Absence of PNET formation and normal longevity in a mouse model of Mahvash disease.

Mahvash disease, a rare autosomal recessive metabolic disorder characterized by biallelic loss-of-function mutations in the glucagon receptor gene (GCGR), induces significant pancreatic hyperglucagonemia, resulting in α-cell hyperplasia and occasional hypoglycemia. Utilizing CRISPR-Cas9 technology, we engineered a mouse model, designated as Gcgr V369M/V369M, harboring a homozygous V369M substitution in the glucagon receptor (GCGR). Although wild-type (WT) and Gcgr V369M/V369M mice exhibited no discernible difference in appearance or weight, adult Gcgr V369M/V369M mice, approximately 12 months of age, displayed a notable decrease in fasting blood glucose levels and elevated the levels of cholesterol and low-density lipoprotein-cholesterol. Moreover, plasma amino acid levels such as alanine (Ala), proline (Pro) and arginine (Arg) were elevated in Gcgr V369M/V369M mice contributing to α-cell proliferation and hyperglucagonemia. Despite sustained α-cell hyperplasia and increased circulating glucagon levels in Gcgr V369M/V369M mice, metabolic disparities between the two groups gradually waned with age accompanied by a reduction in α-cell hyperplasia. Throughout the lifespan of the mice (up to approximately 30 months), pancreatic neuroendocrine tumors (PNETs) did not manifest. This prolonged observation of metabolic alterations in Gcgr V369M/V369M mice furnishes valuable insights for a deeper comprehension of mild Mahvash disease in humans.

Constitutive signal bias mediated by the human GHRHR splice variant 1.

Alternative splicing of G protein-coupled receptors has been observed, but their functions are largely unknown. Here, we report that a splice variant (SV1) of the human growth hormone-releasing hormone receptor (GHRHR) is capable of transducing biased signal. Differing only at the receptor N terminus, GHRHR predominantly activates Gs while SV1 selectively couples to ß-arrestins. Based on the cryogenic electron microscopy structures of SV1 in the apo state or GHRH-bound state in complex with the Gs protein, molecular dynamics simulations reveal that the N termini of GHRHR and SV1 differentiate the downstream signaling pathways, Gs versus ß-arrestins. As suggested by mutagenesis and functional studies, it appears that GHRH-elicited signal bias toward ß-arrestin recruitment is constitutively mediated by SV1. The level of SV1 expression in prostate cancer cells is also positively correlated with ERK1/2 phosphorylation but negatively correlated with cAMP response. Our findings imply that constitutive signal bias may be a mechanism that ensures cancer cell proliferation.

Allosteric Modulators Enhancing GLP-1 Binding to GLP-1R via a Transmembrane Site.

The glucagon-like peptide-1 receptor (GLP-1R) is a well-established drug target for the treatment of type II diabetes. The development of small-molecule positive allosteric modulators (PAMs) of GLP-1R is a promising therapeutic strategy. Here, we report the discovery and characterization of PAMs with distinct chemotypes, binding to a cryptic pocket formed by the cytoplasmic half of TM3, TM5, and TM6. Molecular dynamic simulations and mutagenesis studies indicate that the PAM enlarges the orthosteric pocket to facilitate GLP-1 binding. Further signaling assays characterized their probe-dependent signaling profiles. Our findings provide mechanistic insights into fine-tuning GLP-1R via this allosteric pocket and open up new avenues to design small-molecule drugs for class B G-protein-coupled receptors.

BCL9/BCL9L promotes tumorigenicity through immune-dependent and independent mechanisms in triple negative breast cancer.

Treatment of patients with triple-negative breast cancer (TNBC) has been challenging due to a lack of well-defined molecular targets. The Wnt/ß-catenin pathway is known to be activated in many TNBC patients and BCL9 and BCL9L are important transcriptional co-activators of ß-catenin, but whether inhibition of BCL9/BCL9L can suppress TNBC growth and the underlying mechanism are not fully understood. Here we demonstrate that the expression of BCL9 and BCL9L is directly correlated with malignancy in TNBC patient tumors and that BCL9 and BCL9L promote tumor cell growth, cell migration and metastasis in TNBC models. Mechanistically, we found that BCL9/BCL9L promotes tumorigenicity through both the Wnt and TGF-ß pathways. Besides, BCL9/BCL9L expression inversely correlates with CD8+ T cell infiltration in TNBC and BCL9/BCL9L inhibits the infiltration of CD8+ T cells in the tumor microenvironment. hsBCL9CT-24, an inhibitor of BCL9/ß-catenin peptides, promotes intratumoral infiltration of cytotoxic T cells, reducing regulatory T cells (Treg) and increasing dendritic cells (DCs). Inhibition of BCL9/BCL9L and TGF-ß suppresses activity of Treg. TGF-ß signaling increases tumor infiltration of cytotoxic CD8+ T cells. In accordance, genetic or pharmacological inhibition of BCL9/BCL9L synergizes with PD-1/L1 antibodies to inhibit tumor growth. In summary, these results suggest that targeting BCL9/BCL9L has a direct anti-tumor effect and also unleashes an anti-cancer immune response through inhibition of both Wnt and TGF-ß signaling, suggesting a viable therapeutic approach for TNBC treatment.

W2476 represses TXNIP transcription via dephosphorylation of FOXO1 at Ser319.

Thioredoxin-interacting protein (TXNIP) overexpression is implicated in the pathogenesis of type 2 diabetes. Previous studies have shown that a small molecule compound (W2476) was able to improve ß-cell dysfunction and exert therapeutic effects in diabetic mice via repression of TXNIP signaling pathway. The impact of W2476 on TXNIP transcription was thus investigated using the chromatin immunoprecipitation method. It was found that W2476 promotes competitive binding of forkhead box O1 transcription factor (FOXO1) to the carbohydrate response element (ChoRE) sequence associated with ChoRE-binding protein (ChREBP)/Mlx interacting protein-like(Mlx) complexes. This interaction hinders the attachment of histone acetyltransferase p300 and reduces histone H4 acetylation on the TXNIP promoter, leading to decreasing TXNIP transcription.

The therapeutic potential of attenuated diphtheria toxin delivered by an adenovirus vector with survivin promoter on human lung cancer cells.

Adenoviral vectors are superior to plasmid vectors in their gene transport efficiency. The A subunit of the diphtheria toxin (DTA) gene is a popular suicide gene in cancer gene therapy. However, DTA is seldom used in adenoviral therapy due to its great toxicity. The toxicity of DTA is so great that even a single molecule of DTA is enough to kill one cell. To avoid this highly toxic effect on normal cells, DTA should be controlled by tumor-specific promoters. The survivin promoter is a widely used tumor-specific promoter. But genes driven by the survivin promoter show a low level of basal gene expression in non-cancer cells. DTA driven by the survivin promoter in adenoviral vectors may be highly toxic not only to cancer cells but also to normal cells. Therefore, DTA should be attenuated when it is used in adenoviral vectors driven by the survivin promoter. In this study, we compared the three kinds of recombinant adenoviruses that carry DTA or its attenuated forms (DTA176 and DTA197) in the treatment of human lung cancer. The results showed that in comparison with both DTA and DTA176, DTA197 is more suitable for adenoviral cancer therapy controlled by the survivin promoter. In addition, Adsur-DTA197 (DTA197 delivered by an adenoviral vector with the survivin promoter) sensitized human lung cancer cells to cisplatin both in vitro and in vivo. These results indicated that Adsur-DTA197 may be a potential chemosensitizer in cancer therapy.

Characterization and phylogenetic analysis of the complete mitochondrial genome of a basidiomycetous yeast Cystobasidium sp. (Cystobasidiales: Cystobasidiaceae).

In the present study, the complete mitochondrial genome of a basidiomycetous yeast Cystobasidium sp. was assembled and obtained. The mitochondrial genome of Cystobasidium sp. contains 16 protein-coding genes, 2 ribosomal RNA genes (rRNA), and 24 transfer RNA (tRNA) genes. The complete mitogenome of Cystobasidium sp. has a total length of 24,914 bp, with the base composition as follows: A (30.82), T (32.88%), C (18.37%) and G (17.93%). The Cystobasidium sp. mitogenome exhibited a close relationship with the mitogenome of Microbotryum cf. violaceum, M. lychnidis-dioicae, and Rhodotorula mucilaginosa.

Dopamine D1 receptor agonist treatment alleviates morphine-exposure-induced learning and memory impairments.

We investigated the mechanisms by which the dopamine D1 receptor alleviates morphine-exposure-induced cognitive impairments. Rats were intraperitoneally injected with morphine in a dose-escalating manner over 10 days, and 15 min before the morphine injection on days 1, 3, 5, 7, and 9, the rats were administered the D1 receptor agonist SKF81297 or the D1 receptor antagonist SCH38933 into the midbrain periaqueductal gray (PAG). The Morris water maze was used to examine learning- and memory-related behavioral changes. Midbrain PAG toll-like receptor 4 (TLR4) and protein kinase A (PKA) protein expression was examined using western blot analysis, and cellular expression and localization of TLR4 and PKA were investigated using immunohistochemistry. Chronic morphine exposure impaired spatial learning and memory ability, and resulted in longer latency to the platform, decreased number of platform crossings, and shortened time in the effective area and the target quadrant. Chronic morphine exposure also increased TLR4 and PKA expression in the PAG. However, D1 receptor agonist treatment improved learning and memory ability; in morphine-treated rats, administration of the D1 receptor agonist SKF81297 could shorten the latency to the platform, increase the number of platform crossings, and increase the time spent in the effective area and the target quadrant. In addition, TLR4 expression decreased and PKA expression significantly increased in the PAG in these animals. In summary, administration of the dopamine D1 receptor agonist SKF81297 into the PAG alleviated morphine-exposure-induced cognitive impairments.

Combinatorial antitumor effects of indoleamine 2,3-dioxygenase inhibitor NLG919 and paclitaxel in a murine B16-F10 melanoma model.

Indoleamine 2,3-dioxygenase (IDO) is involved in tumor immune escape and resistance to chemotherapy, and is clinically correlated with tumor progression. IDO inhibitors show marginal efficacy as single agents; therefore, combinations of these inhibitors with other therapies hold promise for cancer therapy. The aim of this study was to investigate the synergistic antitumor effects of IDO inhibitor NLG919 in combination with different regimens of paclitaxel in a murine B16-F10 melanoma model. NLG919 increased the cytotoxic activity of paclitaxel toward B16-F10 cells in the presence of pretreatment with interferon (IFN)-γ in vitro. In B16-F10 tumor-bearing mice, NLG919 was uniformly distributed throughout tumors and decreased kynurenine levels and kynurenine/tryptophan ratios in tumors and plasma for 6-12 h. NLG919 suppressed tumor growth in a dose-dependent manner and exhibited maximum efficacy at 100 mg/kg. In combination with different regimens of paclitaxel, NLG919 displayed synergistic antitumor effects, and NLG919 did not increase the side effects of paclitaxel. Within the tumors, the percentage of CD3+, CD8+, and CD4+ T cells and secretion of IFN-γ and interleukin-2 were synergistically increased, whereas the percentage of CD4+CD25+ regulatory T cells was decreased. NLG919 can potentiate the antitumor efficacy of paclitaxel without increasing its side effects, suggesting that the combination of IDO inhibitor-based immunotherapy with chemotherapy could be a potential strategy for cancer treatment.

Antidepressant-like Effects of LPM580153, A Novel Potent Triple Reuptake Inhibitor.

The purpose of this study was to characterize a novel compound, 4-[2-(dimethylamino)-1-(1-hydroxycyclohexyl) ethyl] phenyl 3-nitrophenyl ether, designated LPM580153. We used several well-validated animal models of depression to assess the antidepressant-like activity of LPM580153, followed by a neurotransmitter uptake assay and a corticosterone-induced cell injury model to explore its mechanism of action. In mice, LPM580153 reduced immobility time in the tail suspension test, and in rats subjected to chronic unpredictable mild stress it reversed reductions in body weight gain and ameliorated anhedonia. The neurotransmitter uptake assay results demonstrated that LPM580153 inhibited the uptake of serotonin, norepinephrine and dopamine. Furthermore, LPM580153 protected the SH-SY5Y cells against the cytotoxic activity of corticosterone, an action that might be related to the role of LPM580153 in increasing the protein levels of BDNF, p-ERK1/2, p-AKT, p-CREB and p-mTOR. Together, these findings indicate that LPM580153 is a novel triple reuptake inhibitor with robust antidepressant-like effects.

RACK1 inhibits morphine re-exposure via inhibition of Src.

OBJECTIVE: We previously demonstrated that receptor for activated C kinase 1 (RACK1) inhibited phosphorylated extracellular signal-regulated kinase (p-ERK) during morphine reward in mice. In the present study, we examined the role of Src in regulating the inhibition of p-ERK in the brain following RACK1 over-expression during morphine reward. METHODS: Mice were subcutaneously injected with morphine on days 2, 4, 6, and 8 after pre-test (day 1), and saline was delivered the following day. After mice showed place preference, RACK1 over-expression plasmid was administered by intraventricular injection 20 minutes after morphine injection on days 11 and 13. Conditioned place preference (CPP) was measured on days 14, 15, 19, and 20. RESULTS: Chronic morphine injection increased Src and p-ERK expression in cortex and hippocampus, and mice exhibited increased place preference. Intraventricular administration of RACK1 reduced Src and p-ERK levels in cortex and hippocampus, as well as morphine reward. At 7 days of final RACK1 administration, the effects of RACK1 on Src and p-ERK disappeared, and morphine place preference was restored. CONCLUSION: We demonstrated that RACK1 acts on ERK activation via Src in morphine reward in mice.

[Production of a monoclonal antibody specific to protoscolex of Echinococcus multilocularis].

OBJECTIVE: To prepare monoclonal antibody (McAb) specific to protoscolex of Echinococcus multilocularis. METHODS: BALB/c mice were immunized with crude antigen derived from E. multilocularis metacestodes. Spleen cells from immunized BALB/c mice were fused with SP2/0 myeloma cells by using hybridoma technique. ELISA and immunohistochemical staining were used to select hybridomas that secreted McAb P325 which especially against protoscolex. The number of metaphase chromosomes of hybridoma cells was counted. Characteristics of McAb P325 were identified by ELISA and immunohistochemical staining. RESULTS: One hybridoma cell clone secreting McAb against protoscolex was obtained. The number of metaphase chromosomes found in hybridoma cells was 98, which showed the characteristics of their parents. Immunohistochemical analysis showed that McAb P325 demonstrated binding activity to the germinal layer and protoscolex of E. multilocularis, especially to the hooklets and suckers, while did not bind with E. granulosus metacestodes and Cysticercus tenuicollis. CONCLUSION: The McAb is a valuable tool for immunohistochemical analysis, cell classification of E. multilocularis protoscolex, and study of specific antigen.