Cocaine exerts its stimulant effect by inhibiting dopamine (DA) reuptake, leading to increased dopamine signaling. This action is thought to reflect the binding of cocaine to the dopamine transporter (DAT) to inhibit its function. However, cocaine is a relatively weak inhibitor of DAT, and many DAT inhibitors do not share cocaine’s behavioral actions. Further, recent reports show more potent actions of the drug, implying the existence of a high-affinity receptor for cocaine. We now report high-affinity binding of cocaine associated with the brain acid soluble protein 1 (BASP1) with a dissociation constant (Kd) of 7 nM. Knocking down BASP1 in the striatum inhibits [3H]cocaine binding to striatal synaptosomes. Depleting BASP1 in the nucleus accumbens but not the dorsal striatum diminishes locomotor stimulation in mice. Our findings imply that BASP1 is a pharmacologically relevant receptor for cocaine.
Abstract Protein functional effector sncRNAs (pfeRNAs) are approximately 30–60 nucleotides (nt), of which the extraction method from plasma has not yet been reported. Silver staining in a high-resolution polyacrylamide gel suggested that the majority of plasma sncRNAs extracted by some broadly used commercial kits were sncRNAs from 100 nt upwards. Additionally, TRIzol’s protocol is for long RNA but not sncRNA recovery. Here, we report a TRIzol-based frozen precipitation method (TFP method), which shows rigor and reproducibility in high yield and quality for plasma sncRNAs approximately 30–60 nt. In contrast to the yields by the commercial kit, plasma sncRNAs extracted by the TFP method enriched more sncRNAs. We used four different pfeRNAs of 34 nt, 45 nt, 53 nt, and 58 nt to represent typical sizes of sncRNAs from 30 to 60 nt and compared their levels in the recovered sncRNAs by the TFP method and by the commercial kit. The TFP method showed lower cycle threshold (CT) values by 2.01–9.17 cycles in 38 plasma samples from 38 patients, including Caucasian, Asian, African American, Latin, Mexican, and those who were a mix of more than one race. In addition, pfeRNAs extracted by two organic-based extraction methods and four commercial kits were undetermined in 22 of 38 samples. Thus, the quick and unbiased TFP method enriches plasma sncRNA ranging from 30 to 60 nt.
Abstract Cocaine is a behavioral stimulant with substantial abuse potential related to its positively rewarding actions 1,2 . Cocaine inhibits the reuptake inactivation of neurotransmitters such as dopamine, serotonin, and norepinephrine at high nanomolar to low micromolar concentrations 2 . There is evidence for substantially more potent influences of cocaine. For instance, Calligaro and Eldefrawi reported binding of [ 3 H]cocaine to brain membranes with a dissociation constant of about 16 nM 3 . At 10 nM concentration, cocaine elicits environmental place conditioning in planarians 4 . Furthermore, 1nM cocaine enhances dopamine D2 receptor agonist-mediated signaling 5 . Inhibition of amine reuptake by cocaine is substantially less potent than some of these high affinity actions. Thus, evidence for a specific, high affinity receptor for cocaine that mediates its behavioral actions has been lacking. We now report high affinity binding of cocaine to the membrane-associated brain acid soluble protein-1 (BASP1) with a Kd of 7 nM. Knocking down BASP1 in the striatum inhibits [ 3 H]cocaine binding to striatal synaptosomes. Depletion of BASP1 in the nucleus accumbens diminishes locomotor stimulation, acquisition, and expression of locomotor sensitization to cocaine. Our findings indicate that BASP1 is a pharmacologically relevant receptor for cocaine and a putative therapeutic target for psychostimulant addiction.
Abstract Objectives: Myeloid derived suppressor cells (MDSCs) are immature cells that aid in cancer progression and dissemination via immune system suppression. Previous work has shown that CCR 2 (C-C chemokine receptor) and CCR 5 expression on MDSCs is increased in non-small cell lung cancer (NSCLC). We hypothesized that patients with lung cancer will have detectable peripheral MDSCs with CCR2 and CCR5 expression preoperatively, that it would decrease immediately postoperatively, and then increase longitudinally if tumor recurs. Materials & Methods: As part of a prospective longitudinal study, whole blood samples were obtained from patients suspected to have primary lung cancer prior to surgery. Patients were excluded if they were minors, could not provider consent, had malignancy within the past 10 years or any immunosuppressive condition. Blood samples were obtained prior to surgery or at follow-up in clinic and processed within 1 hour of acquisition. We stained samples via 2 different methods: 1) whole blood and 2) peripheral blood mononuclear cells (PBMC) extracted from Ficoll density gradient and determined that whole blood staining had superior results. Samples were analyzed via flow cytometer and gated after defining MO (monocytic)-MDSCs as CD33+HLADRlow/-CD14+ and PMN-MDSCs as CD33+HLADR-CD15+. MDSCs were reported as a percentage of live leukocytes and means were reported with T-test performed for statistical analysis. Results: A total of 18 patients were recruited with a median age of 69 years (63.8-75) and 61% (11/18) females. Adenocarcinoma was present in 16, carcinoid tumor in 1 and both adenocarcinoma and carcinoid tumor in 1 patient. Stage I and Stage II were the most common (66.7% and 22.2%, respectively). Majority of the tumors were in the right upper lobe (55.6%). There were 7 healthy controls with a median age of 29 years (28-43) and 71% females. There was a significantly increased proportion of MO-MDSCs in NSCLC patients preoperatively compared to healthy controls (11.64% versus 5.02%, p = 0.02). CCR2+CCR5+ MO-MDSCs were 0.85% in patients versus 0.06% in controls (p=0.04). No differences were noted with PMN-MDSCs. Five patients had post-operative follow up (mean 152 days) with an average decrease of 63% in MO-MDSCs, 68% in CCR2+CCR5+ MO-MDSCs and no recurrence of tumor on CT scans. Conclusion: Early results of this on-going study demonstrate the detection of circulating CCR2+CCR5+ MO-MDSCs in the preoperative whole blood of NSCLC patients compared to healthy controls. Resection of the tumor is associated with a decrease of these MO-MDSCs after treatment. We are evaluating if any increase in CCR2+CCR5+ MO-MDSC in long term will allow us to use it as an adjuvant tool along with CT monitoring as a biomarker of residual or recurrent disease. Citation Format: Hamza Khan, Anas Awan, Maria Shishikura, Carley Blevins, Kristen Rodgers, Yuping Mei, Wasay Nizam, Shun Ishiyama, Yun Chen, Richard Battafarano, Errol Bush, Stephen Broderick, Stephen Yang, Hajime Orita, Peng Huang, Ada Tam, Jinny Ha, Franck Housseau, Malcolm Brock. Monitoring of CCR2 and CCR5 expression on circulating myeloid derived suppressor cells (MDSCs) in non-small cell lung cancer as a correlate of minimum residual disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 271.
Cocaine is a behavioral stimulant with substantial abuse potential related to its positively rewarding actions. Definitive molecular mechanisms of action have not been established, though cocaine is known to inhibit the reuptake inactivation of monoamine neurotransmission at high nanomolar to low micromolar concentrations. There is evidence for significantly more potent neurochemical and behavioral actions of cocaine that could not be attributed to the inhibition of monoamine transporters. Thus, evidence for a specific, high affinity cocaine receptor that mediates its behavioral actions has been lacking. In the present study we report high affinity binding of cocaine to the membrane‐associated protein BASP1, which appears to be a pharmacologically relevant cocaine receptor. Utilizing affinity pull‐down, mass spectrometry and ligand binding assays, we establish that BASP1 is a high‐affinity cocaine binding protein (Kd 7 nM). Our data show that knocking down BASP1 in the nucleus accumbens or striatum (pre‐ and post‐synaptic) inhibits behavioral actions of cocaine and reduces [3H]cocaine binding to striatal synaptosomes respectively. Taken together, our data suggest that BASP1 is a high‐affinity receptor for cocaine. Support or Funding Information Funding this work was supported by U.S. Public Health Service Grants DA00266 and DA044123 to SHS and a NARSAD Young Investigator Grant (grant # 25360) from the Brain & Behavior Foundation to MMH.
Leukocyte common antigen-related (LAR) class protein tyrosine phosphatases (PTPs) are critical for axonal guidance; however, their relation to specific guidance cues is poorly defined. We here show that PTP-3, a LAR homolog in Caenorhabditis elegans, is involved in axon guidance regulated by Semaphorin-2A-signaling. PTPδ, one of the vertebrate LAR class PTPs, participates in the Semaphorin-3A (Sema3A)-induced growth cone collapse response of primary cultured dorsal root ganglion neurons from Mus musculus embryos. In vivo, however, the contribution of PTPδ in Sema3A-regualted axon guidance was minimal. Instead, PTPδ played a major role in Sema3A-dependent cortical dendritic growth. Ptpδ−/− and Sema3a−/− mutant mice exhibited poor arborization of basal dendrites of cortical layer V neurons. This phenotype was observed in both male and female mutants. The double-heterozygous mutants, Ptpδ+/−; Sema3a+/−, also showed a similar phenotype, indicating the genetic interaction. In Ptpδ−/− brains, Fyn and Src kinases were hyperphosphorylated at their C-terminal Tyr527 residues. Sema3A-stimulation induced dephosphorylation of Tyr527 in the dendrites of wild-type cortical neurons but not of Ptpδ−/−. Arborization of cortical basal dendrites was reduced in Fyn−/− as well as in Ptpδ+/−; Fyn+/− double-heterozygous mutants. Collectively, PTPδ mediates Sema3A-signaling through the activation of Fyn by C-terminal dephosphorylation. SIGNIFICANCE STATEMENT The relation of leukocyte common antigen-related (LAR) class protein tyrosine phosphatases (PTPs) and specific axon guidance cues is poorly defined. We show that PTP-3, a LAR homolog in Caenorhabditis elegans, participates in Sema2A-regulated axon guidance. PTPδ, a member of vertebrate LAR class PTPs, is involved in Sema3A-regulated cortical dendritic growth. In Sema3A signaling, PTPδ activates Fyn and Src kinases by dephosphorylating their C-terminal Tyr residues. This is the first evidence showing that LAR class PTPs participate in Semaphorin signaling in vivo.
