L-Calc™ Software

Software for limiting dilution analysis

L-Calc™ Software

Software for limiting dilution analysis

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Software for limiting dilution analysis
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Overview

Limiting Dilution Analysis (LDA) has been applied to the in vitro quantitation of hematopoietic stem cells (HSCs) using assays such as the long term culture-initiating cell (LTC-IC) assay (Conneally et al.) and the cobblestone area forming cell (CAFC) assay (Wang et al.). Limiting dilution protocols have also been adapted to allow the quantitation of human and mouse HSCs with the capacity to produce mature cells of all hematopoietic lineages in vivo, in competitive repopulating unit (CRU) (Ploemacher et al.; Szilvassy et al.) and SCID repopulating cell (SRC) assays (Dick et al.).

L-Calc™ will assist you in analyzing the results of your LDA. For each experiment, values corresponding to dose (i.e. cells per well); total number of positive responses obtained per dose; and total number of replicates tested (i.e. total number of wells used per cell dose) are entered. From these data, the frequency of cells within a given cell population capable of a defined response is determined. L-Calc™ can also be used as a guide to assess differences between paired sets of LDAs. A statistician should be consulted to perform the appropriate comparison.

Free Software Download Available: lcsetup.exe

Suitable for use with Microsoft® Windows.
Please note we no longer provide support or updates for L-Calc software.
Application
Functional Assay
Area of Interest
Stem Cell Biology

Applications

This product is designed for use in the following research area(s) as part of the highlighted workflow stage(s). Explore these workflows to learn more about the other products we offer to support each research area.

Resources and Publications

Publications (18)

p53-TP53-Induced Glycolysis Regulator Mediated Glycolytic Suppression Attenuates DNA Damage and Genomic Instability in Fanconi Anemia Hematopoietic Stem Cells. X. Li et al. Stem cells (Dayton, Ohio) 2019 jul

Abstract

Emerging evidence has shown that resting quiescent hematopoietic stem cells (HSCs) prefer to utilize anaerobic glycolysis rather than mitochondrial respiration for energy production. Compelling evidence has also revealed that altered metabolic energetics in HSCs underlies the onset of certain blood diseases; however, the mechanisms responsible for energetic reprogramming remain elusive. We recently found that Fanconi anemia (FA) HSCs in their resting state are more dependent on mitochondrial respiration for energy metabolism than on glycolysis. In the present study, we investigated the role of deficient glycolysis in FA HSC maintenance. We observed significantly reduced glucose consumption, lactate production, and ATP production in HSCs but not in the less primitive multipotent progenitors or restricted hematopoietic progenitors of Fanca-/- and Fancc-/- mice compared with that of wild-type mice, which was associated with an overactivated p53 and TP53-induced glycolysis regulator, the TIGAR-mediated metabolic axis. We utilized Fanca-/- HSCs deficient for p53 to show that the p53-TIGAR axis suppressed glycolysis in FA HSCs, leading to enhanced pentose phosphate pathway and cellular antioxidant function and, consequently, reduced DNA damage and attenuated HSC exhaustion. Furthermore, by using Fanca-/- HSCs carrying the separation-of-function mutant p53R172P transgene that selectively impairs the p53 function in apoptosis but not cell-cycle control, we demonstrated that the cell-cycle function of p53 was not required for glycolytic suppression in FA HSCs. Finally, ectopic expression of the glycolytic rate-limiting enzyme PFKFB3 specifically antagonized p53-TIGAR-mediated metabolic reprogramming in FA HSCs. Together, our results suggest that p53-TIGAR metabolic axis-mediated glycolytic suppression may play a compensatory role in attenuating DNA damage and proliferative exhaustion in FA HSCs. Stem Cells 2019;37:937-947.
Metformin blunts muscle hypertrophy in response to progressive resistance exercise training in older adults: A randomized, double-blind, placebo-controlled, multicenter trial: The MASTERS trial. R. G. Walton et al. Aging cell 2019 dec

Abstract

Progressive resistance exercise training (PRT) is the most effective known intervention for combating aging skeletal muscle atrophy. However, the hypertrophic response to PRT is variable, and this may be due to muscle inflammation susceptibility. Metformin reduces inflammation, so we hypothesized that metformin would augment the muscle response to PRT in healthy women and men aged 65 and older. In a randomized, double-blind trial, participants received 1,700 mg/day metformin (N = 46) or placebo (N = 48) throughout the study, and all subjects performed 14 weeks of supervised PRT. Although responses to PRT varied, placebo gained more lean body mass (p = .003) and thigh muscle mass (p {\textless} .001) than metformin. CT scan showed that increases in thigh muscle area (p = .005) and density (p = .020) were greater in placebo versus metformin. There was a trend for blunted strength gains in metformin that did not reach statistical significance. Analyses of vastus lateralis muscle biopsies showed that metformin did not affect fiber hypertrophy, or increases in satellite cell or macrophage abundance with PRT. However, placebo had decreased type I fiber percentage while metformin did not (p = .007). Metformin led to an increase in AMPK signaling, and a trend for blunted increases in mTORC1 signaling in response to PRT. These results underscore the benefits of PRT in older adults, but metformin negatively impacts the hypertrophic response to resistance training in healthy older individuals. ClinicalTrials.gov Identifier: NCT02308228.
Crebbp haploinsufficiency in mice alters the bone marrow microenvironment, leading to loss of stem cells and excessive myelopoiesis. Zimmer SN et al. Blood 2011 JUL

Abstract

CREB-binding protein (CREBBP) is important for the cell-autonomous regulation of hematopoiesis, including the stem cell compartment. In the present study, we show that CREBBP plays an equally pivotal role in microenvironment-mediated regulation of hematopoiesis. We found that the BM microenvironment of Crebbp(+/-) mice was unable to properly maintain the immature stem cell and progenitor cell pools. Instead, it stimulates myeloid differentiation, which progresses into a myeloproliferation phenotype. Alterations in the BM microenvironment resulting from haploinsufficiency of Crebbp included a marked decrease in trabecular bone that was predominantly caused by increased osteoclastogenesis. Although CFU-fibroblast (CFU-F) and total osteoblast numbers were decreased, the bone formation rate was similar to that found in wild-type mice. At the molecular level, we found that the known hematopoietic modulators matrix metallopeptidase-9 (MMP9) and kit ligand (KITL) were decreased with heterozygous levels of Crebbp. Lastly, potentially important regulatory proteins, endothelial cell adhesion molecule 1 (ESAM1) and cadherin 5 (CDH5), were increased on Crebbp(+/-) endothelial cells. Our findings reveal that a full dose of Crebbp is essential in the BM microenvironment to maintain proper hematopoiesis and to prevent excessive myeloproliferation.