scholarly journals Systemic Loss of C-terminal Src Kinase Expression Elicits Spontaneous Suppurative Inflammation in Conditional Knockout Mice

2018 ◽  
Vol 55 (2) ◽  
pp. 331-340 ◽  
Author(s):  
Lisa D. Berman-Booty ◽  
Rukiye Eraslan ◽  
Umesh Hanumegowda ◽  
Glenn H. Cantor ◽  
Denise I. Bounous ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Tyrosine Kinases ◽  
Src Kinase ◽  
Inflammatory Cells ◽  
Conditional Knockout ◽  
Tamoxifen Treatment ◽  
Adult Mice ◽  
Proinflammatory Activity ◽  
Gene Excision ◽  
Kinase Expression

C-terminal Src kinase (Csk) is one of the critical negative regulators of the Src family of kinases. The Src family of kinases are nonreceptor tyrosine kinases that regulate inflammation, cell proliferation, motility, and adhesion. To investigate potential histologic lesions associated with systemic loss of Csk gene activity in adult mice, conditional Csk-knockout mice were examined. Cre-mediated systemic excision of Csk induced by tamoxifen treatment resulted in multiorgan inflammation. Specifically, induction of Csk gene excision with three days of tamoxifen treatment resulted in greater than 90% gene excision. Strikingly, these mice developed enteritis that ranged from minimal and suppurative to severe, fibrinonecrosuppurative and hemorrhagic. Other inflammatory lesions included suppurative pneumonia, gastritis, and myocarditis, and increased numbers of inflammatory cells within the hepatic parenchyma. When tamoxifen treatment was reduced from three days to one day in an effort to lower the level of Csk gene excision and limit lesion development, the mice developed severe suppurative to pyogranulomatous pneumonia and minimal to mild suppurative enteritis. Lesions observed secondary to Csk gene excision suggest important roles for Csk in downregulating the proinflammatory activity of the Src family of kinases and limiting neutrophil-mediated inflammation.

scholarly journals Conditional Deletion of FOXL2 and SMAD4 in Gonadotropes of Adult Mice Causes Isolated FSH Deficiency

Endocrinology ◽  
2018 ◽  
Vol 159 (7) ◽  
pp. 2641-2655 ◽  
Author(s):  
Yining Li ◽  
Gauthier Schang ◽  
Ying Wang ◽  
Xiang Zhou ◽  
Adrien Levasseur ◽  
...  
Keyword(s):  
Ovarian Follicle ◽  
Conditional Knockout ◽  
Tamoxifen Treatment ◽  
Female Sterility ◽  
Follicle Development ◽  
Female Reproduction ◽  
Ovarian Follicle Development ◽  
Adult Mice ◽  
Conditional Deletion ◽  
Driver Line

Abstract The glycoprotein FSH, a product of pituitary gonadotrope cells, regulates ovarian follicle development in females and spermatogenesis in males. FSH is a heterodimer of the common α gonadotropin subunit and the hormone-specific FSHβ subunit (a product of the Fshb gene). Using a conditional knockout approach (Cre-lox), we previously demonstrated that Fshb expression in mice depends on the transcription factors forkhead box L2 (FOXL2) and SMAD4. Deletion of Foxl2 or Smad4 alone led to FSH deficiency, female subfertility, and oligozoospermia in males. Simultaneous deletion of the two genes yielded a greater suppression of FSH and female sterility. The Cre-driver used previously was first active during embryonic development. Therefore, it is unclear whether FOXL2 and SMAD4 play important roles in the development or adult function of gonadotropes, or both. To address this question, we developed a tamoxifen-inducible Cre-driver line, which enabled Foxl2 and Smad4 gene deletions in gonadotropes of adult mice. After tamoxifen treatment, females with previously demonstrated fertility exhibited profound reductions in FSH levels, arrested ovarian follicle development, and sterility. FSH levels were comparably reduced in males 1 or 2 months after treatment; however, spermatogenesis was unaffected. These data indicate that (1) FOXL2 and SMAD4 are necessary to maintain FSH synthesis in gonadotrope cells of adult mice, (2) FSH is essential for female reproduction but appears to be unnecessary for the maintenance of spermatogenesis in adult male mice, and (3) the inducible Cre-driver line developed here provides a powerful tool to interrogate gene function in gonadotrope cells of adult mice.

scholarly journals Dicer Deletion in Astrocytes Inhibits Oligodendroglial Differentiation and Myelination

2021 ◽  
Author(s):  
Kun Liu ◽  
Bin Yu ◽  
Jing-Fei Chen ◽  
Rui-Xue Li ◽  
Lin Chen ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
Spatial Memory ◽  
Knockout Mice ◽  
Motor Coordination ◽  
Conditional Knockout ◽  
Tamoxifen Treatment ◽  
Mouse Line ◽  
Reporter Mouse ◽  
Underlying Mechanisms ◽  
Old Mice

AbstractIncreasing evidence has shown that astrocytes are implicated in regulating oligodendrocyte myelination, but the underlying mechanisms remain largely unknown. To understand whether microRNAs in astrocytes function in regulating oligodendroglial differentiation and myelination in the developing and adult CNS, we generated inducible astrocyte-specific Dicer conditional knockout mice (hGFAP-CreERT; Dicer fl/fl). By using a reporter mouse line (mT/mG), we confirmed that hGFAP-CreERT drives an efficient and astrocyte-specific recombination in the developing CNS, upon tamoxifen treatment from postnatal day 3 (P3) to P7. The Dicer deletion in astrocytes resulted in inhibited oligodendroglial differentiation and myelination in the developing CNS of Dicer cKO mice at P10 and P14, and did not alter the densities of neurons or axons, indicating that Dicer in astrocytes is required for oligodendrocyte myelination. Consequently, the Dicer deletion in astrocytes at P3 resulted in impaired spatial memory and motor coordination at the age of 9 weeks. To understand whether Dicer in astrocytes is also required for remyelination, we induced Dicer deletion in 3-month-old mice and then injected lysolecithin into the corpus callosum to induce demyelination. The Dicer deletion in astrocytes blocked remyelination in the corpus callosum 14 days after induced demyelination. Together, our results indicate that Dicer in astrocytes is required for oligodendroglia myelination in both the developing and adult CNS.

scholarly journals Inducible Neuronal Inactivation of Sim1 in Adult Mice Causes Hyperphagic Obesity

Endocrinology ◽  
2014 ◽  
Vol 155 (7) ◽  
pp. 2436-2444 ◽  
Author(s):  
Kristen P. Tolson ◽  
Terry Gemelli ◽  
Donna Meyer ◽  
Umar Yazdani ◽  
Julia Kozlitina ◽  
...  
Keyword(s):  
Energy Balance ◽  
Knockout Mice ◽  
Conditional Knockout ◽  
Normal Numbers ◽  
Adult Mice ◽  
Melanocortin 4 Receptor ◽  
Regulate Body Weight ◽  
Hypothalamic Nuclei ◽  
Physiologic Function ◽  
Food And Water Intake

Germline haploinsufficiency of human or mouse Sim1 is associated with hyperphagic obesity. Sim1 encodes a transcription factor required for proper formation of the paraventricular (PVN), supraoptic, and anterior periventricular hypothalamic nuclei. Sim1 expression persists in these neurons in adult mice, raising the question of whether it plays a physiologic role in regulation of energy balance. We previously showed that Sim1 heterozygous mice had normal numbers of PVN neurons that were hyporesponsive to melanocortin 4 receptor agonism and showed reduced oxytocin expression. Furthermore, conditional postnatal neuronal inactivation of Sim1 also caused hyperphagic obesity and decreased hypothalamic oxytocin expression. PVN projections to the hindbrain, where oxytocin is thought to act to modulate satiety, were anatomically intact in both Sim1 heterozygous and conditional knockout mice. These experiments provided evidence that Sim1 functions in energy balance apart from its role in hypothalamic development but did not rule out effects of Sim1 deficiency on postnatal hypothalamic maturation. To address this possibility, we used a tamoxifen-inducible, neural-specific Cre transgene to conditionally inactivate Sim1 in adult mice with mature hypothalamic circuitry. Induced Sim1 inactivation caused increased food and water intake and decreased expression of PVN neuropeptides, especially oxytocin and vasopressin, with no change in energy expenditure. Sim1 expression was not required for survival of PVN neurons. The results corroborate previous evidence that Sim1 acts physiologically as well as developmentally to regulate body weight. Inducible knockout mice provide a system for studying Sim1’s physiologic function in energy balance and identifying its relevant transcriptional targets in the hypothalamus.

scholarly journals Postnatal inactivation of Shank3 expression is insufficient to produce behavioral phenotypes associated with germline deficiency

2020 ◽  
Author(s):  
Samuel William Hulbert ◽  
Haidun Yan ◽  
Xiaoming Wang ◽  
Alexandra L. Bey ◽  
Mary S. Lin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Knockout Mice ◽  
Autism Spectrum ◽  
Conditional Knockout ◽  
Mouse Development ◽  
Early Postnatal Development ◽  
Routes Of Administration ◽  
Negative Results ◽  
Conditional Gene Expression ◽  
Adult Mice

Abstract Background: The developmental origins of Autism Spectrum Disorder (ASD) remain largely unknown. To begin to answer this question, a few studies have implemented conditional gene expression technology to induce or rescue ASD-causing mutations at different times during mouse development. Methods: In the current study, we crossed a ubiquitously-expressed inducible Cre line with mice containing loxP sites surrounding Shank3 exons 4-22 (Shank3 e4-22flox). We then delivered tamoxifen to determine the effects of disrupting Shank3 expression during two different time periods in development. Results: We found that reducing Shank3 expression in fully developed mice had minimal effects on behaviors that are characteristic of the conventional knockout mice. Similarly, disrupting Shank3 expression during an earlier time period (postnatal day 10-21) did not induce behaviors associated with germline deficiency. However, we observed differences in electrophysiological phenotypes for the two groups of conditional knockout mice. Conclusions: Because inducing mutations in adult mice or during early postnatal development is insufficient to cause ASD-like behaviors, Shank3 may play a role even earlier in development, but limited efficiency of the disruption could have contributed to our negative results. We also report considerable mortality when delivering tamoxifen across several different routes of administration, bringing further attention to caution the use of this type of conditional gene expression technology in future studies.

Ankyrin-G heterozygous conditional knockout mice display increased sensitivity to social defeat stress

2021 ◽  
Author(s):  
Zachary A. Cordner ◽  
Seva G. Khambadkone ◽  
Shanshan Zhu ◽  
Justin Bai ◽  
Rasadokht Forati ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Social Defeat ◽  
Conditional Knockout ◽  
Social Defeat Stress ◽  
Conditional Knockout Mice ◽  
Ankyrin G ◽  
Increased Sensitivity

scholarly journals Dysregulated Immune Responses by ASK1 Deficiency Alter Epithelial Progenitor Cell Fate and Accelerate Metaplasia Development during H. pylori Infection

2020 ◽  
Vol 8 (12) ◽  
pp. 1995
Author(s):  
Yoku Hayakawa ◽  
Yoshihiro Hirata ◽  
Masahiro Hata ◽  
Mayo Tsuboi ◽  
Yukiko Oya ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Immune Responses ◽  
Cell Fate ◽  
Knockout Mice ◽  
Suppressor Cells ◽  
Inflammatory Cells ◽  
Immune Disorder ◽  
Host Immune Responses ◽  
Epithelial Homeostasis ◽  
H Pylori

The mechanism of H. pylori-induced atrophy and metaplasia has not been fully understood. Here, we demonstrate the novel role of Apoptosis signal-regulating kinase 1 (ASK1) and downstream MAPKs as a regulator of host immune responses and epithelial maintenance against H. pylori infection. ASK1 gene deficiency resulted in enhanced inflammation with numerous inflammatory cells including Gr-1+CD11b+ myeloid-derived suppressor cells (MDSCs) recruited into the infected stomach. Increase of IL-1β release from apoptotic macrophages and enhancement of TH1-polarized immune responses caused STAT1 and NF-κB activation in epithelial cells in ASK1 knockout mice. Dysregulated immune and epithelial activation in ASK1 knockout mice led to dramatic expansion of gastric progenitor cells and massive metaplasia development. Bone marrow transplantation experiments revealed that ASK1 in inflammatory cells is critical for inducing immune disorder and metaplastic changes in epithelium, while ASK1 in epithelial cells regulates cell proliferation in stem/progenitor zone without changes in inflammation and differentiation. These results suggest that H. pylori-induced immune cells may regulate epithelial homeostasis and cell fate as an inflammatory niche via ASK1 signaling.

Reduced hippocampal ten-eleven translocation 3 (Tet3) protein expression in Tet3 conditional knockout mice

2021 ◽  
Vol 26 (5) ◽  
pp. 1425-1425
Author(s):  
Cláudia Antunes ◽  
Jorge D. Da Silva ◽  
Sónia Guerra-Gomes ◽  
Nuno D. Alves ◽  
Fábio Ferreira ◽  
...  
Keyword(s):  
Protein Expression ◽  
Knockout Mice ◽  
Conditional Knockout ◽  
Conditional Knockout Mice
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