Authors: Wittig JH Jr, Jang AI, Cocjin JB, Inati SK, Zaghloul KA
Journal: Nat Neurosci. 2018 Jun;21(6):808-810. doi: 10.1038/s41593-018-0148-7. Epub 2018 May 21.
We identify a memory-specific attention mechanism in the human anterior temporal lobe, an area implicated in semantic processing and episodic memory formation. Spiking neuron activity is suppressed and becomes more reliable in preparation for verbal memory formation. Intracranial electroencephalography signals implicate this region as a source of executive control for attentional selection. Consistent with this interpretation, its surgical removal causes significant memory impairment for attended words relative to unattended words.
Authors: Zhang J, Chen T, Yang X, Cheng H, Späth SS, Clavijo PE, Chen J, Silvin C, Issaeva N, Su X, Yarbrough WG, Annunziata CM, Chen Z, Van Waes C
Journal: Cancer Res. 2018 Jun 19. pii: canres.0642.2017. doi: 10.1158/0008-5472.CAN-17-0642. [Epub ahead of print]
Human papilloma viruses (HPV) are linked to an epidemic increase in oropharyngeal head and neck squamous cell carcinomas (HNSCC), which display viral inactivation of tumor suppressors TP53 and RB1 and rapid regional spread. However, the role of genomic alterations in enabling modulation of pathways that promote the aggressive phenotype of these cancers is unclear. Recently, a subset of HPV+ HNSCC has been shown to harbor novel genetic defects or decreased expression of TNF-receptor-associated-factor-3 (TRAF3). TRAF3 has been implicated as a negative regulator of alternative NF-κB pathway activation, and activator of anti-viral type-I interferon (IFN) response to other DNA viruses. How TRAF3 alterations affect pathogenesis of HPV+ HNSCC has not been extensively investigated. Here, we report that TRAF3-deficient HPV+ tumors and cell lines exhibit increased expression of alternative NF-κB pathway components and transcription factors NF-κB2/RELB. Overexpression of TRAF3 in HPV+ cell lines with decreased endogenous TRAF3 inhibited NF-κB2/RELB expression, nuclear localization, and NF-κB reporter activity, while increasing the expression of IFNA1 mRNA and protein and sensitizing cells to its growth inhibition. Overexpression of TRAF3 also enhanced TP53 and RB tumor suppressor proteins and decreased HPV E6 oncoprotein in HPV+ cells. Correspondingly, TRAF3 inhibited cell growth, colony formation, migration, and resistance to TNF-α and cisplatin-induced cell death. Conversely, TRAF3 knockout enhanced colony formation and proliferation of an HPV+ HNSCC line expressing higher TRAF3 levels. Together, these findings support a functional role of TRAF3 as a tumor suppressor modulating established cancer hallmarks in HPV+ HNSCC.
Authors: Dantas VGL, Raval MH, Ballesteros A, Cui R, Gunther LK, Yamamoto GL, Alves LU, Bueno AS, Lezirovitz K, Pirana S, Mendes BCA, Yengo CM, Kachar B, Mingroni-Netto RC
Journal: Sci Rep. 2018 Jun 7;8(1):8706. doi: 10.1038/s41598-018-26818-2.
Whole-exome sequencing of samples from affected members of two unrelated families with late-onset non-syndromic hearing loss revealed a novel mutation (c.2090 T > G; NM_017433) in MYO3A. The mutation was confirmed in 36 affected individuals, showing autosomal dominant inheritance. The mutation alters a single residue (L697W or p.Leu697Trp) in the motor domain of the stereocilia protein MYO3A, leading to a reduction in ATPase activity, motility, and an increase in actin affinity. MYO3A-L697W showed reduced filopodial actin protrusion initiation in COS7 cells, and a predominant tipward accumulation at filopodia and stereocilia when coexpressed with wild-type MYO3A and espin-1, an actin-regulatory MYO3A cargo. The combined higher actin affinity and duty ratio of the mutant myosin cause increased retention time at stereocilia tips, resulting in the displacement of the wild-type MYO3A protein, which may impact cargo transport, stereocilia length, and mechanotransduction. The dominant negative effect of the altered myosin function explains the dominant inheritance of deafness.
Authors: Mukaibo T, Munemasa T, Masaki C, Cui CY, Melvin JE
Journal: J Dent Res. 2018 Jun 1:22034518782461. doi: 10.1177/0022034518782461. [Epub ahead of print]
Mutations in the ectodysplasin A gene (EDA) cause X-LHED (X-linked hypohidrotic ectodermal dysplasia), the most common human form of ectodermal dysplasia. Defective EDA signaling is linked to hypoplastic development of epithelial tissues, resulting in hypotrichosis, hypodontia, hypohidrosis, and xerostomia. The primary objective of the present study was to better understand the salivary gland dysfunction associated with ectodermal dysplasia using the analogous murine disorder. The salivary flow rate and ion composition of the 3 major salivary glands were determined in adult Eda-deficient Tabby hemizygous male (Ta/Y) and heterozygous female (Ta/X) mice. Submandibular and sublingual glands of Eda-mutant mice were smaller than wild-type littermates, while parotid gland weight was not significantly altered. Fluid secretion by the 3 major salivary glands was essentially unchanged, but the decrease in submandibular gland size was associated with a dramatic loss of ducts in Ta/Y and Ta/X mice. Reabsorption of Na+ and Cl-, previously linked in salivary glands to Scnn1 Na+ channels and Cftr Cl- channels, respectively, was markedly reduced at high flow rates in the ex vivo submandibular glands of Ta/Y mice (~60%) and, to a lesser extent, Ta/X mice (Na+ by 14%). Consistent with decreased Na+ reabsorption in Ta/Y mice, quantitative polymerase chain reaction analysis detected decreased mRNA expression for Scnn1b and Scnn1g, genes encoding the β and γ subunits, respectively. Moreover, the Na+ channel blocker amiloride significantly inhibited Na+ and Cl- reabsorption by wild-type male submandibular glands to levels comparable to those observed in Ta/Y mice. In summary, fluid secretion was intact in the salivary glands of Eda-deficient mice but displayed marked Na+ and Cl- reabsorption defects that correlated with the loss of duct cells and decreased Scnn1 Na+ channel expression. These results provide a likely mechanism for the elevated NaCl concentration observed in the saliva of affected male and female patients with X-LHED.
Authors: Oh KS, Gottschalk RA, Lounsbury NW, Sun J, Dorrington MG, Baek S, Sun G, Wang Z, Krauss KS, Milner JD, Dutta B, Hager GL, Sung MH, Fraser IDC
Journal: J Immunol. 2018 Jun 13. pii: ji1800158. doi: 10.4049/jimmunol.1800158. [Epub ahead of print]
Macrophage activation by bacterial LPS leads to induction of a complex inflammatory gene program dependent on numerous transcription factor families. The transcription factor Ikaros has been shown to play a critical role in lymphoid cell development and differentiation; however, its function in myeloid cells and innate immune responses is less appreciated. Using comprehensive genomic analysis of Ikaros-dependent transcription, DNA binding, and chromatin accessibility, we describe unexpected dual repressor and activator functions for Ikaros in the LPS response of murine macrophages. Consistent with the described function of Ikaros as transcriptional repressor, Ikzf1-/- macrophages showed enhanced induction for select responses. In contrast, we observed a dramatic defect in expression of many delayed LPS response genes, and chromatin immunoprecipitation sequencing analyses support a key role for Ikaros in sustained NF-κB chromatin binding. Decreased Ikaros expression in Ikzf1+/- mice and human cells dampens these Ikaros-enhanced inflammatory responses, highlighting the importance of quantitative control of Ikaros protein level for its activator function. In the absence of Ikaros, a constitutively open chromatin state was coincident with dysregulation of LPS-induced chromatin remodeling, gene expression, and cytokine responses. Together, our data suggest a central role for Ikaros in coordinating the complex macrophage transcriptional program in response to pathogen challenge.
Authors: Wang Y, Masaki T, Khan SG, Tamura D, Kuschal C, Rogers M, DiGiovanna JJ, Kraemer KH
Journal: PLoS One. 2018 Jun 13;13(6):e0198011. doi: 10.1371/journal.pone.0198011. eCollection 2018.
Recent findings of mosaicism (DNA sequence variation) challenge the dogma that each person has a stable genetic constitution. Copy number variations, point mutations and chromosome abnormalities in normal or diseased tissues have been described. We studied normal skin mosaicism of a single nucleotide polymorphism (SNP) [rs1426654, p.Thr111Ala] in SLC24A5, an ion transporter gene. This SNP is unusual in that more than 90% of people of European descent have homozygous germline A/A alleles, while more than 90% of East Asians and Blacks have homozygous germline G/G alleles. We found mosaicism in neonatal foreskins as well as in 69% of nearly 600 skin surface scraping samples from 114 donors of different ages. Strikingly, donors with germline (buccal or blood) A/A, A/G or G/G genotypes had all three sequences (A/A, A/G or G/G) in the skin surface scrapings. SNP sequence differences extended within the epidermis in the vertical dimension from basal cell layer to the stratum corneum at the surface, as well as across the two-dimensions of the skin surface. Furthermore, repeated scrapings in the same location revealed variation in the sequences in the same individuals over time, adding a fourth dimension to this variation. We then used this mosaicism to track the movement of epidermal cells during normal differentiation and characterize the patterning of epidermal cells during terminal differentiation. In this coordinated proliferation model of epidermal differentiation, the skin surface is alternatively populated by synchronous, cycling of waves of cells, with each group having a different DNA sequence. These groups of cells abruptly flatten into large sheets at the surface providing patches of uniform SNP sequence. This four-dimensional mosaicism is a normal, previously unrecognized form of dynamic mosaicism in human skin.
Authors: Ribeiro JM, Garriga M, Potchen N, Crater AK, Gupta A, Ito D, Desai SA
Journal: Int J Parasitol. 2018 Jun 15. pii: S0020-7519(18)30114-0. doi: 10.1016/j.ijpara.2018.03.009. [Epub ahead of print]
CRISPR-Cas9 mediated genome editing is addressing key limitations in the transfection of malaria parasites. While this method has already simplified the needed molecular cloning and reduced the time required to generate mutants in the human pathogen Plasmodium falciparum, optimal selection of required guide RNAs and guidelines for successful transfections have not been well characterised, leading workers to use time-consuming trial and error approaches. We used a genome-wide computational approach to create a comprehensive and publicly accessible database of possible guide RNA sequences in the P. falciparum genome. For each guide, we report on-target efficiency and specificity scores as well as information about the genomic site relevant to optimal design of CRISPR-Cas9 transfections to modify, disrupt, or conditionally knockdown any gene. As many antimalarial drug and vaccine targets are encoded by multigene families, we also developed a new paralog specificity score that should facilitate modification of either a single family member of interest or multiple paralogs that serve overlapping roles. Finally, we tabulated features of successful transfections in our laboratory, providing broadly useful guidelines for parasite transfections. Molecular studies aimed at understanding parasite biology or characterising drug and vaccine targets in P. falciparum should be facilitated by this comprehensive database.
Authors: Harris ML, Fufa TD, Palmer JW, Joshi SS, Larson DM, Incao A, Gildea DE, Trivedi NS, Lee AN, Day CP, Michael HT, Hornyak TJ, Merlino G; NISC Comparative Sequencing Program, Pavan WJ
Journal: PLoS Biol. 2018 May 3;16(5):e2003648. doi: 10.1371/journal.pbio.2003648. eCollection 2018 May.
Melanocyte stem cells (McSCs) and mouse models of hair graying serve as useful systems to uncover mechanisms involved in stem cell self-renewal and the maintenance of regenerating tissues. Interested in assessing genetic variants that influence McSC maintenance, we found previously that heterozygosity for the melanogenesis associated transcription factor, Mitf, exacerbates McSC differentiation and hair graying in mice that are predisposed for this phenotype. Based on transcriptome and molecular analyses of Mitfmi-vga9/+ mice, we report a novel role for MITF in the regulation of systemic innate immune gene expression. We also demonstrate that the viral mimic poly(I:C) is sufficient to expose genetic susceptibility to hair graying. These observations point to a critical suppressor of innate immunity, the consequences of innate immune dysregulation on pigmentation, both of which may have implications in the autoimmune, depigmenting disease, vitiligo.
Authors: Naz S, Sowers AL, Choudhuri R, Wissler MF, Gamson J, Mathias A, Cook JA, Mitchell JB
Journal: Clin Cancer Res. 2018 May 1. pii: clincanres.3575.2017. doi: 10.1158/1078-0432.CCR-17-3575. [Epub ahead of print]
PURPOSE: To characterize the ionizing radiation (IR) enhancing effects and underlying mechanisms of CDK4/6 inhibitor, Abemaciclib in Non-Small Cell Lung Cancer cells (NSCLC) in vitro and in vivo.
Experimental Design: IR enhancement by Abemaciclib in a variety of NSCLC cell lines was assessed by in vitro clonogenic assay, flow cytometry, and target inhibition verified by immunoblotting. IR-induced DNA damage repair was evaluated by γ-H2AX analysis. Global metabolic alterations by Abemaciclib and IR combination was evaluated by LC/MS mass spectrometry and YSI-Bioanalyzer. Effects of Abemaciclib and IR combination in vivo was studied by xenograft tumor regrowth delay, xenograft lysate immunoblotting, and tissue section immunohistochemistry.
RESULTS: Abemaciclib enhanced the radiosensitivity of NSCLC cells independent of RAS or EGFR status. Enhancement of radiosensitivity was lost in cell lines deficient for functional p53 and RB protein. Post-IR, Abemaciclib treatment inhibited DNA damage repair as measured by γ-H2AX. Mechanistically, Abemaciclib inhibited RB phosphorylation leading to cell cycle arrest. It also inhibited mTOR signaling and reduced intracellular amino acid pool causing nutrient stress. In vivo, Abemaciclib when administered in an adjuvant setting for the second week post-fractionated IR further inhibited vasculogenesis and tumor re-growth with sustained inhibition of RB/E2F activity, mTOR pathway, and HIF-1 expression. In summary, our study signifies inhibiting CDK4/6 pathway by Abemaciclib in combination with IR as a promising therapeutic strategy to treat NSCLC.
CONCLUSIONS: Abemaciclib in combination with IR enhances NSCLC radiosensitivity in preclinical models, potentially providing a novel biomarker driven combination therapeutic strategy for patients with NSCLC.
Authors: Rayn KN, Bloom JB, Gold SA, Hale GR, Baiocco JA, Mehralivand S, Czarniecki M, Sabarwal VK, Valera V, Wood BJ, Merino MJ, Choyke P, Turkbey B, Pinto PA
Journal: J Urol. 2018 May 28. pii: S0022-5347(18)43271-5. doi: 10.1016/j.juro.2018.05.094. [Epub ahead of print]
PURPOSE: We examined the additional value of preoperative prostate multiparametric magnetic resonance imaging (mpMRI) and transrectal ultrasound/mpMRI fusion-guided targeted biopsy (Tbx) when used in combination with clinical nomograms in predicting adverse pathology at radical prostatectomy.
MATERIALS AND METHODS: We identified all patients who underwent 3-Tesla mpMRI prior to fusion biopsy and radical prostatectomy (RP). The Partin and Memorial Sloan Kettering Cancer Center (MSKCC) pre-radical prostatectomy nomograms were used to estimate the probability of organ confined disease (OCD), extraprostatic extension (EPE), seminal vesicle invasion (SVI) and lymph node involvement (LNI) using both transrectal ultrasound-guided systematic biopsy (Sbx) and Tbx Gleason scores. Using RP pathology as a gold standard, we developed multivariable logistic regression models based on these nomograms before and after the addition of mpMRI to assess any additional predictive ability.
RESULTS: 532 patients were included. With the addition of mpMRI findings to the Sbx based MSKCC nomogram, the area under the curve (AUC) increased by 0.10 (p<0.001) for OCD, 0.10 (p=0.003) for EPE, 0.09 (p=0.011) for SVI, and 0.06 (p=0.120) for LNI. Using Gleason Scores derived from Tbx compared to Sbx provided additional predictive value of OCD (ΔAUC=0.07, p=0.003), and EPE (ΔAUC=0.07, p=0.048) on RP with the MSKCC nomogram. Similar results were obtained using the Partin nomogram.
CONCLUSION: MRI alone or in addition to standard clinical nomograms provides significant additional predictive ability of adverse pathology at the time of RP. This information can be greatly beneficial to urologists for preoperative planning and when counseling patients regarding risks of future therapy.