-
Molecular Therapy : the Journal of the... Sep 2021Non-human primates (NHPs) are a preferred animal model for optimizing adeno-associated virus (AAV)-mediated CNS gene delivery protocols before clinical trials. In spite...
Non-human primates (NHPs) are a preferred animal model for optimizing adeno-associated virus (AAV)-mediated CNS gene delivery protocols before clinical trials. In spite of its inherent appeal, it is challenging to compare different serotypes, delivery routes, and disease indications in a well-powered, comprehensive, multigroup NHP experiment. Here, a multiplex barcode recombinant AAV (rAAV) vector-tracing strategy has been applied to a systemic analysis of 29 distinct, wild-type (WT), AAV natural isolates and engineered capsids in the CNS of eight macaques. The report describes distribution of each capsid in 15 areas of the macaques' CNS after intraparenchymal (putamen) injection, or cerebrospinal fluid (CSF)-mediated administration routes (intracisternal, intrathecal, or intracerebroventricular). To trace the vector biodistribution (viral DNA) and targeted tissues transduction (viral mRNA) of each capsid in each of the analyzed CNS areas, quantitative next-generation sequencing analysis, assisted by the digital-droplet PCR technology, was used. The report describes the most efficient AAV capsid variants targeting specific CNS areas after each route of administration using the direct side-by-side comparison of WT AAV isolates and a new generation of rationally designed capsids. The newly developed bioinformatics and visualization algorithms, applicable to the comparative analysis of several mammalian brain models, have been developed and made available in the public domain.
Topics: Algorithms; Animals; Capsid Proteins; Central Nervous System; DNA, Viral; Databases, Genetic; Dependovirus; Drug Administration Routes; Genetic Vectors; High-Throughput Nucleotide Sequencing; Primates; RNA, Messenger; RNA, Viral; Tissue Distribution; Transduction, Genetic
PubMed: 34298128
DOI: 10.1016/j.ymthe.2021.07.010 -
Cellular and Molecular Life Sciences :... Nov 2008Up to 10% of the mouse genome is comprised of endogenous retrovirus (ERV) sequences, and most represent the remains of ancient germ line infections. Our knowledge of the... (Review)
Review
Up to 10% of the mouse genome is comprised of endogenous retrovirus (ERV) sequences, and most represent the remains of ancient germ line infections. Our knowledge of the three distinct classes of ERVs is inversely correlated with their copy number, and their characterization has benefited from the availability of divergent wild mouse species and subspecies, and from ongoing analysis of the Mus genome sequence. In contrast to human ERVs, which are nearly all extinct, active mouse ERVs can still be found in all three ERV classes. The distribution and diversity of ERVs has been shaped by host-virus interactions over the course of evolution, but ERVs have also been pivotal in shaping the mouse genome by altering host genes through insertional mutagenesis, by adding novel regulatory and coding sequences, and by their co-option by host cells as retroviral resistance genes. We review mechanisms by which an adaptive coexistence has evolved. (Part of a multi-author review).
Topics: Amino Acid Sequence; Animals; Endogenous Retroviruses; Evolution, Molecular; Gammaretrovirus; Gene Transfer, Horizontal; Genes, Intracisternal A-Particle; Genome; Host-Pathogen Interactions; Humans; Membrane Glycoproteins; Mice; Models, Biological; Molecular Sequence Data; Mutagenesis, Insertional; Neoplasms; Receptors, Virus; Retroelements; Retroviridae Infections; Retroviridae Proteins; Rodent Diseases; Tumor Virus Infections; Vertebrates
PubMed: 18818872
DOI: 10.1007/s00018-008-8497-0 -
Cell Reports Jun 2023Endogenous retroviruses (ERVs) have rewired host gene networks. To explore the origins of co-option, we employed an active murine ERV, IAPEz, and an embryonic stem cell...
Endogenous retroviruses (ERVs) have rewired host gene networks. To explore the origins of co-option, we employed an active murine ERV, IAPEz, and an embryonic stem cell (ESC) to neural progenitor cell (NPC) differentiation model. Transcriptional silencing via TRIM28 maps to a 190 bp sequence encoding the intracisternal A-type particle (IAP) signal peptide, which confers retrotransposition activity. A subset of "escapee" IAPs (∼15%) exhibits significant genetic divergence from this sequence. Canonical repressed IAPs succumb to a previously undocumented demarcation by H3K9me3 and H3K27me3 in NPCs. Escapee IAPs, in contrast, evade repression in both cell types, resulting in their transcriptional derepression, particularly in NPCs. We validate the enhancer function of a 47 bp sequence within the U3 region of the long terminal repeat (LTR) and show that escapee IAPs convey an activating effect on nearby neural genes. In sum, co-opted ERVs stem from genetic escapees that have lost vital sequences required for both TRIM28 restriction and autonomous retrotransposition.
Topics: Animals; Mice; Cell Differentiation; Embryonic Stem Cells; Endogenous Retroviruses; Histones; Tripartite Motif-Containing Protein 28; Terminal Repeat Sequences
PubMed: 37294634
DOI: 10.1016/j.celrep.2023.112625 -
Nature Aug 2020In mammals, the acquisition of the germline from the soma provides the germline with an essential challenge: the need to erase and reset genomic methylation. In the male...
In mammals, the acquisition of the germline from the soma provides the germline with an essential challenge: the need to erase and reset genomic methylation. In the male germline, RNA-directed DNA methylation silences young, active transposable elements. The PIWI protein MIWI2 (PIWIL4) and its associated PIWI-interacting RNAs (piRNAs) instruct DNA methylation of transposable elements. piRNAs are proposed to tether MIWI2 to nascent transposable element transcripts; however, the mechanism by which MIWI2 directs the de novo methylation of transposable elements is poorly understood, although central to the immortality of the germline. Here we define the interactome of MIWI2 in mouse fetal gonocytes undergoing de novo genome methylation and identify a previously unknown MIWI2-associated factor, SPOCD1, that is essential for the methylation and silencing of young transposable elements. The loss of Spocd1 in mice results in male-specific infertility but does not affect either piRNA biogenesis or the localization of MIWI2 to the nucleus. SPOCD1 is a nuclear protein whose expression is restricted to the period of de novo genome methylation. It co-purifies in vivo with DNMT3L and DNMT3A, components of the de novo methylation machinery, as well as with constituents of the NURD and BAF chromatin remodelling complexes. We propose a model whereby tethering of MIWI2 to a nascent transposable element transcript recruits repressive chromatin remodelling activities and the de novo methylation apparatus through SPOCD1. In summary, we have identified a previously unrecognized and essential executor of mammalian piRNA-directed DNA methylation.
Topics: Animals; Argonaute Proteins; Chromatin Assembly and Disassembly; DNA (Cytosine-5-)-Methyltransferases; DNA Methylation; DNA Methyltransferase 3A; DNA Transposable Elements; Female; Fertility; Gene Silencing; Genes, Intracisternal A-Particle; Long Interspersed Nucleotide Elements; Male; Mice; RNA, Small Interfering; Spermatogenesis
PubMed: 32674113
DOI: 10.1038/s41586-020-2557-5 -
Digestion 2024Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by chronic abdominal symptoms, but its pathogenesis is not fully understood. (Review)
Review
BACKGROUND
Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by chronic abdominal symptoms, but its pathogenesis is not fully understood.
SUMMARY
We have recently shown in rats that neuropeptides such as orexin, ghrelin, and oxytocin act in the brain to improve the intestinal barrier dysfunction, which is a major pathophysiology of IBS. We have additionally shown that the neuropeptides injected intracisternally induced a visceral antinociceptive action against colonic distension. Since it has been known that intestinal barrier dysfunction causes visceral hypersensitivity, the other main pathophysiology of IBS, the neuropeptides act centrally to reduce leaky gut, followed by improvement of visceral sensation, leading to therapeutic action on IBS. It has been recently reported that there is a bidirectional relationship between neuroinflammation in the brain and the pathophysiology of IBS. For example, activation of microglia in the brain causes visceral hypersensitivity. Accumulating evidence has suggested that orexin, ghrelin, or oxytocin could improve neuroinflammation in the CNS. All these results suggest that neuropeptides such as orexin, ghrelin, and oxytocin act in the brain to improve intestinal barrier function and visceral sensation and also induce a protective action against neuroinflammation in the brain.
KEY MESSAGES
We therefore speculated that orexin, ghrelin, or oxytocin in the brain possess dual actions, improvement of visceral sensation/leaky gut in the gut, and reduction of neuroinflammation in the brain, thereby inducing a therapeutic effect on IBS in a convergent manner.
Topics: Rats; Animals; Irritable Bowel Syndrome; Orexins; Ghrelin; Oxytocin; Neuroinflammatory Diseases; Neuropeptides; Brain
PubMed: 37673052
DOI: 10.1159/000533275 -
Molecular Neurobiology Nov 2022Neuroinflammation in the cardiovascular center plays a critical role in the progression of hypertensive heart disease. And microglial autophagy is involved in the...
Neuroinflammation in the cardiovascular center plays a critical role in the progression of hypertensive heart disease. And microglial autophagy is involved in the regulation of neuroinflammation. Cyclic GMP-AMP synthase (cGAS), a cytosolic DNA sensor, senses mitochondrial DNA (mtDNA) and regulates autophagy. The detailed mechanisms of central cGAS affects neuroinflammatory response in hypertensive heart disease via regulating autophagy remain unknown. Angiotensin II (Ang II, 1.5 mg·kg·12 h, 2 weeks) was intraperitoneally injected to induce hypertension in mice. The cGAS-STING pathway was activated in the paraventricular nucleus (PVN) of Ang II-induced hypertensive mice. The contractile dysfunction of heart was alleviated in Ang II-induced hypertensive cGAS mice. To observe the central effects of cGAS on regulating hypertensive heart disease, the RU.521 (a cGAS inhibitor) was intracisternally infused in hypertensive mice. Intracisternal infusion of the RU.521-alleviated myocardial interstitial fibrosis, cardiomyocyte hypertrophy, and the contractile dysfunction in Ang II-induced hypertensive mice. Intracisternal infusion of RU.521 attenuated the microglial activation, neuroinflammation, sympathetic/parasympathetic activity ratio, and lowered blood pressure. The autophagic flux in the PVN cells was blocked, while intracisternal infusion of RU.521 alleviated this effect in the Ang II-induced hypertensive mice. In vitro, it was found that cGAS-STING activation-induced autophagic flux blockage, while when the impaired autophagic flux was facilitated by rapamycin, an autophagy inducer, the microglial M1 polarization was decreased correspondingly. In conclusion, cGAS induces the inflammatory phenotype of microglia via impairing autophagic flux, thereby participating in neuroinflammation, which leads to sympathetic overactivation in hypertension and further caused hypertensive myocardial injury.
Topics: Angiotensin II; Animals; Autophagy; DNA, Mitochondrial; Heart Diseases; Heart Injuries; Hypertension; Mice; Microglia; Nucleotidyltransferases; Paraventricular Hypothalamic Nucleus; Sirolimus
PubMed: 36070120
DOI: 10.1007/s12035-022-02994-1 -
Viruses Jul 2020Endogenous retroviruses (ERVs) in mammals are closely related to infectious retroviruses and utilize host tRNAs as a primer for reverse transcription and replication, a... (Review)
Review
Endogenous retroviruses (ERVs) in mammals are closely related to infectious retroviruses and utilize host tRNAs as a primer for reverse transcription and replication, a hallmark of long terminal repeat (LTR) retroelements. Their dependency on tRNA makes these elements vulnerable to targeting by small RNAs derived from the 3'-end of mature tRNAs (3'-tRFs), which are highly expressed during epigenetic reprogramming and potentially protect many tissues in eukaryotes. Here, we review some key functions of ERV reprogramming during mouse and human development and discuss how small RNA-mediated silencing maintains genome stability when ERVs are temporarily released from heterochromatin repression. In particular, we take a closer look at the tRNA primer binding sites (PBS) of two highly active ERV families in mice and their sequence variation that is shaped by the conflict of successful tRNA priming for replication versus evasion of silencing by 3'-tRFs.
Topics: Animals; Binding Sites; Endogenous Retroviruses; Gene Silencing; HIV; Host Microbial Interactions; Humans; Mice; RNA, Transfer; Retroelements; Retroviridae Infections; Terminal Repeat Sequences
PubMed: 32718022
DOI: 10.3390/v12080792 -
Neurobiology of Disease Nov 2023The ocular glymphatic system supports bidirectional fluid transport along the optic nerve, thereby removes metabolic wastes including amyloid-β. To better understand...
The ocular glymphatic system supports bidirectional fluid transport along the optic nerve, thereby removes metabolic wastes including amyloid-β. To better understand this biological process, we examined the distributions of intravitreally and intracisternally infused tracers in full-length optic nerves from different age groups of mice. Aging was linked to globally impaired ocular glymphatic fluid transport, similar to what has seen previously in the brain. Aging also reduced the pupillary responsiveness to light stimulation and abolished light-induced facilitation in anterograde ocular glymphatic flow. In contrast to normal aging, in the DBA/2 J model of glaucoma, we found a pathological increase of glymphatic fluid transport to the anterior optic nerve that was associated with dilation of the perivascular spaces. Thus, aging and glaucoma have fundamentally different effects on ocular glymphatic fluid transport. Manipulation of glymphatic fluid transport might therefore present a new target for the treatment of glaucoma.
Topics: Animals; Mice; Mice, Inbred DBA; Glymphatic System; Glaucoma; Face; Aging
PubMed: 37832797
DOI: 10.1016/j.nbd.2023.106322 -
Journal of Neuroinflammation May 2023Depression and dysosmia have been regarded as primary neurological symptoms in COVID-19 patients, the mechanism of which remains unclear. Current studies have...
BACKGROUND
Depression and dysosmia have been regarded as primary neurological symptoms in COVID-19 patients, the mechanism of which remains unclear. Current studies have demonstrated that the SARS-CoV-2 envelope (E) protein is a pro-inflammatory factor sensed by Toll-like receptor 2 (TLR2), suggesting the pathological feature of E protein is independent of viral infection. In this study, we aim to ascertain the role of E protein in depression, dysosmia and associated neuroinflammation in the central nervous system (CNS).
METHODS
Depression-like behaviors and olfactory function were observed in both female and male mice receiving intracisternal injection of E protein. Immunohistochemistry was applied in conjunction with RT-PCR to evaluate glial activation, blood-brain barrier status and mediators synthesis in the cortex, hippocampus and olfactory bulb. TLR2 was pharmacologically blocked to determine its role in E protein-related depression-like behaviors and dysosmia in mice.
RESULTS
Intracisternal injection of E protein evoked depression-like behaviors and dysosmia in both female and male mice. Immunohistochemistry suggested that the E protein upregulated IBA1 and GFAP in the cortex, hippocampus and olfactory bulb, while ZO-1 was downregulated. Moreover, IL-1β, TNF-α, IL-6, CCL2, MMP2 and CSF1 were upregulated in both cortex and hippocampus, whereas IL-1β, IL-6 and CCL2 were upregulated in the olfactory bulb. Furtherly, inhibiting microglia, rather than astrocytes, alleviated depression-like behaviors and dysosmia induced by E protein. Finally, RT-PCR and immunohistochemistry suggested that TLR2 was upregulated in the cortex, hippocampus and olfactory bulb, the blocking of which mitigated depression-like behaviors and dysosmia induced by E protein.
CONCLUSIONS
Our study demonstrates that envelope protein could directly induce depression-like behaviors, dysosmia, and obvious neuroinflammation in CNS. TLR2 mediated depression-like behaviors and dysosmia induced by envelope protein, which could serve as a promising therapeutic target for neurological manifestation in COVID-19 patients.
Topics: Female; Male; Animals; Mice; COVID-19; Depression; Interleukin-6; Neuroinflammatory Diseases; SARS-CoV-2; Toll-Like Receptor 2; Olfaction Disorders
PubMed: 37158916
DOI: 10.1186/s12974-023-02786-x -
Journal of Developmental Origins of... Apr 2019Developmental exposure to phthalates has been implicated as a risk for obesity; however, epidemiological studies have yielded conflicting results and mechanisms are...
Perinatal exposures to phthalates and phthalate mixtures result in sex-specific effects on body weight, organ weights and intracisternal A-particle (IAP) DNA methylation in weanling mice.
Developmental exposure to phthalates has been implicated as a risk for obesity; however, epidemiological studies have yielded conflicting results and mechanisms are poorly understood. An additional layer of complexity in epidemiological studies is that humans are exposed to mixtures of many different phthalates. Here, we utilize an established mouse model of perinatal exposure to investigate the effects of three phthalates, diethylhexyl phthalate (DEHP), diisononyl phthalate (DINP) and dibutyl phthalate (DBP), on body weight and organ weights in weanling mice. In addition to individual phthalate exposures, we employed two mixture exposures: DEHP+DINP and DEHP+DINP+DBP. Phthalates were administered through phytoestrogen-free chow at the following exposure levels: 25 mg DEHP/kg chow, 25 mg DBP/kg chow and 75 mg DINP/kg chow. The viable yellow agouti (A vy ) mouse strain, along with measurement of tail DNA methylation, was used as a biosensor to examine effects of phthalates and phthalate mixtures on the DNA methylome. We found that female and male mice perinatally exposed to DINP alone had increased body weights at postnatal day 21 (PND21), and that exposure to mixtures did not exaggerate these effects. Females exposed to DINP and DEHP+DINP had increased relative liver weights at PND21, and females exposed to a mixture of DEHP+DINP+DBP had increased relative gonadal fat weight. Phthalate-exposed A vy /a offspring exhibited altered coat color distributions and altered DNA methylation at intracisternal A-particles (IAPs), repetitive elements in the mouse genome. These findings provide evidence that developmental exposures to phthalates influence body weight and organ weight changes in early life, and are associated with altered DNA methylation at IAPs.
Topics: Animals; Body Weight; DNA Methylation; Epigenesis, Genetic; Female; Gene Expression Regulation, Developmental; Genes, Intracisternal A-Particle; Male; Mice; Models, Animal; Organ Size; Phthalic Acids; Pregnancy; Sex Factors; Weaning
PubMed: 29991372
DOI: 10.1017/S2040174418000430