depleted animals and that absence of C5aR in mice as well as antibody-blockade of C5a in rats significantly reduced serum levels of IL-6 during sepsis. Lipopolysaccharide (LPS)-induced production in vitro of IL-6 by neutrophils was significantly enhanced in the co-presence of C5a, likely due to transcriptional up-regulation of IL-6. Production of IL-6 in neutrophils by LPS was NF-kappaB dependent (but not on the presence of p50) and dependent on phosphorylation of p38-mitogen activated protein kinase (MAPK) as well as p44/p42 MAPK (ERK1/2) but not on phosphorylation of c-Jun N-terminal kinases (JNK1/2). C5a stimulation of neutrophils elicited a rapid phosphorylation of ERK1/2 and p38 MAPK. Accordingly, we suggest that induction of IL-6 after CLP is neutrophil and C5a/C5aR dependent, likely due to the ability of C5a to cause activation of ERK1/2 and p38 MAPK signaling pathways.

Experimentally naive male Sprague Dawley rats (weighing 85–110 g) were used to examine the role of inducible nitric oxide synthase (iNOS) in cocaine-induced kindling. Repeated administration of cocaine (45 mg/kg, ip) to Sprague Dawley male rats for 7 consecutive days produced a progressive increase in the Convulsive responsiveness and death. Pretreatment with iNOS inhibitors, L-N6-(1-iminoethyl)lysine (NIL; 10 mg/kg, ip) and (–)-ePigalloocatechin gallate (EGCG; 10 mg/kg, ip) 30 min before cocaine (45 mg/kg, ip) administration for 7 days attenuated the development of cocaine kindling and blocked cocaine-induced death. Results of NMDA receptor binding assay in the hippocampus showed a significant increase in the affinity without changes in the density in animals treated with cocaine, but there were no changes in these parameters in the cortex. Pretreatment with NIL or EGCG prior to cocaine administration abolished the cocaine-induced effect in the NMDA receptor affinity in the hippocampus. These results suggest that iNOS induction followed by an increase of NMDA receptor affinity in the hippocampus after repeated exposure to cocaine may participate in the process of the development of cocaine kindling.

We measured lymphocyte proliferation in the absence of antigenic stimulation in 45 HTLV-II infected, 9 HTLV-I infected, and 19 HTLV-I seronegative intravenous drug users (IVDU). Lymphocyte proliferation was higher in IVDUs infected with HTLV-II than in seronegative IVDUs but lower than among those infected with HTLV-I. Higher rates of proliferation were also associated with needle sharing, CD4+ and IL2R+ lymphocyte counts, and HTLV-I antibody titres.