Probes for INS

G-protein-coupled receptors (GPCRs) mediate neuromodulation through the activation of heterotrimeric G proteins (Gαβγ). Classical models depict that G protein activation leads to a one-to-one formation of Gα-GTP and Gβγ species. Each of these species propagates signaling by independently acting on effectors, but the mechanisms by which response fidelity is ensured by coordinating Gα and Gβγ responses remain unknown. Here, we reveal a paradigm of G protein regulation whereby the neuronal protein GINIP (Gα inhibitory interacting protein) biases inhibitory GPCR responses to favor Gβγ over Gα signaling. Tight binding of GINIP to Gαi-GTP precludes its association with effectors (adenylyl cyclase) and, simultaneously, with regulator-of-G-protein-signaling (RGS) proteins that accelerate deactivation. As a consequence, Gαi-GTP signaling is dampened, whereas Gβγ signaling is enhanced. We show that this mechanism is essential to prevent the imbalances of neurotransmission that underlie increased seizure susceptibility in mice. Our findings reveal an additional layer of regulation within a quintessential mechanism of signal transduction that sets the tone of neurotransmission.

Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma has unique biology and better outcomes. p16 immunostaining is used as a surrogate marker for transcriptionally active HPV. Although diffuse staining is generally accepted as positive, the significance of partial staining has not been established, nor has the cutoff for extent of p16 staining that should be used to identify a tumor as HPV-related. From three other large studies utilizing p16 immunohistochemistry, we identified all cases with partial positive staining. The p16-stained slides were reviewed by three study pathologists for staining (nuclear and cytoplasmic) extent (in quartiles), and also for percentage that was confluent (ie, back-to-back cell staining). Tumors were histologically typed (keratinizing, non-keratinizing, or non-keratinizing with maturation) and tested for high-risk HPV by RNA in-situ hybridization and reverse-transcriptase PCR. For the 16 cases, there were two 4+(13%), five 3+(31%), six 2+(38%), and three 1+(19%) p16 staining tumors. Extent of staining ranged from 5 to 90% of cells positive with 25% or more confluent staining in 4/16 (25%). Of the 16 (31%) cases, 5 were HPV-related on the basis of RNA in-situ hybridization and reverse-transcriptase PCR. All of these cases had >50% p16 staining, 4/5 (80%) had more than 25% confluent staining, and 4/7 (57%) had non-keratinizing histological features. Only one of the p16 1+/2+ tumors was HPV RNA-positive (by reverse-transcriptase PCR only and low level). All 1+/2+ cases were keratinizing type or undifferentiated. By sensitive detection methods, most partial p16-positive squamous cell carcinoma cases with >50% staining harbor transcriptionally active HPV, and most HPV+ tumors have significant amounts of confluent staining. Cases with <50% p16 staining and lacking significant confluent staining rarely harbor HPV. These results support that greater than 75% p16 staining or, alternatively, >50% staining combined with >25% confluent areas, are suitable cutoffs for defining positivity.

The differential diagnosis of intrahepatic cholangiocarcinomas (iCCAs) from metastatic adenocarcinomas from organs adjacent to the liver (gallbladder, pancreas, and stomach) is difficult due to histopathological similarity and a lack of specific markers. This study aimed to develop a method to differentiate iCCA and adenocarcinomas originated from extrahepatic organs adjacent to the liver.We retrospectively enrolled surgically resected iCCA (n = 181) and adenocarcinomas from extrahepatic organs (n = 30, n = 28, and n = 38 from gallbladder, pancreas, and stomach, respectively) between 2007 and 2013. The albumin mRNA in situ hybridization (ISH) and immunohistochemistry (IHC) of filamin-A and cytokeratin 19 (CK19) were performed using tissue microarray. Using logistic regression analysis of three markers, iCCA-score was developed, and its diagnostic performance was evaluated.The iCCAs were more frequently positive for albumin ISH (23.2% vs. 0%), filamin-A IHC (47.5% vs. 12.5%) and CK19 (68.5% vs. 40.6%) than extrahepatic adenocarcinomas (p < 0.001 for all). The iCCA-score consisting of these three markers was developed, and it showed higher diagnostic performance (area under the curve [AUC], 0.798 vs. 0.616, p < 0.001). Taking an iCCA-score of 2 or higher as the threshold for iCCA, the sensitivity was substantially higher than albumin ISH alone (45.9% and 23.2%, respectively; p < 0.001), but maintained high specificity (94.8% and 100%, respectively).Albumin ISH and IHC staining for filamin-A and CK19 showed distinct expression patterns between iCCA and extrahepatic adenocarcinomas from gallbladder, pancreas, and stomach. We developed iCCA-score that consisted of those three markers, and it showed better diagnostic performance than albumin ISH alone.