Reminder: Campus Stem Cell Seminar Series - Tomorrow, Tuesday Sept. 24th
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JORDANA LENON
Sep 23, 2019, 11:39:25 AM9/23/19
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Hello all,
As a reminder, the next Stem Cell Seminar series will be held tomorrow, Tuesday September 24th – details below.
Time: 12:00 pm – NOON
Location: Wisconsin Institutes for Discovery (WID) – DeLuca Forum (300 S. Orchard St., Rm. 1256)
Speaker: Charu Mehta, SCRMC Trainee, Cell Regenerative Biology (Bresnick Lab)
Topic: RNA-Regulatory Exosome Complex Confers Hematopoietic Progenitor Survival
Abstract: The 11-subunit exosome complex (EC) controls the degradation, processing and synthesis of non-coding and coding RNAs. Although EC actions on RNAs can be highly selective, it controls fundamental biological processes including the DNA damage response, maintenance of genome integrity, stem cell differentiation and erythroid maturation. The EC catalytic subunits Exosc10 and Dis3 mediate the destruction of RNAs in the nucleus. DIS3 is mutated frequently in human multiple myeloma), although the dysregulated RNA targets are not established. McIver et al. demonstrated that EC is an important determinant of erythroid progenitors (BFU-E) and c-Kit signaling. While structural requirements for EC formation and activity are defined, how EC controls cellular processes such as proliferation, survival and differentiation is unclear. During erythropoiesis, the master regulator of erythrocyte development GATA1 represses genes encoding EC subunits. We conducted a multiomic analysis of GATA1-regulated transcripts and proteins in a genetic complementation system, which revealed a disproportionately greater loss of EC catalytic subunits Exosc10 and Dis3 (~5 fold), in comparison with other EC subunits, during erythroid maturation.
As it is unclear if one or both catalytic subunits are required to generate erythroid precursor, BFU-E, and EC catalytic subunit functions have not been analyzed in other progenitor contexts, we tested whether the catalytic subunits function similarly or differentially. We conducted loss-of-function analyses using shRNAs to downregulate Dis3 or Exosc10 in primary mouse fetal liver cells. Loss of Dis3 mRNA did not impact Exosc10 expression and vice versa. Two shRNAs against Dis3 almost entirely ablated erythroid and myeloid colony-forming capacity, whereas two shRNAs against Exosc10 decreased erythroid and myeloid colonies by 65 and 55% respectively. Thus, both catalytic subunits are important determinants of myeloid and erythroid progenitors, and Dis3 perturbations are more detrimental. We compared the importance of Dis3 and Exosc10 for erythroid precursor survival, proliferation and differentiation. Analyses of apoptotic populations revealed that Dis3 downregulation increased the late apoptosis in erythroid precursors. By contrast, Exosc10 downregulation increased early, but not late, apoptosis in precursors. Downregulating Dis3 or Exosc10 reduced surface c-Kit expression in precursors. As ortho- and polychromatic erythroblasts were insensitive to the catalytic subunit alterations, Dis3 and Exosc10 pro-survival functions are cell-type specific. We hypothesized that Dis3 protects precursor cells against apoptosis prior to GATA1 induction of the survival factor Bclxl and may render cells hypersensitive to pro-apoptotic stimuli. We tested this using the apoptosis-inducing kinase inhibitor staurosporine and also growth factor (Epo and SCF) deprivation. The staurosporine EC50 for inducing apoptosis decreased significantly when Dis3 was downregulated. In addition, lowering Epo induced apoptosis in a dose-dependent manner. The loss-of-function system and a genetic rescue assay are being used to elucidate the Dis3-dependent survival mechanism and the impact of human blood disease mutations on this mechanism. Considering the pathogenic consequences of defective erythroid precursor survival, we are evaluating Dis3 function in ineffective erythropoiesis and devising strategies to leverage this mechanism to confer survival to compromised precursor cells.
Reminder: If you are taking this Seminar Series for credit, please check in with Hollie Thompson at the back of the room.
Next Seminar: On Tuesday, October 1st, Farsh Guilak, Co-director, Center of Regenerative Medicine, Washington University, St. Louis, will be speaking on “Engineering STEM Cells with Synthetic Gene Circuits as Novel Therapeutic Delivery Systems.” This talk will be in the Wisconsin Institutes of Discovery (WID), H.F. Deluca Forum in the Town Center on the first floor (map), and will include sandwiches.
A list of the talks for the semester is found at:
https://stemcells.wisc.edu/campus-lab-meeting-schedule/
Thank you,
Hollie Thompson (she, her, hers)
-
Administrator
Stem Cell and Regenerative Medicine Center
1111 Highland Avenue, STE 8457
p. 608-263-2982
e. hjth...@medicine.wisc.edu
As a reminder, the next Stem Cell Seminar series will be held tomorrow, Tuesday September 24th – details below.
Time: 12:00 pm – NOON
Location: Wisconsin Institutes for Discovery (WID) – DeLuca Forum (300 S. Orchard St., Rm. 1256)
Speaker: Charu Mehta, SCRMC Trainee, Cell Regenerative Biology (Bresnick Lab)
Topic: RNA-Regulatory Exosome Complex Confers Hematopoietic Progenitor Survival
Abstract: The 11-subunit exosome complex (EC) controls the degradation, processing and synthesis of non-coding and coding RNAs. Although EC actions on RNAs can be highly selective, it controls fundamental biological processes including the DNA damage response, maintenance of genome integrity, stem cell differentiation and erythroid maturation. The EC catalytic subunits Exosc10 and Dis3 mediate the destruction of RNAs in the nucleus. DIS3 is mutated frequently in human multiple myeloma), although the dysregulated RNA targets are not established. McIver et al. demonstrated that EC is an important determinant of erythroid progenitors (BFU-E) and c-Kit signaling. While structural requirements for EC formation and activity are defined, how EC controls cellular processes such as proliferation, survival and differentiation is unclear. During erythropoiesis, the master regulator of erythrocyte development GATA1 represses genes encoding EC subunits. We conducted a multiomic analysis of GATA1-regulated transcripts and proteins in a genetic complementation system, which revealed a disproportionately greater loss of EC catalytic subunits Exosc10 and Dis3 (~5 fold), in comparison with other EC subunits, during erythroid maturation.
As it is unclear if one or both catalytic subunits are required to generate erythroid precursor, BFU-E, and EC catalytic subunit functions have not been analyzed in other progenitor contexts, we tested whether the catalytic subunits function similarly or differentially. We conducted loss-of-function analyses using shRNAs to downregulate Dis3 or Exosc10 in primary mouse fetal liver cells. Loss of Dis3 mRNA did not impact Exosc10 expression and vice versa. Two shRNAs against Dis3 almost entirely ablated erythroid and myeloid colony-forming capacity, whereas two shRNAs against Exosc10 decreased erythroid and myeloid colonies by 65 and 55% respectively. Thus, both catalytic subunits are important determinants of myeloid and erythroid progenitors, and Dis3 perturbations are more detrimental. We compared the importance of Dis3 and Exosc10 for erythroid precursor survival, proliferation and differentiation. Analyses of apoptotic populations revealed that Dis3 downregulation increased the late apoptosis in erythroid precursors. By contrast, Exosc10 downregulation increased early, but not late, apoptosis in precursors. Downregulating Dis3 or Exosc10 reduced surface c-Kit expression in precursors. As ortho- and polychromatic erythroblasts were insensitive to the catalytic subunit alterations, Dis3 and Exosc10 pro-survival functions are cell-type specific. We hypothesized that Dis3 protects precursor cells against apoptosis prior to GATA1 induction of the survival factor Bclxl and may render cells hypersensitive to pro-apoptotic stimuli. We tested this using the apoptosis-inducing kinase inhibitor staurosporine and also growth factor (Epo and SCF) deprivation. The staurosporine EC50 for inducing apoptosis decreased significantly when Dis3 was downregulated. In addition, lowering Epo induced apoptosis in a dose-dependent manner. The loss-of-function system and a genetic rescue assay are being used to elucidate the Dis3-dependent survival mechanism and the impact of human blood disease mutations on this mechanism. Considering the pathogenic consequences of defective erythroid precursor survival, we are evaluating Dis3 function in ineffective erythropoiesis and devising strategies to leverage this mechanism to confer survival to compromised precursor cells.
Reminder: If you are taking this Seminar Series for credit, please check in with Hollie Thompson at the back of the room.
Next Seminar: On Tuesday, October 1st, Farsh Guilak, Co-director, Center of Regenerative Medicine, Washington University, St. Louis, will be speaking on “Engineering STEM Cells with Synthetic Gene Circuits as Novel Therapeutic Delivery Systems.” This talk will be in the Wisconsin Institutes of Discovery (WID), H.F. Deluca Forum in the Town Center on the first floor (map), and will include sandwiches.
A list of the talks for the semester is found at:
https://stemcells.wisc.edu/campus-lab-meeting-schedule/
Thank you,
Hollie Thompson (she, her, hers)
-
Administrator
Stem Cell and Regenerative Medicine Center
1111 Highland Avenue, STE 8457
p. 608-263-2982
e. hjth...@medicine.wisc.edu
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