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Results for “Functional differentiation”

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PubMed2026

Studies on functional differentiation of xpr1a and xpr1b genes in zebrafish.

Xenotropic and polytropic retrovirus receptor 1 (XPR1) is known to be involved in various biological processes, including phosphate homeostasis, cellular signaling, brain and vascular mineralization, whereas its specific contribution to bone development remains incompletely characterized. Due to genome duplication in teleosts, zebrafish Danio rerio possess two paralogous genes of XPR1 namely xpr1a and xpr1b, whose functional divergence remains unclear. The amino acid sequence similarity between zebrafish xpr1a and xpr1b was 83.26%. In situ hybridization demonstrated overlapping localization in the head and spinal cord at 24-48 hpf, while diverged by 72 hpf, with xpr1a becoming restricted to the head while xpr1b persisted in both regions. CRISPR/Cas9 was used to generate xpr1a and xpr1b mutants. The xpr1a mutants are comparatively healthy, viable but with mild growth reduction, whereas the xpr1b mutants display high mortality, reduced body length and severe vertebral deformities. Interestingly, all the double mutants died at the embryonic stage. Moreover, to further investigate the molecular and regulatory mechanisms, we conducted comparative transcriptome analysis on bone and brain tissues from xpr1b+/+ and xpr1b-/- zebrafish. In bone tissue, 6749 DEGs were identified, comprising 3846 upregulated and 2903 downregulated genes. These DEGs were mainly enriched in the MAPK signaling pathway, Wnt signaling pathway, cysteine and methionine metabolism, and ECM-receptor interaction. RT-qPCR validated results showed that seven osteogenesis-related genes (col1a1a, sp7, runx2b, col1a2, col1a1b, alp1 and entpd5), and two phosphate homeostasis related genes (slc20a2 and pdgfba), which are essential for skeletal mineralization and phosphate homeostasis, exhibited significantly downregulated expression in bone tissue of xpr1b mutant zebrafish. These results highlight the pivotal role of xpr1b in regulating skeletal mineralization and phosphate metabolism, thereby elucidating the functional specialization of XPR1 paralogs while providing a theoretical basis for understanding bone developmental mechanism in teleost vertebrates.

Animals↗
PubMed1981

Functional differentiation within the tensor fasciae latae. A telemetered electromyographic analysis of its locomotor roles.

Electromyograms recorded by three or four fine-wire bipolar electrodes inserted along a transverse line across the right tensor fasciae latae of ten normal adults (five men and five women, twenty to thirty-six years old) during a standardized series of exercises and locomotor activities demonstrated different functional roles for the anteromedial and posterolateral fibers of the muscle. Although anatomical dissections in six normal cadavera demonstrated that the force of contraction of the tensor fasciae latae could be transmitted to the knee by the iliotibial tract, the observed activity of this muscle can be explained completely in terms of its action at the hip. The anteromedial fibers have a greater mechanical advantage for hip flexion than do the posterolateral fibers, whereas the posterolateral fibers possess a better mechanical advantage for hip abduction and internal rotation. During walking the anteromedial fibers were electromyographically silent, whereas the posterolateral fibers were active near heel-strike. For all subjects, increased locomotor velocity (during jogging, running, and sprinting) was associated both with increased activity of the anteromedial fibers near toe-off apparently to assist deceleration of extension and acceleration of flexion of the thigh, and with increased activity of the posterolateral fibers at heel-strike.

Adult↗
PubMed1989

Regulation of Sertoli cell differentiated function: testicular transferrin and androgen-binding protein expression.

The regulation of Sertoli cell function was investigated through an examination of the effects of various hormones, regulatory agents, and culture conditions on testicular transferrin and androgen-binding protein (ABP) synthesis and steady state levels of mRNA. FSH stimulated both transferrin and ABP production 2-fold above control levels. Interestingly, FSH had a differential effect on transferrin and ABP mRNA levels, with 1.25- and 2.0-fold respective increases in steady state levels of mRNA. Insulin and retinol stimulated both transferrin and ABP synthesis in a similar manner. Testosterone had no significant effect on either transferrin or ABP mRNA levels or synthesis. Maximum stimulation of both transferrin and ABP production occurred when Sertoli cell cultures were treated with a combination of FSH, insulin, and retinol, which resulted in a greater than 4-fold stimulation of synthesis and 2-fold stimulation of gene expression. Optimal transferrin and ABP secretion occurred between days 4-6 of Sertoli cell culture and subsequently declined. Sertoli cell number decreased with time in culture, such that approximately a 50% loss of cells was observed after 10 days of culture. The responsiveness of Sertoli cells to regulatory agents was altered by cell density, with a maximum responsiveness achieved at a density of 12 micrograms DNA/2 cm2 for both transferrin and ABP. As the cell density deviated from this level the responsiveness of cells to regulatory agents decreased and approached control values. These observations indicate that the culture conditions and the method of data normalization are important parameters in an analysis of the hormonal regulation of Sertoli cell function. FSH actions on Sertoli cells increased both cellular and excreted cAMP levels but had no effect on cGMP levels. (Bu)2 cAMP affected transferrin and ABP mRNA levels and synthesis in a similar manner, with approximately a 3-fold increase in synthesis and a 1.5-fold increase in steady state levels of mRNA. The minimum and maximum effective concentrations of (Bu)2AMP for both proteins were 1 and 10 microM, respectively. Observations imply that regulatory agents that act via a cAMP-mediated signal transduction mechanism, such as FSH, will probably have similar actions on transferrin and ABP production. In addition, data obtained with insulin and retinol indicate that transferrin and ABP production can be similarly regulated with cAMP-independent signal transduction mechanisms. Results indicate that transferrin and ABP mRNA levels and synthesis are regulated in a coordinate manner with the regulatory agents and culture conditions evaluated.(ABSTRACT TRUNCATED AT 400 WORDS)

Androgen-Binding Protein↗
PubMed2002

Expression of hypoxia-inducible factors in the peri-implantation mouse uterus is regulated in a cell-specific and ovarian steroid hormone-dependent manner. Evidence for differential function of HIFs during early pregnancy.

Increased uterine vascular permeability and angiogenesis are hallmarks of implantation and placentation. These events are profoundly influenced by vascular endothelial growth factor (VEGF). We previously showed that VEGF isoforms and VEGF receptors are expressed in the uterus, suggesting the role of VEGF in uterine vascular permeability and angiogenesis required for implantation and decidualization. We have recently shown that estrogen promotes uterine vascular permeability but inhibits angiogenesis, whereas progesterone stimulates angiogenesis with little effect on vascular permeability. However, the mechanism of differential steroid hormonal regulation of uterine angiogenesis remains unresolved. Oxygen homeostasis is essential for cell survival and is primarily mediated by hypoxia-inducible factors (HIFs). These factors are intimately associated with vascular events and induce VEGF expression by binding to the hypoxia response element in the VEGF promoter. HIFalpha isoforms function by forming heterodimers with the aryl hydrocarbon nuclear translocator (ARNT) (HIF-beta) family members. There is very limited information on the relationship among HIFs, ARNTs, and VEGF in the uterus during early pregnancy, although the role of HIFs in regulating VEGF and angiogenesis in cancers is well documented. Using molecular and physiological approaches, we here show that uterine expression of HIFs and ARNTs does not correlate with VEGF expression during the preimplantation period (days 1-4) in mice. In contrast, their expression follows the localization of uterine VEGF expression with increasing angiogenesis during the postimplantation period (days 5-8). This disparate pattern of uterine HIFs, ARNTs, and VEGF expression on days 1-4 of pregnancy suggests HIFs have multiple roles in addition to the regulation of angiogenesis during the peri-implantation period. Using pharmacological, molecular, and genetic approaches, we also observed that although progesterone primarily up-regulates uterine HIF-1alpha expression, estrogen transiently stimulates that of HIF-2alpha.

Animals↗
PubMed2006

Local intrahepatic CD8+ T cell activation by a non-self-antigen results in full functional differentiation.

The response of T cells to liver Ags sometimes results in immune tolerance. This has been proposed to result from local, intrahepatic priming, while the expression of the same Ag in liver-draining lymph nodes is believed to result in effective immunity. We tested this model, using an exogenous model Ag expressed only in hepatocytes, due to infection with an adeno-associated virus vector. T cell activation was exclusively intrahepatic, yet in contrast to the predictions of the current model, this resulted in clonal expansion, IFN-gamma synthesis, and cytotoxic effector function. Local activation of naive CD8(+) T cells can therefore cause full CD8(+) T cell activation, and hepatocellular presentation cannot be used to explain the failure of CTL effector function against some liver pathogens such as hepatitis C.

Adoptive Transfer↗
PubMed1983

The culture of chick embryo chondrocytes and the control of their differentiated functions in vitro. Transformation by rous sarcoma virus induces a switch in the collagen type synthesis and enhances fibronectin expression.

Epithelial-like chondrocytes obtained from chick embryo were transformed with Rous sarcoma virus. Cellular transformation was monitored looking at the morphology change, the cell growth, and the expression of plasminogen activator. Analysis on polyacrylamide gel of intracellular and secreted proteins showed: 1) a disappearance of the specific products of differentiated chondrocytes; 2) a switch in the collagen synthesis from the type II, the chondrocyte-specific type, to the type I, characteristic of fibroblasts and other cells of mesenchymal origin; 3) an enhancement of fibronectin synthesis. Analysis of the proteins from chondrocytes infected with Rous-associated virus 1, a virus unable to induce cell transformation in vitro, indicated that the altered expression of the differentiated proteins in Rous sarcoma virus-infected chondrocytes depended upon the action of src gene product.

Animals↗
PubMed1995

EGF and TGF alpha modulate structural and functional differentiation of the mammary gland from pregnant mice in vitro: possible role of the arachidonic acid pathway.

Epidermal growth factor (EGF) has been suggested to be involved in mammary gland development by mitogenic stimulation of the ductal and alveolar epithelium in virgin mice. The present studies demonstrate that also in late-pregnant mice EGF leads to proliferation of the ductal, ductular, and alveolar epithelium. The mitogenic effect is associated with structural and functional dedifferentiation of alveolar cells as revealed by analysis of morphology, expression of cytosolic and secretory proteins, and fatty acid synthesis. Using a combination of metabolic inhibitors, the dedifferentiating effect of EGF could be blocked while the mitogenic action was not influenced. This finding demonstrates that the signal transduction pathway leading to dedifferentiation and mitosis can be separated, and that the dedifferentiating effect of EGF is independent of its mitogenic properties, but is probably mediated by activation of the arachidonic acid-dependent pathways (cyclo- and lipoxygenase pathways). Release of arachidonic acid from the endogenous phospholipid pool was found to be an early response of the explants to EGF. Accordingly, arachidonic acid itself proved to be capable of inducing epithelial dedifferentiation but failed to stimulate proliferation. TGF alpha showed qualitatively similar effects as EGF but was generally a stronger agonist. It is suggested that EGF and TGF alpha also play a role in mammary gland physiology during pregnancy by final developing and maintenance of the lobulo-alveolar structure in the mammary gland and prevention of premature onset of lactation, and that this is mediated through the PLA2-arachidonic acid signalling cascade.

Animals↗
PubMed1983

Reciprocal modulation of growth and differentiated functions of mature rat hepatocytes in primary culture by cell--cell contact and cell membranes.

In primary monolayer cultures of rat mature hepatocytes, many metabolic functions as well as cell growth are regulated by cell density. There are two types of regulatory response of these functions to change of cell density. Growth-related functions, such as DNA synthesis, induction of glucose-6-phosphate dehydrogenase, 2-aminoisobutyric acid transport, synthesis of cellular protein, and cholesterogenesis, are stimulated by low cell density. In contrast, functions related to hepatocyte-specific characters, such as the inductions of tyrosine aminotransferase, serine dehydratase, and malic enzyme and synthesis of triglycerides, are stimulated by high cell density. The reciprocal responses of these cellular activities to cell density were mimicked by addition of plasma membranes purified from adult rat liver to hepatocytes cultured at low cell density. The modulator activity was heat labile and trypsin sensitive. The activity was also found in plasma membranes from kidney, brain, and erythrocytes, although the specific activities of these preparations seemed to be different. These results suggest that the reciprocal regulations of cell growth and hepatocyte-specific functions are mediated by some surface components via cell-cell contact.

Acetates↗
PubMed2006

Does impaired executive functioning differentially impact verbal memory measures in older adults with suspected dementia?

The purpose of this study was to examine whether executive dysfunction differentially impacts list-learning and story recall tasks in a sample of older adults referred for suspected cognitive impairment. Older adults (N = 61) with mild cognitive impairment (MCI) or probable mild dementia, and those who did not meet criteria for diagnosis of dementia, were assessed using measures of executive function and verbal memory. Two groups were established based on performance on measures of executive function: (a) the No Executive Dysfunction group (NoED; n = 33) consisted of persons without impairment on any obtained measures of executive function; and (b) the Executive Dysfunction group (ED; n = 28) contained persons with impairment on at least one of the measures of executive function. The two groups were compared on performance on two measures of verbal memory, the California Verbal Learning Test-II (CVLT-II) and the Logical Memory (LM) subtest from the Wechsler Memory Scale-Revised (WMS-R). The NoED group performed significantly better than the ED group on the total learning and short delay free recall trials of the CVLT-II. However, there were no significant differences between the groups on the other indices of the CVLT-II (i.e., long delay free recall, recognition, recall repetitions, recall intrusions, or recognition false-positives) or on the immediate and delayed recall trials of the LM measure. These results support previous research demonstrating the impact of executive dysfunction on the acquisition of and short-delay retrieval of verbal information in older adults with suspected cognitive impairment.

Aged↗
PubMedDate not supplied

Maintenance of differentiated function of the surfactant system in human fetal lung type II epithelial cells cultured on plastic.

We report a simplified culture system for human fetal lung type II cells that maintains surfactant expression. Type II cells isolated from explant cultures of hormone-treated lungs (18-22 wk gestation) by collagenase + trypsin digestion were cultured on plastic for 4 days in serum-free medium containing dexamethasone (Dex, 10 nM) + 8-bromo-cAMP (0.1 mM + isobutylmethylxanthine (0.1 mM) or were untreated (control). Surfactant protein (SP) mRNAs decreased markedly in control cells between days 1 and 4 of culture, but mRNA levels were high in treated cells on day) 4 (SP-A, SP-B, SP-C, SP-D; 600%, 100%, 85%, 130% of day 0 content, respectively). Dex or cAMP alone increased SP-B, SP-C, and SP-D mRNAs and together had additive effects. The greatest increase in SP-A mRNA occurred with cAMP alone. Treated cells processed pro-SP-B and pro-SP-C proteins to mature forms and had a higher rate of phosphatidylcholine (PC) synthesis (2-fold) and higher saturation of PC (approximately 34% versus 27%) than controls. Only treated cells maintained secretagogue-responsive phospholipid synthesis. By electron microscopy, the treated cells retained lamellar bodies and extensive microvilli. We conclude that Dex and cAMP additively stimulate expression of surfactant components in isolated fetal type II cells, providing a simplified culture system for investigation of surfactant-related, and perhaps other, type II cell functions.

1-Methyl-3-isobutylxanthine↗
PubMed2002

Identification of transcripts expressed under functional differentiation in primary culture of cerebral cortical neurons.

In this study, we utilized primary cultures of cerebral cortical neurons and RNA arbitrarily primed polymerase chain reaction (RAP-PCR) to identify differentially expressed transcripts in neurons of different culture ages. Eleven cDNA fragments with high sequence similarity to known genes and Expressed Sequence Tags (ESTs) were cloned. From the National Center for Biotechnology Information (NCBI) sequence database, two clones were shown to be identical to known sequences, Mus musculus HP1-BP74 protein mRNA and Mus musculus KRAB-containing zinc finger protein, both were up-regulated. These genes have never before been shown to be involved in neuronal functional maturation. Among the remaining clones, clone 8-14 (239 bp) was very similar to Rattus norvegicus rS-Rex-b mRNA, which was further confirmed by sequencing its shortest isoform (1.5 kb) obtained by computer cloning. This study has identified eleven potential genes and transcripts, which might be involved in the development and differentiation of GABAergic neurons in culture.

Animals↗
PubMed1990

[Epidermal growth factor receptor (EGF-R) in human breast cancer--a marker of morphologic-functional differentiation].

Epidermal growth factor and some related mitogens elicit a biological response in normal and malignant cells by mediation of a specific receptor, the epidermal growth factor receptor (EGF-R). In recent publications the expression of this receptor, a glycoprotein with extensive sequence homology to the erb B-oncogene, has in human breast carcinoma, been claimed to be an excellent indicator of a poor prognosis, superior to conventional prognostic factors such as nodal status and tumour size. To learn about the functional and prognostic role of EGF-R in breast carcinoma, we screened breast cancer tissue from 91 patients for the expression of the receptor by immunohistochemical means, with a monoclonal antibody. The results were compared to the expression of steroid receptors and to morphological and clinical parameters. We detected EGF-R in normal squamous cells of the skin and in epithelial and myoepithelial cells in non-neoplastic lobuli and ducts of the human breast. EGF-R was found in breast cancer tissues of 22 of the 91 patients. Specific staining was observed mainly in the cell membranes, but also to some extent in the cytoplasm. The distribution pattern of the antigen in terms of intensity of staining and number of specifically stained cells varied widely among different and within different regions of the same tumours.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1998

Two MCAT elements of the SM alpha-actin promoter function differentially in SM vs. non-SM cells.

Transcriptional activity of the smooth muscle (SM) alpha-actin gene is differentially regulated in SM vs. non-SM cells. Contained within the rat SM alpha-actin promoter are two MCAT motifs, binding sites for transcription enhancer factor 1 (TEF-1) transcriptional factors implicated in the regulation of many muscle-specific genes. Transfections of SM alpha-actin promoter-CAT constructs containing wild-type or mutagenized MCAT elements were performed to evaluate their functional significance. Mutation of the MCAT elements resulted in increased transcriptional activity in SM cells, whereas these mutations either had no effect or decreased activity in L6 myotubes or endothelial cells. High-resolution gel shift assays resolved several complexes of different mobilities that were formed between MCAT oligonucleotides and nuclear extracts from the different cell types, although no single band was unique to SM. Western blot analysis of nuclear extracts with polyclonal antibodies to conserved domains of the TEF-1 gene family revealed multiple reactive bands, some that were similar and others that differed between SM and non-SM. Supershift assays with a polyclonal antibody to the TEF-related protein family demonstrated that TEF-1 or TEF-1-related proteins were contained in the shifted complexes. Results suggest that the MCAT elements may contribute to cell type-specific regulation of the SM alpha-actin gene. However, it remains to be determined whether the differential transcriptional activity of MCAT elements in SM vs. non-SM is due to differences in expression of TEF-1 or TEF-1-related proteins or to unique (cell type specific) combinatorial interactions of the MCAT elements with other cis-elements and trans-factors.

Actins↗
PubMedDate not supplied

[Macrophages and the functional differentiation of thymocytes (a review of the authors' own data)].

Cellular, humoral, and genetic mechanisms of induction of T-effectors of the transplant vs. host reaction (THR) have been studied in two-cell culture of phagocyte mononuclears and thymocytes. A direct physical contact and similarity of H-2K locus of major histocompatibility complex between the cooperating cells in culture is required for successful induction of T-effectors of THR. Contact interaction of macrophages with thymocytes leads to accumulation of a 67 KDa humoral factor in the culture medium. Incubation of intact thymocytes with this factor leads to functional transformation of immature thymocytes into corresponding effector cells. Similarity of H-2K locus of the factor producers and intact lymphocytes is also required for successful humoral induction of the T-effectors. The surface H-2K antigen is able to induce formation of THR t-effectors from non-reactive thymocytes. The H2-K-specific mediator, affinity-isolated from the supernatant of the macrophage-thymocyte culture can also cause this induction.

Animals↗
PubMed2004

Functional differentiation within the medial temporal lobe in the rat.

The structures that comprise the medial temporal lobe (MTL) have been implicated in learning and memory. The question of primary concern in the present research was whether the group of anatomically related structures (hippocampus, subiculum, presubiculum/parasubiculum, entorhinal cortex, perirhinal/postrhinal cortex) are involved in mediating a similar memory process or whether the individual structures are differentially involved in memory processes and/or in handling various types of information. A series of five experiments were carried out that involved selectively lesioning the main MTL structures and testing each animal on radial-maze tasks and procedures that provided measures of two different memory processes (reference memory, working memory) and the utilization of two kinds of information (spatial, nonspatial). The structures were found to differ functionally, with the hippocampus and the presubiculum/parasubiculum being especially involved in processing spatial information, and the perirhinal/postrhinal cortex having a specific role in remembering information over a brief time period (working memory). Lesions of the entorhinal cortex failed to affect consistently either memory process or type of information handled, but they did result in impairments in learning the complex spatial discrimination requiring reference memory and in working memory involving nonspatial information. The pattern of behavioral impairments resulting from damage to these discrete MTL structures suggests that several of the structures make unique contributions to learning and memory.

Animals↗
PubMed1997

Differential function of CD80- and CD86-transfected human melanoma cells in the presence of IL-12 and IFN-gamma.

Introduction of co-stimulatory molecules like CD80 and CD86 represents a means to augment the immunogenicity of tumor cells and to induce immune responses directed at tumor antigens. Here we compared CD80- and CD86-transfected human melanoma cells to induce primary immune responses by their capacity to promote proliferation of human allogeneic resting T lymphocytes. CD80- and CD86-transfected SkMel63 melanoma cells induced T cell activation to a comparable degree, which was found to be independent of the cell surface density of these co-stimulatory molecules. Co-expression of CD80 and CD86 did not result in a synergistic increase in T cell proliferation. Both CD80 and CD86 transfectants induced the proliferation of isolated CD4+ or CD8+ T cells. Exogenous IL-2, IL-4 and tumor necrosis factor-alpha respectively enhanced primary T cell proliferation independent of CD80 or CD86 expression. Interestingly, differential activities of CD80 and CD86 were observed following stimulation of resting T cells in the presence of IL-12. Whereas IL-12 increased T cell proliferation in the presence of CD86-transfected melanoma cells, it exhibited an inhibitory function in the presence of CD80-expressing SkMel63 cells. Experimental evidence indicates that this inhibitory effect was mediated by IFN-gamma since (I) IFN-gamma secretion of stimulated T cells was augmented by IL-12, (II) exogenous IFN-gamma also inhibited T cell proliferation induced by CD80- but not CD86-transfected SkMel63 cells and (III) the inhibitory effect of IL-12 was blocked by an anti-IFN-gamma mAb.

Antigens, CD↗
PubMed1982

Genetic stability of differentiated functions in Streptomyces hygroscopicus in relation to conditions of continuous culture.

The genetic stability of the capacity of an improved strain of Streptomyces hygroscopicus to produce the macrolide antibiotic turimycin was investigated during long-term continuous culture. Dilution rate, growth-limiting substrate and culture temperature were varied. Certain culture conditions resulted in the stable propagation of the inoculated turimycin-producing population. Other conditions led to segregation of the initial population. Turimycin non-producing phenotypes appeared, and in each case the simultaneous loss of ability to form aerial mycelium was observed. The non-differentiating clones were found to be stable, without any reversion to the parental phenotype, indicating that a loss of genetic information probably took place.

Ammonium Chloride↗
PubMed1992

Adrenal scintigraphy of well-differentiated (functioning) adrenocortical carcinomas: potential surgical pitfalls.

Adrenal scintigraphy with 131I-6 beta-iodomethylnorcholesterol (NP-59) has been widely used to evaluate adrenal cortical tumors during the past 20 years. Unilateral visualization on the side of an adrenal tumor has been considered diagnostic of a benign adrenocortical adenoma in the patient with Cushing's syndrome. Bilateral nonvisualization of the adrenal glands in the presence of Cushing's syndrome is considered diagnostic of adrenocortical carcinoma (ACC). ACCs characteristically are unable to incorporate enough NP-59 to be visualized on NP-59 adrenal scintigraphy. Two patients with well-differentiated cortisol-secreting ACCs, in which the primary tumor or subsequent metastases demonstrated intense uptake (visualization) on NP-59 scans are reported here. As a result of these findings on NP-59 adrenal scintigraphy, the lesions were initially misinterpreted to represent benign disease. In each patient the operative approach selected, based on the interpretation of the NP-59 scan, was inappropriate for the management of the respective adrenal neoplasm or its metastasis. A review of the literature reveals 16 other cases of either ACC or their metastases that were visualized with adrenal scintigraphy. Ninety percent of these cases were associated with adrenocortical hormone hypersecretion. It is concluded that in the presence of Cushing's syndrome or another adrenocortical hormone excess state, unilateral visualization of an adrenal tumor on NP-59 scintigraphy cannot be interpreted to represent uniformly benign disease.

Adosterol↗