Proceedings of the National Academy of Sciences of the United States of America
Kim, J;Park, D;Seo, NY;Yoon, TH;Kim, GH;Lee, SH;Seo, J;Um, JW;Lee, KJ;Ko, J;
PMID: 35022233 | DOI: 10.1073/pnas.2110196119
Synaptic cell-adhesion molecules (CAMs) organize the architecture and properties of neural circuits. However, whether synaptic CAMs are involved in activity-dependent remodeling of specific neural circuits is incompletely understood. Leucine-rich repeat transmembrane protein 3 (LRRTM3) is required for the excitatory synapse development of hippocampal dentate gyrus (DG) granule neurons. Here, we report that Lrrtm3-deficient mice exhibit selective reductions in excitatory synapse density and synaptic strength in projections involving the medial entorhinal cortex (MEC) and DG granule neurons, accompanied by increased neurotransmitter release and decreased excitability of granule neurons. LRRTM3 deletion significantly reduced excitatory synaptic innervation of hippocampal mossy fibers (Mf) of DG granule neurons onto thorny excrescences in hippocampal CA3 neurons. Moreover, LRRTM3 loss in DG neurons significantly decreased mossy fiber long-term potentiation (Mf-LTP). Remarkably, silencing MEC-DG circuits protected against the decrease in the excitatory synaptic inputs onto DG and CA3 neurons, excitability of DG granule neurons, and Mf-LTP in Lrrtm3-deficient mice. These results suggest that LRRTM3 may be a critical factor in activity-dependent synchronization of the topography of MEC-DG-CA3 excitatory synaptic connections. Collectively, our data propose that LRRTM3 shapes the target-specific structural and functional properties of specific hippocampal circuits.
Cancer immunology research
Ferraccioli, G;Gremese, E;Goletti, D;Petrone, L;Cantini, F;Ugel, S;Canè, S;Bronte, V;
PMID: 35074758 | DOI: 10.1158/2326-6066.CIR-21-0675
Vaccination has been a game changer in our efforts to address the coronavirus disease 2019 (COVID-19) pandemic. However, the disease might still represent a clinical crisis for several more years, in part because of the inevitable emergence of variants capable of evading the pre-existing immunity. Drugs affecting viral spread will help curtail transmission, but therapeutics are needed to treat the more severe cases requiring hospitalization. A deep analysis of the evolving immune landscape of COVID-19 suggests that understanding the molecular bases of the distinct clinical stages is paramount if we are to limit the burden of inflammation, which can lead to death in frail individuals, according to age, sex and comorbidities. Different phases can be defined using immune biomarkers and need specific therapeutic approaches, tailored to the underlying immune contexture.
Tischfield, DJ;Gurevich, A;Johnson, O;Gatmaytan, I;Nadolski, GJ;Soulen, MC;Kaplan, DE;Furth, E;Hunt, SJ;Gade, TPF;
PMID: 35014906 | DOI: 10.1148/radiol.211028
Background Transarterial embolization (TAE) is the most common treatment for hepatocellular carcinoma (HCC); however, there remain limited data describing the influence of TAE on the tumor immune microenvironment. Purpose To characterize TAE-induced modulation of the tumor immune microenvironment in a rat model of HCC and identify factors that modulate this response. Materials and Methods TAE was performed on autochthonous HCCs induced in rats with use of diethylnitrosamine. CD3, CD4, CD8, and FOXP3 lymphocytes, as well as programmed cell death protein ligand-1 (PD-L1) expression, were examined in three cohorts: tumors from rats that did not undergo embolization (control), embolized tumors (target), and nonembolized tumors from rats that had a different target tumor embolized (nontarget). Differences in immune cell recruitment associated with embolic agent type (tris-acryl gelatin microspheres [TAGM] vs hydrogel embolics) and vascular location were examined in rat and human tissues. A generalized estimating equation model and t, Mann-Whitney U, and χ2 tests were used to compare groups. Results Cirrhosis-induced alterations in CD8, CD4, and CD25/CD4 lymphocytes were partially normalized following TAE (CD8: 38.4%, CD4: 57.6%, and CD25/CD4: 21.1% in embolized liver vs 47.7% [P = .02], 47.0% [P = .01], and 34.9% [P = .03], respectively, in cirrhotic liver [36.1%, 59.6%, and 4.6% in normal liver]). Embolized tumors had a greater number of CD3, CD4, and CD8 tumor-infiltrating lymphocytes relative to controls (191.4 cells/mm2 vs 106.7 cells/mm2 [P = .03]; 127.8 cells/mm2 vs 53.8 cells/mm2 [P < .001]; and 131.4 cells/mm2 vs 78.3 cells/mm2 [P = .01]) as well as a higher PD-L1 expression score (4.1 au vs 1.9 au [P < .001]). A greater number of CD3, CD4, and CD8 lymphocytes were found near TAGM versus hydrogel embolics (4.1 vs 2.0 [P = .003]; 3.7 vs 2.0 [P = .01]; and 2.2 vs 1.1 [P = .03], respectively). The number of lymphocytes adjacent to embolics differed based on vascular location (17.9 extravascular CD68+ peri-TAGM cells vs 7.0 intravascular [P < .001]; 6.4 extravascular CD68+ peri-hydrogel embolic cells vs 3.4 intravascular [P < .001]). Conclusion Transarterial embolization-induced dynamic alterations of the tumor immune microenvironment are influenced by underlying liver disease, embolic agent type, and vascular location.
Sheahan, BJ;Theriot, CM;Cortes, JE;Dekaney, CM;
PMID: 35012435 | DOI: 10.1080/19490976.2021.2018898
Acute intestinal mucositis is a common off-target effect of chemotherapy, leading to co-morbidities such as vomiting, diarrhea, sepsis, and death. We previously demonstrated that the presence of enteric bacteria modulates the extent of jejunal epithelial damage induced by doxorubicin (DXR) in mice. Despite conventional thinking of the crypt as a sterile environment, recent evidence suggests that bacterial signaling influences aISC function. In this study, we labeled aISCs using transgenic Lgr5-driven fluorescence or with immunostaining for OLFM4. We examined the effect of DXR in both germ free (GF) mice and mice depleted of microbiota using an established antimicrobial treatment protocol (AMBx). We found differences in DXR-induced loss of aISCs between GF mice and mice treated with AMBx. aISCs were decreased after DXR in GF mice, whereas AMBx mice retained aISC expression after DXR. Neither group of mice exhibited an inflammatory response to DXR, suggesting the difference in aISC retention was not due to differences in local tissue inflammation. Therefore, we suspected that there was a protective microbial signal present in the AMBx mice that was not present in the GF mice. 16S rRNA sequencing of jejunal luminal contents demonstrated that AMBx altered the fecal and jejunal microbiota. In the jejunal contents, AMBx mice had increased abundance of Ureaplasma and Burkholderia. These results suggest pro-survival signaling from microbiota in AMBx-treated mice to the aISCs, and that this signaling maintains aISCs in the face of chemotherapeutic injury. Manipulation of the enteric microbiota presents a therapeutic target for reducing the severity of chemotherapy-associated mucositis.
Hobson, BD;Kong, L;Angelo, MF;Lieberman, OJ;Mosharov, EV;Herzog, E;Sulzer, D;Sims, PA;
PMID: 35021090 | DOI: 10.1016/j.celrep.2021.110208
Midbrain dopaminergic (mDA) neurons exhibit extensive dendritic and axonal arborizations, but local protein synthesis is not characterized in these neurons. Here, we investigate messenger RNA (mRNA) localization and translation in mDA neuronal axons and dendrites, both of which release dopamine (DA). Using highly sensitive ribosome-bound RNA sequencing and imaging approaches, we find no evidence for mRNA translation in mDA axons. In contrast, mDA neuronal dendrites in the substantia nigra pars reticulata (SNr) contain ribosomes and mRNAs encoding the major components of DA synthesis, release, and reuptake machinery. Surprisingly, we also observe dendritic localization of mRNAs encoding synaptic vesicle-related proteins, including those involved in exocytic fusion. Our results are consistent with a role for local translation in the regulation of DA release from dendrites, but not from axons. Our translatome data define a molecular signature of sparse mDA neurons in the SNr, including the enrichment of Atp2a3/SERCA3, an atypical ER calcium pump.
Han, Y;Villarreal-Ponce, A;Gutierrez, G;Nguyen, Q;Sun, P;Wu, T;Sui, B;Berx, G;Brabletz, T;Kessenbrock, K;Zeng, YA;Watanabe, K;Dai, X;
PMID: 35021086 | DOI: 10.1016/j.celrep.2021.110240
Maintenance of undifferentiated, long-lived, and often quiescent stem cells in the basal compartment is important for homeostasis and regeneration of multiple epithelial tissues, but the molecular mechanisms that coordinately control basal cell fate and stem cell quiescence are elusive. Here, we report an epithelium-intrinsic requirement for Zeb1, a core transcriptional inducer of epithelial-to-mesenchymal transition, for mammary epithelial ductal side branching and for basal cell regenerative capacity. Our findings uncover an evolutionarily conserved role of Zeb1 in promoting basal cell fate over luminal differentiation. We show that Zeb1 loss results in increased basal cell proliferation at the expense of quiescence and self-renewal. Moreover, Zeb1 cooperates with YAP to activate Axin2 expression, and inhibition of Wnt signaling partially restores stem cell function to Zeb1-deficient basal cells. Thus, Zeb1 is a transcriptional regulator that maintains both basal cell fate and stem cell quiescence, and it functions in part through suppressing Wnt signaling.
Tiriac, A;Bistrong, K;Pitcher, MN;Tworig, JM;Feller, MB;
PMID: 35021080 | DOI: 10.1016/j.celrep.2021.110225
In mice, retinal direction selectivity is organized in a map that aligns to the body and gravitational axes of optic flow, and little is known about how this map develops. We find direction selectivity maps are largely present at eye opening and develop normally in the absence of visual experience. Remarkably, in mice lacking the beta2 subunit of neuronal nicotinic acetylcholine receptors (β2-nAChR-KO), which exhibit drastically reduced cholinergic retinal waves in the first postnatal week, selectivity to horizontal motion is absent while selectivity to vertical motion remains. We tested several possible mechanisms that could explain the loss of horizontal direction selectivity in β2-nAChR-KO mice (wave propagation bias, FRMD7 expression, starburst amacrine cell morphology), but all were found to be intact when compared with WT mice. This work establishes a role for retinal waves in the development of asymmetric circuitry that mediates retinal direction selectivity via an unknown mechanism.
Alam, MM;Yang, ;Li, XQ;Liu, J;Back, TC;Trivett, A;Karim, B;Barbut, D;Zasloff, M;Oppenheim, JJ;
PMID: 35021075 | DOI: 10.1016/j.celrep.2021.110090
Alpha-synuclein (αS) is causally involved in the development of Parkinson disease (PD); however, its role in normal vertebrate physiology has remained unknown. Recent studies demonstrate that αS is induced by noroviral infection in the enteric nervous system of children and protects mice against lethal neurotropic viral infection. Additionally, αS is a potent chemotactic activator of phagocytes. In this report, using both wild-type and αS knockout mice, we show that αS is a critical mediator of inflammatory and immune responses. αS is required for the development of a normal inflammatory response to bacterial peptidoglycan introduced into the peritoneal cavity as well as antigen-specific and T cell responses following intraperitoneal immunization. Furthermore, we show that neural cells are the sources of αS required for immune competence. Our report supports the hypothesis that αS accumulates within the nervous system of PD individuals because of an inflammatory/immune response.
Cellular and molecular gastroenterology and hepatology
Douchi, D;Yamamura, A;Matsuo, J;Lee, JW;Nuttonmanit, N;Melissa Lim, YH;Suda, K;Shimura, M;Chen, S;Pang, S;Kohu, K;Kaneko, M;Kiyonari, H;Kaneda, A;Yoshida, H;Taniuchi, I;Osato, M;Yang, H;Unno, M;Bok-Yan So, J;Yeoh, KG;Huey Chuang, LS;Bae, SC;Ito, Y;
PMID: 35074568 | DOI: 10.1016/j.jcmgh.2022.01.010
RUNX transcription factors play pivotal roles in embryonic development and neoplasia. We previously identified the single missense mutation R122C in RUNX3 from human gastric cancer. However, how RUNX3R122C mutation disrupts stem cell homeostasis and promotes gastric carcinogenesis remained unclear.To understand the oncogenic nature of this mutation in vivo, we generated the RUNX3R122C knock-in mice. Stomach tissues were harvested, followed by histological and immunofluorescence staining, organoid culture, flow cytometry to isolate gastric corpus isthmus and non-isthmus epithelial cells, and RNA extraction for transcriptomic analysis.The corpus tissue of RUNX3R122C/R122C homozygous mice exhibited a precancerous phenotype such as spasmolytic polypeptide-expressing metaplasia (SPEM). We observed mucous neck cell hyperplasia, massive reduction of pit, parietal, and chief cell populations, as well as a dramatic increase in the number of rapidly proliferating isthmus stem/progenitor cells in the corpus of RUNX3R122C/R122C mice. Transcriptomic analyses of the isolated epithelial cells showed that the cell cycle-related MYC target gene signature was enriched in the corpus epithelial cells of RUNX3R122C/R122C mice compared with the wild-type corpus. Mechanistically, RUNX3R122C mutant protein disrupted the regulation of the restriction point where cells decide to enter either proliferative or quiescent state, thereby driving stem cell expansion and limiting the ability of cells to terminally differentiate.RUNX3R122C missense mutation is associated with the continuous cycling of isthmus stem/progenitor cells, maturation arrest and development of a precancerous state. This work highlights the importance of RUNX3 in prevention of metaplasia and gastric cancer.
Circulation. Heart failure
Verma, AK;Olagoke, O;Moreno, JD;Rezaee, N;Ma, P;Liu, J;Javaheri, A;Lavine, K;Masood, MF;Lin, CY;
PMID: 35012323 | DOI: 10.1161/CIRCHEARTFAILURE.120.008273
Metabolism: clinical and experimental
Perdices-Lopez, C;Avendaño, MS;Barroso, A;Gaytán, F;Ruiz-Pino, F;Vázquez, MJ;Leon, S;Song, YB;Sobrino, V;Heras, V;Romero-Ruiz, A;Roa, J;Mayor, F;Murga, C;Pinilla, L;Kaiser, UB;Tena-Sempere, M;
PMID: 35074314 | DOI: 10.1016/j.metabol.2022.155141
Perturbations in the timing of puberty, with potential adverse consequences in later health, are increasingly common. The underlying neurohormonal mechanisms are unfolded, but nutritional alterations are key contributors. Efforts to unveil the basis of normal puberty and its metabolic control have focused on mechanisms controlling expression of Kiss1, the gene encoding the puberty-activating neuropeptide, kisspeptin. However, other regulatory phenomena remain ill-defined. Here, we address the putative role of the G protein-coupled-receptor kinase-2, GRK2, in GnRH neurons, as modulator of pubertal timing via repression of the actions of kisspeptin, in normal maturation and conditions of nutritional deficiency.Hypothalamic RNA and protein expression analyses were conducted in maturing female rats. Pharmacological studies involved central administration of GRK2 inhibitor, βARK1-I, and assessment of gonadotropin responses to kisspeptin or phenotypic and hormonal markers of puberty, under normal nutrition or early subnutrition in female rats. In addition, a mouse line with selective ablation of GRK2 in GnRH neurons, aka G-GRKO, was generated, in which hormonal responses to kisspeptin and puberty onset were monitored, in normal conditions and after nutritional deprivation.Hypothalamic GRK2 expression increased along postnatal maturation in female rats, especially in the preoptic area, where most GnRH neurons reside, but decreased during the juvenile-to-pubertal transition. Blockade of GRK2 activity enhanced Ca+2 responses to kisspeptin in vitro, while central inhibition of GRK2 in vivo augmented gonadotropin responses to kisspeptin and advanced puberty onset. Postnatal undernutrition increased hypothalamic GRK2 expression and delayed puberty onset, the latter being partially reversed by central GRK2 inhibition. Conditional ablation of GRK2 in GnRH neurons enhanced gonadotropin responses to kisspeptin, accelerated puberty onset, and increased LH pulse frequency, while partially prevented the negative impact of subnutrition on pubertal timing and LH pulsatility in mice.Our data disclose a novel pathway whereby GRK2 negatively regulates kisspeptin actions in GnRH neurons, as major regulatory mechanism for tuning pubertal timing in nutritionally-compromised conditions.
Metabolism: clinical and experimental
González-García, I;Freire-Agulleiro, Ó;Nakaya, N;Ortega, FJ;Garrido-Gil, P;Liñares-Pose, L;Fernø, J;Labandeira-Garcia, JL;Diéguez, C;Sultana, A;Tomarev, SI;Fernández-Real, JM;López, M;
PMID: 35026233 | DOI: 10.1016/j.metabol.2021.155122
Olfactomedin 2 (OLFM2; also known as noelin 2) is a pleiotropic protein that plays a major role in olfaction and Olfm2 null mice exhibit reduced olfactory sensitivity, as well as abnormal motor coordination and anxiety-related behavior. Here, we investigated the possible metabolic role of OLFM2.Olfm2 null mice were metabolically phenotyped. Virogenetic modulation of central OLFM2 was also performed.Our data showed that, the global lack of OLFM2 in mice promoted anorexia and increased energy expenditure due to elevated brown adipose tissue (BAT) thermogenesis and browning of white adipose tissue (WAT). This phenotype led to resistance to high fat diet (HFD)-induced obesity. Notably, virogenetic overexpression of Olfm2 in the lateral hypothalamic area (LHA) induced weight gain associated with decreased BAT thermogenesis.Overall, this evidence first identifies central OLFM2 as a new molecular actor in the regulation of whole-body energy homeostasis.