Differences In Receptor Expression Research Articles

Differential expression of nuclear hormone receptors by dendritic cell subsets in human vaginal mucosa and skin.

Nuclear hormone receptors (NHRs) expressed by dendritic cells (DCs), the major immune inducers and regulators, could play important roles in host immunity. Assessment of NHRs expressed by DCs in the vaginal mucosa (VM), in comparison with those expressed by DCs in other tissues, will thus help us understand the immunology of human vagina. This study identified 16 NHR transcripts that are differentially expressed among 8 different antigen-presenting cell (APC) subsets isolated from human VM, skin, and blood. The expression profiles of NHRs were largely tissue specific. VM APCs expressed increased levels of LXRA, RXRA, ESRRA, ESRRAP2, and PPARG, whereas skin and blood APCs expressed increased levels of NURR1, NOR1 and RARA. Of interest, female sex hormone receptors, ESR1 and PGR, were found to be mainly expressed by non-APC cell types in the VM; ESR1 by HLA-DR+CD34+ and PGR by HLA-DR- cells. ERα and PR were expressed by vimentin+ cells in the VM, but not in human skin. ERα, but not PR, was also expressed in CD10+ cells in the lamina propria of VM. In conclusion, NHR expression by APC subsets is tissue- and cell type-specific. Future studies on the roles of individual NHRs expressed by different cell types, including DC subsets, in the human VM are warranted.

The differential expression of toll like receptors and RIG-1 correlates to the severity of infectious diseases

The toll like receptors (TLRs) and RIG-1 are proteins involved in the initial reaction of the innate immune system to infectious diseases and, thus, can provide much information to the surgical pathologist in terms of the molecular dynamics of the infection. The TLRs (TLR1, 2, 3, 4, 7, 8) and RIG-1 distribution as determined by immunohistochemistry was examined in the following diseases: human papillomavirus (n = 30 including 15 squamous intraepithelial lesions (SIL), 5 cancers, and 10 controls); molluscum contagiosum (n = 8 including 4 controls), SARS-CoV2 (n = 52 including 20 mild, 5 fatal, and 27 controls) and reovirus infection as oncolytic therapy. Mild, regressing infection (molluscum contagiosum, mild SARS-CoV2 and low grade SIL) each showed the same pattern: marked up regulation of at least three of the TLRs/RIG-1 with decreased expression of none compared to the controls. Severe infection (fatal SARS-CoV2, and cervical cancer) each showed marked decrease expression in at least three of the TLRs/RIG-1. We recently documented an equivalent marked decrease expression of the TLRs/RIG-1 in the placenta in fatal in utero infections. The reoviral infected tissues showed an overall pattern of marked increase expression of TLRs/RIG-1, consistent with a strong anti-viral response. Thus, the in situ testing of infectious diseases by a panel of these early infectious disease recognition proteins may allow the surgical pathologist to predict the outcome of the disease which, in turn, may assist in the understanding of the role of the TLRs/RIG-1 in determining the fate of a given infectious process.

Chlamydia trachomatis antigen induces TLR4-TAB1-mediated inflammation, but not cell death, in maternal decidua cells.

During gestation, the decidua is an essential layer of the maternal-fetal interface, providing immune support and maintaining inflammatory homeostasis. Although Chlamydia (C.) trachomatis is associated with adverse pregnancy outcomes the pathogenic effects on maternal decidua contributing to adverse events are not understood. This study examined how C. trachomatis antigen affects cell signaling, cell death, and inflammation in the decidua. Primary decidua cells (pDECs) from term, not-in-labor, fetal membrane-decidua were cultured using the following conditions: (1) control - standard cell culture conditions, (2) 100ng/ml or (3) 200ng/ml of C. trachomatis antigen to model decidual cell infection in vitro. Differential expression of Toll-like receptor (TLR) 4 (receptor for C. trachomatis antigen), signaling pathway markers phosphorylated TGF-Beta Activated Kinase 1 (PTAB1), TAB1, phosphorylated p38 mitogen-activated protein kinases (Pp38 MAPK), and p38 MAPK (western blot), decidual cell apoptosis and necrosis (flow cytometry), and inflammation (ELISA for cytokines) were determined in cells exposed to C. trachomatis antigen. T-test was used to assess statistical significance (p<0.05). C. trachomatis antigen significantly induced expression of TLR4 (p=0.03) and activation of TAB1 (p=0.02) compared to controls. However, it did not induce p38 MAPK activation. In addition, pDECs maintained their stromal cell morphology when exposed to C. trachomatis antigen showing no signs of apoptosis and/or necrosis but did induce pro-inflammatory cytokine interleukin (IL)-6 (100ng/ml: p=0.02 and 200ng/ml: p=0.03), in pDECs compared to controls. Prenatal C. trachomatis infection can produce antigens that induce TLR4-TAB1 signaling and IL-6 inflammation independent of Pp38 MAPK and apoptosis and necrosis. This suggests that C. trachomatis can imbalance decidual inflammatory homeostasis, potentially contributing to adverse events during pregnancy.

The differential expression of toll like receptors and RIG-1 in the placenta of neonates with in utero infections

Novel biomarkers of in utero infections are needed to help guide early therapy. The toll like receptors (TLRs) and retinoic acid-inducible gene 1 (RIG-1) are proteins involved in the initial reaction of the innate immune system to infectious diseases. This study tested the hypothesis that a panel of TLRs and RIG-1 in the placenta could serve as an early biomarker of in utero infections. The TLRs and RIG-1 expression as determined by immunohistochemistry was scored in 10 control placentas (normal delivery or neonatal damage from known non-infectious cause), 8 placentas from documented in utero bacterial infection, and 7 placentas from documented in utero viral infections blinded to the clinical information. The non-infected placentas showed the following profile: no expression (TLR1, TLR3, TLR4, TLR7, TLR8), moderate expression (TLR2), and strong expression (RIG-1). The bacterial and viral infection cases shared the following profile: no to mild expression (TLR 2, TLR7, and RIG1), moderate expression (TLR4), and strong expression (TLR1, TLR3, and TLR8). The histologic findings in the chorionic villi were equivalent in the infected cases and controls, underscoring the need for molecular testing by the surgical pathologist when in utero infection is suspected. The results suggest that a panel of TLRs/RIG-1 analyses can allow the pathologist and/or clinician to diagnose in utero infections soon after birth. Also, treatments to antagonize the effects of TLR1, 3, and 8 may help abrogate in utero neonatal damage.

Susceptibility of aged pericytes to Aβ1‐42 oligomers

AbstractBackgroundAging is associated with increased incidence of Alzheimer’s disease, blood brain barrier breakdown, and increased cellular senescence (Saez‐Atienzar et. al, 2020). Senescence is the permanent arrest of the proliferative state of the cell and is initiated as a result of aging and cellular stress (Martínez‐Cué et.al, 2020). Senescent cells induce production of proinflammatory cytokines. In the brain, chronic inflammation leads to synapse damage and cognitive decline (Saez‐Atienzar et. al, 2020). The objective of this study is to examine the impact of cellular senescence on brain vascular pericytes, which contribute to the regulation of cerebral blood flow.MethodFor this study, both in vitro as well as in vivo experiments were performed. To induce senescence by oxidative stress in vitro in a culture of mouse brain vascular pericytes, 100 uM of hydrogen peroxide was added to culture flasks. Senescence was confirmed in the treated cells via staining for β‐galactosidase, a known biomarker of senescent cells. The next steps for the in vitro aspects of this study include performing western blotting on senescent pericytes to determine if there is a differential expression of pericyte p75 neurotrophin receptor (p75NTR), which has a potential role in the impaired hemodynamic response and cell death in pericytes. Finally, cranial window procedures were performed on 18‐month‐old C57BL/6 mice followed by imaging the live brain tissue with a multiphoton microscope. While imaging, artificial cerebral spinal fluid (control animals) or 72 nM amyloid‐beta (Aβ)1‐42 oligomers were topically delivered to the brain surface to determine if Aβ1‐42 oligomers cause a significant reduction in erythrocyte flow through pericyte covered capillaries.ResultPreliminary data from the β‐galactosidase staining suggest that the hydrogen peroxide is an effective method for inducing senescence in mouse brain vascular pericytes. We have observed a decreased growth rate in cells treated with the hydrogen peroxide, further suggesting senescence in these cells.ConclusionThese findings characterize the impact of Aβ on pericyte contractility and could illuminate the role of senescence and aging on impaired hemodynamic responses because of dysfunctional pericytes.

Adolescent Δ-9-tetrahydrocannabinol exposure induces differential acute and long-term neuronal and molecular disturbances in dorsal vs. ventral hippocampal subregions.

Chronic exposure to Δ-9-tetrahydrocannabinol (THC) during adolescence is associated with long-lasting cognitive impairments and enhanced susceptibility to anxiety and mood disorders. Previous evidence has revealed functional and anatomical dissociations between the posterior vs. anterior portions of the hippocampal formation, which are classified as the dorsal and ventral regions in rodents, respectively. Notably, the dorsal hippocampus is critical for cognitive and contextual processing, whereas the ventral region is critical for affective and emotional processing. While adolescent THC exposure can induce significant morphological disturbances and glutamatergic signaling abnormalities in the hippocampus, it is not currently understood how the dorsal vs. ventral hippocampal regions are affected by THC during neurodevelopment. In the present study, we used an integrative combination of behavioral, molecular, and neural assays in a neurodevelopmental rodent model of adolescent THC exposure. We report that adolescent THC exposure induces long-lasting memory deficits and anxiety like-behaviors concomitant with a wide range of differential molecular and neuronal abnormalities in dorsal vs. ventral hippocampal regions. In addition, using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS), we show for the first time that adolescent THC exposure induces significant and enduring dysregulation of GABA and glutamate levels in dorsal vs. ventral hippocampus. Finally, adolescent THC exposure induced dissociable dysregulations of hippocampal glutamatergic signaling, characterized by differential glutamatergic receptor expression markers, profound alterations in pyramidal neuronal activity and associated oscillatory patterns in dorsal vs. ventral hippocampal subregions.

Multiomic Analysis of CD38 Expression Levels in 209 Untreated and Daratumumab-Resistant Patients

The anti-CD38 antibody Daratumumab (Dara) is widely used in first-line as well as in relapsed/refractory multiple myeloma (MM). Primary or secondary resistance eventually occurs in all treated patients but the underlying mechanisms are poorly understood: Genetic alterations that lead to loss of function affecting epitopes on CD38, low baseline expression of CD38 or the selection of CD38dim cells were associated with suboptimal response to treatment. Interestingly, drugs such as all-trans retinoic acid, panobinostat or DNMT inhibitors increase Dara efficiency through reversible upregulation of CD38. Overall, three cohorts with overall 209 patients were examined for this dataset. We conducted flow cytometry in 21 therapy naïve and 19 Dara-refractory patients using a Dara epitope-specific antibody. All untreated and 11 of the resistant patients stained positive for CD38 MM, suggesting CD38 independent resistance mechanisms. In eight patients, CD38 expression was not detected; however, in five of them, additional staining with a CD38 multiepitope antibody confirmed CD38 persistence, reflecting epitope blockade through Dara or epitope mutation that interferes with the binding of the antibody. Finally, in three out of 19 refractory patients, CD38 could not be detected with both antibodies. To quantify CD38 receptor density on a molecular level, we established super-resolution imaging by direct stochastic optical reconstruction microscopy (dSTORM) in the same patients. dSTORM uses fluorophore-conjugated antibodies and provides an unprecedented molecular 20 nm resolution for individual cells. We observed intra-patient heterogeneity of the CD38 receptor density with a mean expression of 35.15 ± 13.42 receptors/µm² (range 3.61-67.24) in the Dara naïve patients. Notably, in the refractory group, we found a significant decline (p=0.03) with a mean of 22.7 ± 18.26 receptors/µm² (range 17.07-63.77). In two of the three patients with no CD38 detectable, CD38 persistence could be assessed by dSTORM below the detection rate of flow cytometry. One patient remained negative for CD38, suggesting true loss of the receptor, causing Dara resistance in this patient. Next, we confirmed downregulation of CD38 gene expression using qPCR, and significantly reduced expression in the Dara refractory cohort (p=0.01). Of note, correlation between gene and receptor expression was moderate (p=0.49, r=0.57), leaving room for epigenetic regulation or posttranscriptional modification. To interrogate whether epigenetic regulation of CD38 via DNA methylation may underlie differential CD38 receptor expression, we performed deep bisulfite sequencing of MM cells and PBMCs obtained from 41 patients from our institution. CD38 on chromosome 4 contains several regulatory regions: One promoter, two adjacent promoter flanking regions and 11 enhancer regions described in ENSEMBL genome browser (GRCh38.13). The CD38 promoter was fully unmethylated (mean methylation: 0.31% ± 0.2%, range 0.2%-0.9%), but variable methylation of a CD38 promoter flanking region upstream of the promoter was detectable with 30.08% ± 17.8% (range 0.9%-61.5%) in the MM cells compared to 59.6% ± 3.9% (range 49.0%-66.7%) in the PBMCs from the same patients (p <0.001). This highlights phenotypic plasticity and suggests that DNA methylation may play a regulatory role in CD38 expression. We are currently investigating the methylome of all 14 regulatory regions in 38 Dara resistant patients (18 of them with longitudinal sampling before and after Dara therapy), 33 Dara responsive patients and 52 plasma cells obtained from healthy donors. Finally, in a cohort of 127 patients from our institution with WGS data available we screened for genetic alterations with potential impact on the CD38 receptor expression. We found monoallelic CD38 deletions in 18 patients, with one patient having an additional 11kb deletion conferring to an exon 3 loss. Exon-6 skipping, as recently described, was not detectable in the cohort. In conclusion, genetic alterations affecting the CD38 locus and true loss of the CD38 receptor are rare events and do not explain Dara resistance in most affected patients. dSTORM imaging provides additional insights in the CD38 receptor downregulation in MM patients treated with anti-CD38 moAb therapy. Regulatory mechanisms such as epigenetic regulation need to be further explored.

Biochemical Basis of Selective Accumulation and Targeted Delivery of Photosensitizers to Tumor Tissues.

The method of photodynamic therapy for treatment of malignant neoplasms is based on the selective of accumulation of photosensitizers in the tumor tissue. Insufficient selectivity of photosensitizers in relation to pathologically altered tissues and generalized distribution throughout the body leads to the development of severe toxic effects, including skin phototoxicity. The mechanisms underlying selectivity of photosensitizers for tumor tissue include selective binding to blood proteins and lipoproteins (considering that the number of receptors for those is increased on tumor cell membranes), uptake by macrophages, better solubility at low pH (acidic pH is characteristic of tumor cells), and other mechanisms. At present, increase in the efficiency of photodynamic therapy is largely associated with the additional targeting of photosensitizers to tumor tissues. Targeted delivery strategies are based on the differences in metabolism and gene expression profiles between the tumor and healthy cells. There are differences in expression of receptors, proteases, or transmembrane transporters in these cells. In particular, accelerated metabolism in many types of tumors leads to overexpression of receptors for epidermal growth factor, folic acid, transferrin, and a number of other compounds. This review considers biochemical basis for the selective accumulation of various classes of photosensitizers in tumors (chlorins, phthalocyanines, 5-aminolevulinic acid derivatives, etc.) and discusses various strategies of targeted delivery with emphasis on conjugation of photosensitizers with the receptor ligands overexpressed in tumor cells.

Determining biomarkers for evaluation and diagnosis of hereditary angioedema.

RationaleKallikrein‐bradykinin‐forming cascade is known to cause hereditary angioedema (HAE) acute angioedema (AE) attacks. Further research of HAE attacks is needed to explain disease heterogeneity, predict treatment response and identify biomarkers for monitoring HAE attacks. Differential expression of the microvascular endothelial cell‐surface receptors for example, g‐C1qR, cytokeratin‐1, and plasminogen‐activator‐urokinase‐receptor (PLAUR) were hypothesized as biomarkers of AE attacks.MethodTo understand HAE attacks, the differentially expressed genes (DEGs) in RNAseq and mi‐RNAseq data of total RNA extracted from skin biopsies of lesional versus non‐lesional skin collected during and between attacks in Type‐1 HAE patients (n = 11; F:M = 8:3) were compared. To understand the HAE variants, DEGs in skin biopsies from HAE with normal C1 inhibitor (n = 5, F:M = 5:0), and non‐HAE (n = 7; F:M = 3:4) patients were compared. Gene‐set enrichment analyses and regulator effects analysis of these DEGs identified biological pathways in HAE attacks and their regulators.ResultsPLAUR gene, encoding urokinase‐type plasminogen activator (u‐PAR), was constitutively over‐expressed in HAE‐Type‐1 versus non‐HAE controls suggestive of overactive u‐PAR‐mediated signaling via binding to Factor‐XII. Baseline PLAUR expression was associated with severe AE (p = 0.05). The 18 significant DEGs investigated between baseline and AE attack samples in Type1‐HAE were enriched in beta1/beta3‐integrin cell surface interactions and IL‐6‐mediated signaling. Regulator effects analysis suggests a role for IL‐1b in HAE flares. AKT2, the mRNA regulated by the differentially‐expressed miR‐184A, was also associated with HAE attacks.ConclusionAngiopoetin‐activated β1‐integrin signaling pathways causing endothelial destabilization, and avid binding of factor XII to u‐PAR are possible novel mechanisms for progression of the endothelial kinin‐bradykinin‐forming cascade in HAE attacks.

Chromatin remodeler Znhit1 controls bone morphogenetic protein signaling in embryonic lung tissue branching

Branching morphogenesis is a key process essential for lung and other organ development in which cellular and tissue architecture branch out to maximize surface area. While this process is known to be regulated by differential gene expression of ligands and receptors, how chromatin remodeling regulates this process remains unclear. Znhit1 (zinc finger HIT-type containing 1), acting as a chromatin remodeler, has previously been shown to control the deposition of the histone variant H2A.Z. Here, we demonstrate that Znhit1 also plays an important role in regulating lung branching. Using Znhit1 conditional KO mice, we show that Znhit1 deficiency in the embryonic lung epithelium leads to failure of branching morphogenesis and neonatal lethality, which is accompanied by reduced cell proliferation and increased cell apoptosis of the epithelium. The results from the transcriptome and the chromatin immunoprecipitation assay reveal that this is partially regulated by the derepression of Bmp4, encoding bone morphogenetic protein (BMP) 4, which is a direct target of H2A.Z. Furthermore, we show that inhibition of BMP signaling by the protein inhibitor Noggin rescues the lung branching defects of Znhit1 mutants ex vivo. Taken together, our study identifies the critical role of Znhit1/H2A.Z in embryonic lung morphogenesis via the regulation of BMP signaling.

Langerin-expressing dendritic cells in pulmonary immune-related diseases.

Dendritic cells (DCs) are “frontline” immune cells dedicated to antigen presentation. They serve as an important bridge connecting innate and adaptive immunity, and express various receptors for antigen capture. DCs are divided into various subclasses according to their differential expression of cell surface receptors and different subclasses of DCs exhibit specific immunological characteristics. Exploring the common features of each sub-category has became the focus of many studies. There are certain amounts of DCs expressing langerin in airways and peripheral lungs while the precise mechanism by which langerin+ DCs drive pulmonary disease is unclear. Langerin-expressing DCs can be further subdivided into numerous subtypes based on the co-expressed receptors, but here, we identify commonalities across these subtypes that point to the major role of langerin. Better understanding is required to clarify key disease pathways and determine potential new therapeutic approaches.

Dog and human bladders have different neurogenic and nicotinic responses in inner versus outer detrusor muscle layers.

The aim of this study was to investigate layer and species variations in detrusor muscle strip responses to myogenic, neurogenic, and nicotinic, and muscarinic receptor stimulations. Strips from bladders of 9 dogs and 6 human organ transplant donors were dissected from inner and outer longitudinal muscle layers, at least 1 cm above urethral orifices. Strips were mounted in muscle baths and maximal responses to neurogenic stimulation using electrical field stimulation (EFS) and myogenic stimulation using potassium chloride (KCl, 120 mM) determined. After washing and re-equilibration was completed, responses to nicotinic receptor agonist epibatidine (10 μM) were determined followed by responses to EFS and muscarinic receptor agonist bethanechol (30 μM) in continued presence of epibatidine. Thereafter, strips and full-thickness bladder sections from four additional dogs and three human donors were examined for axonal density and intramural ganglia. In dog bladders, contractions to KCl, epibatidine, and bethanechol were 1.5- to 2-fold higher in the inner longitudinal muscle layer, whereas contractions to EFS were 1.5-fold higher in the outer (both pre- and post-epibatidine). Human bladders showed 1.2-fold greater contractions to epibatidine in the inner layer and to EFS in the outer, yet no layer differences to KCl or bethanechol were noted. In both species, axonal density was 2- to 2.5-fold greater in the outer layer. Dogs had more intramural ganglia in the adventitia/serosa layer, compared with more internal layers and to humans. These findings indicate several layer-dependent differences in receptor expression or distribution, and neurogenic responses in dog and human detrusor muscles, and myogenic/muscarinic differences between dog versus humans.

Mast cell tissue heterogeneity and specificity of immune cell recruitment.

Mast cells occupy a unique niche within tissues as long lived perpetrators of IgE mediated hypersensitivity and anaphylaxis, as well as other immune responses. However, mast cells are not identical in different tissues and the impact of this tissue heterogeneity on the interaction with other immune cells and on defined immune responses is still unclear. In this review, we synthesize the characteristics of mast cell heterogeneity in the gut and the skin. Furthermore, we attempt to connect mast cell heterogeneity with functional diversity by exploring differences in mast cell-induced immune cell recruitment in these two model organs. The differential expression of certain receptors on mast cells of different tissues, notably tissue-specific expression patterns of integrins, complement receptors and MRGPRX2, could indicate that tissue environment-dependent factors skew mast cell-immune cell interactions, for example by regulating the expression of these receptors.

Neuregulin-1 signaling regulates cytokines and chemokines expression and secretion in granulosa cell

BackgroundGranulosa cells (GCs) are multilayered somatic cells within the follicle that provide physical support and microenvironment for the developing oocyte. In recent years, the role of Neuregulin-1 (NRG1), a member of the EGF-like factor family, has received considerable attention due to its neurodevelopmental and cardiac function. However, the exact physiological role of NRG1 in GC is mainly unknown. In order to confirm that NRG1 plays a regulatory role in rat GC functions, endogenous NRG1-knockdown studies were carried out in GCs using RNA interference methodology.ResultsKnockdown of NRG1 in GCs resulted in the enhanced expression and secretion of the cytokines and chemokines. In addition, the phosphorylation of PI3K/Akt/ERK1/2 was significantly low in GCs under these experimental conditions. Moreover, in vitro experimental studies suggest that tumor necrosis factor-α (TNFα) treatment causes the physical destruction of GCs by activating caspase-3/7 activity. In contrast, exogenous NRG1 co-treatment of GCs delayed the onset of TNFα-induced apoptosis and inhibited the activation of caspase-3/7 activity. Furthermore, current experimental studies suggest that gonadotropins promote differential expression of NRG1 and ErbB3 receptors in GCs of the antral follicle. Interestingly, NRG1 and ErbB3 were intensely co-localized in the mural and cumulus GCs and cumulus-oocyte complex of pre-ovulatory follicles in the estrus stage.ConclusionsThe present studies suggest that gonadotropins-dependent NRG1-signaling in GCs may require the balance of the cytokines and chemokines expression and secretion, ultimately which may be supporting the follicular maturation and oocyte competence for ovulation and preventing follicular atresia.

Notch signaling determines cell-fate specification of the two main types of vomeronasal neurons of rodents.

ABSTRACTThe ability of terrestrial vertebrates to find food and mating partners, and to avoid predators, relies on the detection of chemosensory information. Semiochemicals responsible for social and sexual behaviors are detected by chemosensory neurons of the vomeronasal organ (VNO), which transmits information to the accessory olfactory bulb. The vomeronasal sensory epithelium of most mammalian species contains a uniform vomeronasal system; however, rodents and marsupials have developed a more complex binary vomeronasal system, containing vomeronasal sensory neurons (VSNs) expressing receptors of either the V1R or V2R family. In rodents, V1R/apical and V2R/basal VSNs originate from a common pool of progenitors. Using single cell RNA-sequencing, we identified differential expression of Notch1 receptor and Dll4 ligand between the neuronal precursors at the VSN differentiation dichotomy. Our experiments show that Notch signaling is required for effective differentiation of V2R/basal VSNs. In fact, Notch1 loss of function in neuronal progenitors diverts them to the V1R/apical fate, whereas Notch1 gain of function redirects precursors to V2R/basal. Our results indicate that Notch signaling plays a pivotal role in triggering the binary differentiation dichotomy in the VNO of rodents.

Occlusion of dopamine-dependent synaptic plasticity in the prefrontal cortex mediates the expression of depressive-like behavior and is modulated by ketamine

Unpredictable chronic mild stress (CMS) is among the most popular protocols used to induce depressive-like behaviors such as anhedonia in rats. Differences in CMS protocols often result in variable degree of vulnerability, and the mechanisms behind stress resilience are of great interest in neuroscience due to their involvement in the development of psychiatric disorders, including major depressive disorder. Expression of depressive-like behaviors is likely driven by long-term alterations in the corticolimbic system and by downregulation of dopamine (DA) signaling. Although we have a deep knowledge about the dynamics of tonic and phasic DA release in encoding incentive salience and in response to acute/chronic stress, its modulatory action on cortical synaptic plasticity and the following implications on animal behavior remain elusive. Here, we show that the expression of DA-dependent synaptic plasticity in the medial prefrontal cortex (mPFC) is occluded in rats vulnerable to CMS, likely reflecting differential expression of AMPA receptors. Interestingly, such difference is not observed when rats are acutely treated with sub-anesthetic ketamine, possibly through the recruitment of dopaminergic nuclei such as the ventral tegmental area. In addition, by applying the synaptic activity sensor SynaptoZip in vivo, we found that chronic stress unbalances the synaptic drive from the infralimbic and prelimbic subregions of the mPFC toward the basolateral amygdala, and that this effect is counteracted by ketamine. Our results provide novel insights into the neurophysiological mechanisms behind the expression of vulnerability to stress, as well as behind the antidepressant action of ketamine.

The fatty acid synthase inhibitor C75 differentially affects the adipogenic differentiation of multipotent cells and preadipocytes.

Previously, we revealed the dual enhancing effect of netoglitazone, an agonist of the peroxisome proliferator-activated receptor γ, on adipogenesis and osteoblastogenesis, and reported that fatty acid synthase (FASN) knockdown selectively repressed its pro-adipogenic effect. Here, we examined if a FASN inhibitor, C75, could selectively repress the pro-adipogenic effect of netoglitazone. Surprisingly, C75 promoted the adipogenic differentiation of multipotent C3H10T1/2 cells but inhibited 3T3-L1 preadipocytes. By identifying glycogen synthase kinase-3β and intracellular cAMP levels as regulatory targets of C75, we ultimately found the differential expression of adenosine receptor 3 (AR3) and AR2a on these cells. Inhibition of AR3 on C3H10T1/2 and AR2a on 3T3-L1 inhibited the effects of C75 on the differentiation of these cells. Our findings imply that cell-type-specific AR expression might account for the differential adipogenic effects of C75.

Differential expression of serotonin2B receptors in GABAergic and serotoninergic neurons of the rat and mouse dorsal raphe nucleus

The central serotonin2B receptor (5-HT2BR) modulates 5-HT and dopamine (DA) neuronal function in the mammalian brain and has been suggested as a potential target for the treatment of neuropsychiatric disorders involving derangements of these monoamine systems, such as schizophrenia, cocaine abuse and dependence and major depressive disorder. Studies in rats and mice yielded contrasting results on the control of 5-HT/DA networks by 5-HT2BRs, thereby leading to opposite views on the therapeutic potential of 5-HT2BR agents for treating the above disorders. These discrepancies may result from anatomo-functional differences related to a different cellular location of 5-HT2BRs in rat and mouse brain. Using immunohistochemistry, we assessed this hypothesis by examining the expression of 5-HT2BRs in 5-HT and GABAergic neurons of rats and mice within different subregions of the dorsal raphe nucleus (DRN), currently considered as the main site of action of 5-HT2B agents. Likewise, using in vivo microdialysis, we examined their functional relevance in the control of DRN 5-HT outflow, a surrogate index of 5-HT neuronal activity.In the DRN of both species, 5-HT2BRs are expressed in 5-HT cells expressing tryptophan hydroxylase 2 (TPH2), in GABAergic cells expressing glutamic acid decarboxylase 67 (GAD67), and in cells expressing both markers (GAD67 & TPH2; i.e., GABA-expressing 5-HT neurons). The proportion of 5-HT2BR-positive cells expressing only TPH2 was significantly larger in mouse than in rat DRN, whereas the opposite holds true for the expression in cells expressing GAD67 & TPH2. No major species differences were found in the dorsal and ventral subregions. In contrast, the lateral subregion exhibited large differences, with a predominant expression of 5-HT2BRs in TPH2-positive cells in mice (67.2 vs 19.9 % in rats), associated with a lower expression in GAD67 & TPH2 cells (7.9 % in mice vs 41.5 % in rats). Intra-DRN (0.1 μM) administration of the preferential 5-HT2BR agonist BW 723C86 decreased and increased DRN 5-HT outflow in rats and mice respectively, both effects being prevented by the intra-DRN perfusion of the selective 5-HT2BR antagonist RS 127445 (0.1 μM).Altogether, these results show the existence of anatomical differences in the cellular expression of 5-HT2BRs in the rat and mouse DRN, which translate into an opposite control of 5-HT outflow. Also, they highlight the relevance of the subset of GAD67-positive 5-HT neurons as a key factor responsible for the functional differences between rats and mice in terms of 5-HT neuronal activity modulation.

Differential Expression of Duplicate Insulin-like Growth Factor-1 Receptors (igf1rs) in Medaka Gonads.

Insulin-like growth factor-1 receptors (igf1rs) play important roles in regulating development, differentiation, and proliferation in diverse organisms. In the present study, subtypes of medaka igf1r, igf1ra, and igf1rb were isolated and characterized. RT-PCR results showed that igf1ra and igf1rb mRNA were expressed in all tissues and throughout embryogenesis. Using real-time PCR, the differential expression of igf1ra and igf1rb mRNA during folliculogenesis was observed. The results of in situ hybridization (ISH) revealed that both of them were expressed in ovarian follicles at different stages, and igf1rb was also expressed in theca cells and granulosa cells. In the testis, both igf1ra and igf1rb mRNA were highly expressed in sperm, while igf1rb mRNA was also obviously detected in spermatogonia. In addition, igf1ra mRNA was also present in Leydig cells in contrast to the distribution of igf1rb mRNA in Sertoli cells. Collectively, we demonstrated that differential igf1rs RNA expression identifies medaka meiotic germ cells and somatic cells of both sexes. These findings highlight the importance of the igf system in the development of fish gonads.

Concomitant Expression of IL-6 and TGF-β Cytokines and their Receptors in Peripheral Blood of Patients with Multiple Sclerosis: The Effects of INFβ Drugs.

Concomitant signals from IL-6 and TGF-β have a central role in the Th17 cells development and differentiation, and these cells are the main promoters of demyelinating inflammation in the central nervous system (CNS) resulting in multiple sclerosis (MS). To evaluate the simultaneous IL-6 and TGF-β gene and their receptor protein expression in patients with Relapsing-Remitting (RR)-MS. IL-6 and TGF-β mRNA and their receptor expression on the surface of CD4+T cells were evaluated using real-time PCR (RT-PCR) and flow cytometry, respectively. The IL-6 mRNA expression in patients with RRMS was significantly higher than in the controls (p= 0.019). When patients who did not receive any other treatment were compared with the controls, the significant difference was substantial (p=0.006). The TGF-β mRNA expression in patients was lower than in the controls (p = 0.03). However, in patients receiving IFNβ, it increased compared with the other patients (p= 0.036). There was no difference in cytokine receptor expression between patients and the control group. Our data conclude an increase and decrease in mRNA expression levels of IL-6 and TGF-β in patients with RRMS, respectively. Moreover, there were no significant differences in receptor expression of either cytokines. Based on our data the balance of TGF and IL-6 appears to have a positive impact on the disease control.