Lycium ruthenicum Murr. treatment attenuates APP_(SWE)/PS1ΔE9 mouse model-like mitochondrial dysfunction in Slc25a46 knockout mouse model

Mitochondrial dysfunction is proposed to be substantially associated with ageing and ageing-related diseases like Alzheimer's disease(AD). However, it is unclear whether different mouse models with mitochondrialrelated diseases have similar changes in mitochondrial morphology of the same tissues. Moreover, whether similarities in mitochondrial morphology can be a suitable marker for screening and/or discovering mitochondrial-protective substances remains unknown. Mitochondria morphology in different tissues of a novel mitochondrial outer membrane protein Slc25a46 knockout mouse and a traditional APP_(SWE)/PS1ΔE9 transgenic mouse were examined using transmission electron microscope(TEM). Both young Slc25a46 knockout mice and aged APP_(SWE)/PS1ΔE9 mice models showed similar mitochondrial damage in cerebellum tissues. The results indicated that different mitochondrial-related diseases shared similar alteration and defects in mitochondrial morphology. Furthermore, Lycium ruthenicum Murr. extract, a bioactive food substance with cognition-improving property, could effectively improve muscle strength and increase body weight in the Slc25a46 knockout mice. These findings suggest that mitochondrial morphology defects in mice models, particularly in the mitochondrial compartment, represent a unified and effective marker for screening and validating natural product-derived functional substances with mitochondrial protective properties. It also holds potential application in mitochondrial-impaired senile neurodegenerative diseases, especially in AD.

Human androgen deficiency： insights gained from androgen receptor knockout mouse models

The mechanism of androgen action is complex. Recently, significant advances have been made into our understanding of how androgens act via the androgen receptor （AR） through the use of genetically modified mouse models. A number of global and tissue-specific AR knockout （ARKO） models have been generated using the Cre-loxP system which allows tissue- and/or cell-specific deletion. These ARKO models have examined a number of sites of androgen action including the cardiovascular system, the immune and hemopoetic system, bone, muscle, adipose tissue, the prostate and the brain. This review focuses on the insights that have been gained into human androgen deficiency through the use of ARKO mouse models at each of these sites of action, and highlights the strengths and limitations of these Cre-loxP mouse models that should be considered to ensure accurate interpretation of the phenotype.

Instability of microsatellites linked to targeted genes inCRISPR/Cas9-edited and traditional gene knockout mouse strains

The classic method for gene knockout (KO) is based on homologous recombination (HR) and embryonic stem cell technique (Gerlai,1996).Actually,the procedure of homologous replacement is complicated and time consuming,although it has been popular during the past decades.Recent years,genome editing which can cause DNA sequence-specific mutations in the genomes of cellular

High-throughput screening of mouse gene knockouts identifies established and novel skeletal phenotypes

Screening gene function in vivo is a powerful approach to discover novel drug targets. We present high-throughput screening （HTS） data for 3 762 distinct global gene knockout （KO） mouse lines with viable adult homozygous mice generated using either gene-trap or homologous recombination technologies. Bone mass was determined from DEXA scans of male and female mice at 14 weeks of age and by microCT analyses of bones from male mice at 16 weeks of age. Wild-type （WT） cagemates/littermates were examined for each gene KO. Lethality was observed in an additional 850 KO lines. Since primary HTS are susceptible to false positive findings, additional cohorts of mice from KO lines with intriguing HTS bone data were examined. Aging, ovariectomy, histomorphometry and bone strength studies were performed and possible non-skeletal phenotypes were explored. Together, these screens identified multiple genes affecting bone mass： 23 previously reported genes （Calcr, Cebpb, Crtap, Dcstamp, Dkkl, Duoxa2, Enppl, Fgf23, Kissl/Kisslr, Kl （Klotho）, Lrp5, Mstn, Neol, Npr2, Ostml, Postn, Sfrp4, S1c30a5, Sic39a13, Sost, Sumf1, Src, Wnt10b）, five novel genes extensively characterized （Cldn18, Fam20c, Lrrkl, Sgpll, Wnt16）, five novel genes with preliminary characterization （Agpat2, RassfS, Slc10a7, Stc26a7, Slc30a10） and three novel undisclosed genes coding for potential osteoporosis drug targets.

Designing and generating a mouse model:frequently asked questions

Genetically engineered mouse(GEM)models are commonly used in biomedical research.Generating GEMs involve complex set of experimental procedures requiring sophisticated equipment and highly skilled technical staff.Because of these reasons,most research institutes set up centralized core facilities where custom GEMs are created for research groups.Researchers,on the other hand,when they begin thinking about generating GEMs for their research,several questions arise in their minds.For example,what type of model(s)would be best useful for my research,how do I design them,what are the latest technologies and tools available for developing my model(s),and finally how to breed GEMs in my research.As there are several considerations and options in mouse designs,and as it is an expensive and time-consuming endeavor,careful planning upfront can ensure the highest chance of success.In this article,we provide brief answers to several frequently asked questions that arise when researchers begin thinking about generating mouse model(s)for their work.

Deletion of phosphatidylserine flippase β-subunit Tmem30a in satellite cells leads to delayed skeletal muscle regeneration

Phosphatidylserine(PS)is distributed asymmetrically in the plasma membrane of eukaryotic cells.Phosphatidylserine flippase(P4-ATPase)transports PS from the outer leaflet of the lipid bilayer to the inner leaflet of the membrane to maintain PS asymmetry.TheβsubunitTMEM30 Ais indispensable for transport and proper function of P4-ATPase.Previous studies have shown that the ATP11 A and TMEM30 A complex is the molecular switch for myotube formation.However,the role of Tmem30 a in skeletal muscle regeneration remains elusive.In the current study,Tmem30 a was highly expressed in the tibialis anterior(TA)muscles of dystrophin-null(mdx)mice and BaCl2-induced muscle injury model mice.We generated a satellite cell(SC)-specific Tmem30 a conditional knockout(cKO)mouse model to investigate the role of Tmem30 a in skeletal muscle regeneration.The regenerative ability of cKO mice was evaluated by analyzing the number and diameter of regenerated SCs after the TA muscles were injured by BaCl2-injection.Compared to the control mice,the cKO mice showed decreased Pax7+and MYH3+SCs,indicating diminished SC proliferation,and decreased expression of muscular regulatory factors(MYOD and MYOG),suggesting impaired myoblast proliferation in skeletal muscle regeneration.Taken together,these results demonstrate the essential role of Tmem30 a in skeletal muscle regeneration.

Fibrinogen deficiency suppresses the development of early and delayed radiation enteropathy

To determine the mechanistic role of fibrinogen, a key regulator of inflammation and fibrosis, in early and delayed radiation enteropathy. METHODSFibrinogen wild-type (Fib+/+), fibrinogen heterozygous (Fib+/-), and fibrinogen knockout (Fib-/-) mice were exposed to localized intestinal irradiation and assessed for early and delayed structural changes in the intestinal tissue. A 5-cm segment of ileum of mice was exteriorized and exposed to 18.5 Gy of x-irradiation. Intestinal tissue injury was assessed by quantitative histology, morphometry, and immunohistochemistry at 2 wk and 26 wk after radiation. Plasma fibrinogen level was measured by enzyme-linked immunosorbent assay. RESULTSThere was no difference between sham-irradiated Fib+/+ and Fib+/- mice in terms of fibrinogen concentration in plasma and intestinal tissue, intestinal histology, morphometry, intestinal smooth muscle cell proliferation, and neutrophil infiltration. Therefore, Fib+/- mice were used as littermate controls. Unlike sham-irradiated Fib+/+ and Fib+/- mice, no fibrinogen was detected in the plasma and intestinal tissue of sham-irradiated Fib-/- mice. Moreover, fibrinogen level was not elevated after irradiation in the intestinal tissue of Fib-/- mice, while significant increase in intestinal fibrinogen level was noticed in irradiated Fib+/+ and Fib+/- mice. Importantly, irradiated Fib-/- mice exhibited substantially less overall intestinal structural injury (RIS, P = 0.000002), intestinal wall thickness (P = 0.003), intestinal serosal thickness (P = 0.009), collagen deposition (P = 0.01), TGF-β immunoreactivity (P = 0.03), intestinal smooth muscle proliferation (P = 0.046), neutrophil infiltration (P = 0.01), and intestinal mucosal injury (P = 0.0003), compared to irradiated Fib+/+ and Fib+/- mice at both 2 wk and 26 wk. CONCLUSIONThese data demonstrate that fibrinogen deficiency directly attenuates development of early and delayed radiation enteropathy. Fibrinogen could be a novel target in treating intestinal damage.

NADPH oxidase-1 deficiency offers little protection in Salmonella typhimurium-induced typhlitis in mice

AIM To test whether Nox1 plays a role in typhlitis induced by Salmonella enterica serovar Typhimurium(S. Tm) in a mouse model.METHODS Eight-week-old male wild-type(WT) and Nox1 knockout(KO) C57BL6/J(B6) mice were administered metronidazole water for 4 d to make them susceptible to S. Tm infection by the oral route. The mice were given plain water and administered with 4 different doses of S. Tm by oral gavage. The mice were followed for another 4 d. From the time of the metronidazole application, the mice were observed twice daily and weighed daily. The ileum, cecum and colon were removed for sampling at the fourth day post-inoculation. Portions of all three tissues were fixed for histology and placed in RNAlater for m RNA/c DNA preparation and quantitative real-time PCR. The contents of the cecum were recovered for estimation of S. Tm CFU.RESULTS We found Nox1-knockout(Nox1-KO) mice were not more sensitive to S. Tm colonization and infection than WT B6 mice. This conclusion is based on the following observations:(1) S. Tm-infection induced similar weight loss in Nox1-KO mice compared to WT mice;(2) the same S. Tm CFU was recovered from the cecal content of Nox1-KO and WT mice regardless of the inoculation dose, except the lowest inoculation dose(2 × 106 CFU) for which the Nox1-KO had one-log lower CFU than WT mice;(3) there is no difference in cecal pathology between WT and Nox1-KO groups; and(4) there are no S. Tm infection-induced changes in gene expression levels(IL-1b, TNF-α, and Duox2) between WT and Nox1-KO groups. The Alpi gene expression was more suppressed by S. Tm treatment in WT than the Nox1-KO cecum. CONCLUSION Nox1 does not protect mice from S. Tm colonization. Nox1-KO provides a very minor protective effect against S. Tm infection. Using NOX1-specific inhibitors for colitis therapy should not increase risks in bacterial infection.

Deletion of Gpr128 results in weight loss and increased intestinal contraction frequency

AIM: To generate a Gpr128 gene knockout mouse model and to investigate its phenotypes and the biological function of the Gpr128 gene.

Rare loss-of-function variants in FLNB cause non-syndromic orofacial clefts

Orofacial clefts (OFCs) are the most common congenital craniofacial disorders, of which the etiology is closely related to rare coding variants. Filamin B (FLNB) is an actin-binding protein implicated in bone formation. FLNB mutations have been identified in several types of syndromic OFCs and previous studies suggest a role of FLNB in the onset of non-syndromic OFCs (NSOFCs). Here, we report two rare heterozygous variants (p.P441T and p.G565R) in FLNB in two unrelated hereditary families with NSOFCs. Bioinformatics analysis suggests that both variants may disrupt the function of FLNB. In mammalian cells, p.P441T and p.G565R variants are less potent to induce cell stretches than wild type FLNB, suggesting that they are loss-of-function mutations. Immunohistochemistry analysis demonstrates that FLNB is abundantly expressed during palatal development. Importantly, Flnb^(−/−) embryos display cleft palates and previously defined skeletal defects. Taken together, our findings reveal that FLNB is required for development of palates in mice and FLNB is a bona fide causal gene for NSOFCs in humans.

TLR4 inactivation protects from graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Graft-versus-host disease （GVHD） is the most common complication after hematopoietic stem cell transplantation. To clarify the role of Toll-like receptor 4 （TLR4）, which is a major receptor for bacterial lipopolysaccharides （LPS）, in the development of acute GVHD, we used a TLR4-knockout （TLR4-/-） mouse GVHD model and analyzed the underlying immunological mechanisms. When TLR4-/- mice were used as bone marrow and splenocyte cell graft donors or recipients, GVHD symptom occurrence and mortality were delayed compared to wild-type （TLR4＋/＋） mice. In addition, histopathological analyses revealed that in TLR4-/-→BALB/c chimeras, liver and small intestine tissue damage was reduced with minimal lymphocytic infiltration. In contrast to TLR4＋/＋, TLR4-/- mice dendritic cells did not express CD80, CD86, CD40, MHC-II or IL-12 during LPS induction and remained in an immature state. Furthermore, the ability of TLR4-/- mice spleen dendritic cells to promote allogeneic T-cell proliferation and, in particular, T-helper cell 1 （Th 1） development was obviously attenuated compared with TLR4＋/＋ mice dendritic cells, and the levels of interferon-T （IFN-γ） and IL-IO, Th2-cell specific cytokines, were significantly higher in the serum of TLR4-/-→BALB/c than in TLR4＋/＋→BALB/c chimeric mice. Overall, our data revealed that TLR4 may play a role in the pathogenesis of GVHD and that targeted TLR4 gene therapy might provide a new treatment approach to reduce the risk of GVHD.

Deletion of Gab2 in mice protects against hepatic steatosis and steatohepatitis:a novel therapeutic target for fatty liver disease

Fatty liver disease is a serious health problem worldwide and is the most common cause for chronic liver disease and metabolic disorders.The major challenge in the prevention and intervention of this disease is the incomplete understanding of the underlying mechanism and thus lack of potent therapeutic targets due to multifaceted and interdependent disease factors.In this study,we investigated the role of a signaling adaptor protein,GRB2-associated-binding protein 2(Gab2),in fatty liver using an animal disease model.Gab2 expression in hepatocytes responded to various disease factor stimulations,and Gab2 knockout mice exhibited resistance to fat-induced obesity,fat-or alcohol-stimulated hepatic steatosis,as well as methionine and choline deficiency-induced steatohepatitis.Concordantly,the forced expression or knockdown of Gab2 enhanced or diminished oleic acid(OA)-or ethanol-induced lipid production in hepatocytes in vitro,respectively.During lipid accumulation in hepatocytes,both fat and alcohol induced the recruitment of PI3K or Socs3 by Gab2 and the activation of their downstream signaling proteins AKT,ERK,and Stat3.Therefore,Gab2 may be a disease-associated protein that is induced by pathogenic factors to amplify and coordinate multifactor-induced signals to govern disease development in the liver.Our research provides a novel potential target for the prevention and intervention of fatty liver disease.

Bone Morphogenetic Protein (BMP) signaling in development and human diseases

Bone Morphogenetic Proteins(BMPs)are a group of signaling molecules that belongs to the Transforming Growth Factor-b(TGF-b)superfamily of proteins.Initially discovered for their ability to induce bone formation,BMPs are now known to play crucial roles in all organ systems.BMPs are important in embryogenesis and development,and also in maintenance of adult tissue homeostasis.Mouse knockout models of various components of the BMP signaling pathway result in embryonic lethality or marked defects,highlighting the essential functions of BMPs.In this review,we first outline the basic aspects of BMP signaling and then focus on genetically manipulated mouse knockout models that have helped elucidate the role of BMPs in development.A significant portion of this review is devoted to the prominent human pathologies associated with dysregulated BMP signaling.

Spermatogenic Cell-Specific Gene Mutation in Mice via CRISPR-Cas9

Tissue-specific knockout technology enables the analysis of the gene function in specific tissues in adult mammals.However,conventional strategy for producing tissue-specific knockout mice is a time- and labor-consuming process,restricting rapid study of the gene function in vivo.CRISPR-Cas9 system from bacteria is a simple and efficient gene-editing technique,which has enabled rapid generation of gene knockout lines in mouse by direct injection of CRISPR-Cas9 into zygotes.Here,we demonstrate CRISPR-Cas9-mediated spermatogenic cell-specific disruption of Scp3 gene in testes in one step.We first generated transgenic mice by pronuclear injection of a plasmid containing Hspa2 promoter driving Cas9 expression and showed Cas9 specific expression in spermatogenic cells.We then produced transgenic mice carrying Hspa2 promoter driven Cas9 and constitutive expressed sgRNA targeting Scp3 gene.Male founders were infertile due to developmental arrest of spermatogenic cells while female founders could produce progeny normally.Consistently,male progeny from female founders were infertile and females could transmit the transgenes to the next generation.Our study establishes a CRISPR-Cas9-based one-step strategy to analyze the gene function in adult tissues by a temporal-spatial pattern.