Development (Cambridge, England)
Iwayama, T;Iwashita, M;Miyashita, K;Sakashita, H;Matsumoto, S;Tomita, K;Bhongsatiern, P;Kitayama, T;Ikegami, K;Shimbo, T;Tamai, K;Murayama, MA;Ogawa, S;Iwakura, Y;Yamada, S;Olson, LE;Takedachi, M;Murakami, S;
PMID: 36245218 | DOI: 10.1242/dev.201203
Periodontal tissue supports teeth in the alveolar bone socket via fibrous attachment of the periodontal ligament (PDL). The PDL contains periodontal fibroblasts and stem/progenitor cells, collectively known as PDL cells (PDLCs), on top of osteoblasts and cementoblasts on the surface of alveolar bone and cementum, respectively. However, the characteristics and lineage hierarchy of each cell type remain poorly defined. This study identified periodontal ligament associated protein-1 (Plap-1) as a PDL-specific extracellular matrix protein. We generated knock-in mice expressing CreERT2 and GFP specifically in Plap-1-positive PDLCs. Genetic lineage tracing confirmed the long-standing hypothesis that PDLCs differentiate into osteoblasts and cementoblasts. A PDL single-cell atlas defined cementoblasts and osteoblasts as Plap-1-Ibsp+Sparcl1+ and Plap-1-Ibsp+Col11a2+, respectively. Other populations, such as Nes+ mural cells, S100B+ Schwann cells, and other non-stromal cells, were also identified. RNA velocity analysis suggested that a Plap-1highLy6a+ cell population was the source of PDLCs. Lineage tracing of Plap-1+ PDLCs during periodontal injury showed periodontal tissue regeneration by PDLCs. Our study defines diverse cell populations in PDL and clarifies the role of PDLCs in periodontal tissue homeostasis and repair.
Peach, CJ;Edgington-Mitchell, LE;Bunnett, NW;Schmidt, BL;
PMID: 35901239 | DOI: 10.1152/physrev.00044.2021
Although generally regarded as degradatory enzymes, certain proteases are also signaling molecules that specifically control cellular functions by cleaving protease-activated receptors (PARs). The four known PARs are members of the large family of G protein-coupled receptors. These transmembrane receptors control most physiological and pathological processes and are the target of a large proportion of therapeutic drugs. Signaling proteases include enzymes from the circulation, from immune, inflammatory epithelial and cancer cells, as well as from commensal and pathogenic bacteria. Advances in our understanding of the structure and function of PARs provide insights into how diverse proteases activate these receptors to regulate physiological and pathological processes in most tissues and organ systems. The realization that proteases and PARs are key mediators of disease, coupled with advances in understanding the atomic level structure of PARs and their mechanisms of signaling in subcellular microdomains, has spurred the development of antagonists, some of which have advanced to the clinic. Herein we review the discovery, structure and function of this receptor system, highlight the contribution of PARs to homeostatic control, and discuss the potential of PAR antagonists for the treatment of major diseases.
Uapinyoying, P;Hogarth, M;Battacharya, S;Mázala, D;Panchapakesan, K;Bonnemann, C;Jaiswal, J;
| DOI: 10.2139/ssrn.4120770
Fibro/adipogenic progenitors (FAPs) are skeletal muscle stromal cells that support regeneration of injured myofibers and their maintenance in healthy muscles. FAPs are related to mesenchymal stem cells (MeSCs) found in other adult tissues, but there is poor understanding of the extent of similarity between these cells. Using single cell RNA sequencing (scRNA-seq) datasets from multiple mouse tissues we have performed comparative transcriptomic analysis between these cells. This identified remarkable transcriptional similarity between FAPs and MeSCs and confirmed the suitability of PDGFRα as a reliable reporter for FAPs. It also identified extracellular proteolysis as a new function of FAPs. Using PDGFRα as a cell surface marker, we isolated FAPs from healthy and dysferlinopathic mouse muscles and performed scRNA-seq analysis. This identified decreased FAP-mediated Wnt signaling as a potential driver of FAP dysfunction in dysferlinopathic muscles. Analysis of FAPs in dysferlin- and dystrophindeficient muscles identified distinct FAP-specific gene expression changes between these diseases that show existence of reciprocal relationship between muscle pathology and FAP gene expression.
Proceedings of the National Academy of Sciences of the United States of America
Rodriguez-Hernandez, CJ;Sokoloski, KJ;Stocke, KS;Dukka, H;Jin, S;Metzler, MA;Zaitsev, K;Shpak, B;Shen, D;Miller, DP;Artyomov, MN;Lamont, RJ;Bagaitkar, J;
PMID: 34921113 | DOI: 10.1073/pnas.2105170118
Here, we show that Porphyromonas gingivalis (Pg), an endogenous oral pathogen, dampens all aspects of interferon (IFN) signaling in a manner that is strikingly similar to IFN suppression employed by multiple viral pathogens. Pg suppressed IFN production by down-regulating several IFN regulatory factors (IRFs 1, 3, 7, and 9), proteolytically degrading STAT1 and suppressing the nuclear translocation of the ISGF3 complex, resulting in profound and systemic repression of multiple interferon-stimulated genes. Pg-induced IFN paralysis was not limited to murine models but was also observed in the oral tissues of human periodontal disease patients, where overabundance of Pg correlated with suppressed IFN generation. Mechanistically, multiple virulence factors and secreted proteases produced by Pg transcriptionally suppressed IFN promoters and also cleaved IFN receptors, making cells refractory to exogenous IFN and inducing a state of broad IFN paralysis. Thus, our data show a bacterial pathogen with equivalence to viruses in the down-regulation of host IFN signaling.
Lee, SH;Rezzonico, MG;Friedman, BA;Huntley, MH;Meilandt, WJ;Pandey, S;Chen, YJ;Easton, A;Modrusan, Z;Hansen, DV;Sheng, M;Bohlen, CJ;
PMID: 34965428 | DOI: 10.1016/j.celrep.2021.110158
Non-neuronal responses in neurodegenerative disease have received increasing attention as important contributors to disease pathogenesis and progression. Here we utilize single-cell RNA sequencing to broadly profile 13 cell types in three different mouse models of Alzheimer disease (AD), capturing the effects of tau-only, amyloid-only, or combined tau-amyloid pathology. We highlight microglia, oligodendrocyte, astrocyte, and T cell responses and compare them across these models. Notably, we identify two distinct transcriptional states for oligodendrocytes emerging differentially across disease models, and we determine their spatial distribution. Furthermore, we explore the impact of Trem2 deletion in the context of combined pathology. Trem2 knockout mice exhibit severely blunted microglial responses to combined tau and amyloid pathology, but responses from non-microglial cell types (oligodendrocytes, astrocytes, and T cells) are relatively unchanged. These results delineate core transcriptional states that are engaged in response to AD pathology, and how they are influenced by a key AD risk gene, Trem2.
Jensen, NK;Ingvorsen, C;Petersen, DR;Pereira, MJ;Lu, TTH;Alsted, TJ;Kirkegaard, JS;Keane, KA;
PMID: 34555946 | DOI: 10.1177/01926233211036395
Islet-like clusters derived from human embryonic stem cells (hESC) hold the potential to cure type 1 diabetes mellitus. Differentiation protocols of islet-like clusters lead to the generation of minor fractions of nonendocrine cells, which are mainly from endodermal and mesodermal lineages, and the risk of implanting these is unclear. In the present study, the histogenesis and the tumorigenicity of nonendocrine cells were investigated in vivo. Immunodeficient mice were implanted under the kidney capsule with islet-like clusters which were derived from differentiation of cells batches with either an intermediate or poor cell purity and followed for 8 or 26 weeks. Using immunohistochemistry and other techniques, it was found that the intermediate differentiated cell implants had limited numbers of small duct-like cysts and nonpancreatic tissue resembling gastrointestinal and retinal pigmented epithelium. In contrast, highly proliferative cystic teratomas were found at a high incidence at the implant site after 8 weeks, only in the animals implanted with the poorly differentiated cells. These findings indicate that the risk for teratoma formation and the amount of nonpancreatic tissue can be minimized by careful in-process characterization of the cells and thus highlights the importance of high purity at transplantation and a thorough ex-vivo characterization during cell product development.
Single-nucleus transcriptome analysis reveals cell-type-specific molecular signatures across reward circuitry in the human brain
Tran, MN;Maynard, KR;Spangler, A;Huuki, LA;Montgomery, KD;Sadashivaiah, V;Tippani, M;Barry, BK;Hancock, DB;Hicks, SC;Kleinman, JE;Hyde, TM;Collado-Torres, L;Jaffe, AE;Martinowich, K;
PMID: 34582785 | DOI: 10.1016/j.neuron.2021.09.001
Single-cell gene expression technologies are powerful tools to study cell types in the human brain, but efforts have largely focused on cortical brain regions. We therefore created a single-nucleus RNA-sequencing resource of 70,615 high-quality nuclei to generate a molecular taxonomy of cell types across five human brain regions that serve as key nodes of the human brain reward circuitry: nucleus accumbens, amygdala, subgenual anterior cingulate cortex, hippocampus, and dorsolateral prefrontal cortex. We first identified novel subpopulations of interneurons and medium spiny neurons (MSNs) in the nucleus accumbens and further characterized robust GABAergic inhibitory cell populations in the amygdala. Joint analyses across the 107 reported cell classes revealed cell-type substructure and unique patterns of transcriptomic dynamics. We identified discrete subpopulations of D1- and D2-expressing MSNs in the nucleus accumbens to which we mapped cell-type-specific enrichment for genetic risk associated with both psychiatric disease and addiction.
Shifting Gears in Precision Oncology-Challenges and Opportunities of Integrative Data Analysis
Noh, KW;Buettner, R;Klein, S;
PMID: 34572523 | DOI: 10.3390/biom11091310
For decades, research relating to modification of host immunity towards antitumor response activation has been ongoing, with the breakthrough discovery of immune-checkpoint blockers. Several biomarkers with potential predictive value have been reported in recent studies for these novel therapies. However, with the plethora of therapeutic options existing for a given cancer entity, modern oncology is now being confronted with multifactorial interpretation to devise "the best therapy" for the individual patient. Into the bargain come the multiverse guidelines for established and emerging diagnostic biomarkers, as well as the complex interplay between cancer cells and tumor microenvironment, provoking immense challenges in the therapy decision-making process. Through this review, we present various molecular diagnostic modalities and techniques, such as genomics, immunohistochemistry and quantitative image analysis, which have the potential of becoming powerful tools in the development of an optimal treatment regime when analogized with patient characteristics. We will summarize the underlying complexities of these methods and shed light upon the necessary considerations and requirements for data integration. It is our hope to provide compelling evidence to emphasize on the need for inclusion of integrative data analysis in modern cancer therapy, and thereupon paving a path towards precision medicine and better patient outcomes.
Anterior thalamic dysfunction underlies cognitive deficits in a subset of neuropsychiatric disease models
Roy, DS;Zhang, Y;Aida, T;Choi, S;Chen, Q;Hou, Y;Lea, NE;Skaggs, KM;Quay, JC;Liew, M;Maisano, H;Le, V;Jones, C;Xu, J;Kong, D;Sullivan, HA;Saunders, A;McCarroll, SA;Wickersham, IR;Feng, G;
PMID: 34197733 | DOI: 10.1016/j.neuron.2021.06.005
Neuropsychiatric disorders are often accompanied by cognitive impairments/intellectual disability (ID). It is not clear whether there are converging mechanisms underlying these debilitating impairments. We found that many autism and schizophrenia risk genes are expressed in the anterodorsal subdivision (AD) of anterior thalamic nuclei, which has reciprocal connectivity with learning and memory structures. CRISPR-Cas9 knockdown of multiple risk genes selectively in AD thalamus led to memory deficits. While the AD is necessary for contextual memory encoding, the neighboring anteroventral subdivision (AV) regulates memory specificity. These distinct functions of AD and AV are mediated through their projections to retrosplenial cortex, using differential mechanisms. Furthermore, knockdown of autism and schizophrenia risk genes PTCHD1, YWHAG, or HERC1 from AD led to neuronal hyperexcitability, and normalization of hyperexcitability rescued memory deficits in these models. This study identifies converging cellular to circuit mechanisms underlying cognitive deficits in a subset of neuropsychiatric disease models.
Enkephalin release from VIP interneurons in the hippocampal CA2/3a region mediates heterosynaptic plasticity and social memory
Leroy, F;de Solis, CA;Boyle, LM;Bock, T;Lofaro, OM;Buss, EW;Asok, A;Kandel, ER;Siegelbaum, SA;
PMID: 33990774 | DOI: 10.1038/s41380-021-01124-y
The hippocampus contains a diverse array of inhibitory interneurons that gate information flow through local cortico-hippocampal circuits to regulate memory storage. Although most studies of interneurons have focused on their role in fast synaptic inhibition mediated by GABA release, different classes of interneurons express unique sets of neuropeptides, many of which have been shown to exert powerful effects on neuronal function and memory when applied pharmacologically. However, relatively little is known about whether and how release of endogenous neuropeptides from inhibitory cells contributes to their behavioral role in regulating memory formation. Here we report that vasoactive intestinal peptide (VIP)-expressing interneurons participate in social memory storage by enhancing information transfer from hippocampal CA3 pyramidal neurons to CA2 pyramidal neurons. Notably, this action depends on release of the neuropeptide enkephalin from VIP neurons, causing long-term depression of feedforward inhibition onto CA2 pyramidal cells. Moreover, VIP neuron activity in the CA2 region is increased selectively during exploration of a novel conspecific. Our findings, thus, enhance our appreciation of how GABAergic neurons can regulate synaptic plasticity and mnemonic behavior by demonstrating that such actions can be mediated by release of a specific neuropeptide, rather than through classic fast inhibitory transmission.
Post-mortem molecular investigations of SARS-CoV-2 in an unexpected death of a recent kidney transplant recipient
American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons
Simms, EL;Chung, H;Oberding, L;Muruve, D;McDonald, B;Bromley, A;Pillai, DR;Chun, J;
PMID: 33624432 | DOI: 10.1111/ajt.16549
Solid organ transplant recipients are vulnerable to severe infection during induction therapy. We report a case of a 67-year-old male who died unexpectedly 10 days after receiving a kidney transplant on February 10, 2020. There was no clear cause of death, but COVID-19 was considered retrospectively, as the death occurred shortly after the first confirmed case of COVID-19 in Canada. We confirmed the presence of SARS-CoV-2 components in the renal allograft and native lung tissue using immunohistochemistry for SARS-CoV-2 spike protein and RNA scope in situ hybridization for SARS-CoV-2 RNA. Results were reaffirmed with the Food and Drug Administration Emergency Use Authorization approved Bio-Rad SARS-CoV-2 digital droplet PCR for the kidney specimen. Our case highlights the importance of patient autopsies in an unfolding global pandemic and demonstrates the utility of molecular assays to diagnose SARS-CoV-2 post-mortem. SARS-CoV-2 infection during induction therapy may portend a fatal clinical outcome. We also suggest COVID-19 may be transmittable via renal transplant. This article is protected by
IGF2R circular RNA hsa_circ_0131235 expression in the middle temporal cortex is associated with AD pathology
Bigarré, IM;Trombetta, BA;Guo, YJ;Arnold, SE;Carlyle, BC;
PMID: 33704916 | DOI: 10.1002/brb3.2048
To identify circular RNAs as candidates for differential expression in the middle temporal (MT) cortex in a well-characterized cohort with contrasting Alzheimer disease (AD) pathology and cognition. Top screen candidates were assessed for proof of circularity and then quantified by qPCR in a larger number of samples. An initial RNA sequencing screen was performed on n = 20 frozen human tissue samples. Filters were applied to select candidate circular RNAs for further investigation. Frozen human tissue samples were selected for global AD pathology burden and global cognition scores (n = 100). Linear and divergent primers were used to assess circularity using RNaseR digestion. RT-qPCR was performed to quantify relative hsa_circ_0131235 abundance. Eleven circular RNAs were selected for further investigation. Four candidates produced circular RNA primers with appropriate efficiencies for qPCR. RNaseR treatment and analysis by both basic PCR and qPCR confirmed hsa_circ_0131235 circularity. There was a significant main effect of AD pathology on hsa_circ_0131235 expression. Elevated hsa_circ_0131235 expression in the MT cortex was significantly associated with AD pathology.