Journal of Cellular Physiology

The effect of transforming growth factor β1 (TGFβ1) on the proliferative response of aortic smooth muscle cells (SMC) in vitro was investigated. TGFβ1 substantially inhibited the growth of human and bovine SMC. Rapidly growing SMC and quiescent serum‐stimulated SMC were inhibited by TGFβ1 with an ID₅₀ of approximately 0.5 ng/ml and maximal inhibition was observed at 10 ng/ml TGFβ1. In the presence of TGFβ1, quiescent serum‐stimulated SMC progress into the G1 phase of the cell cycle, but become reversibly arrested at a point temporally located 1–2 hours from S phase. Release from this late G1 TGFβ1 arrest point results in S phase entry within 2 hours. Associated with this inhibitory effect is a decrease in the histone H1 kinase activity of p34^cdc2 protein kinase while TGFβ1 has no effect on the transcription or translation of p34^cdc2. Under these growth inhibitory conditions, TGFβ1 is still capable of upregulating the expression of fibronectin mRNA. These results suggest that TGFβ1 growth inhibition in SMC is associated with the regulation of p34^cdc2 activity in late G1. © 1993 Wiley‐Liss, Inc.

Most post‐herpetic neuralgia (PHN) patients suffer from tactile allodynia (pain evoked by lightly touching the skin) and it is frequently the dominant clinical manifestation. The pathophysiology of tactile allodynia in PHN patients is poorly understood and this is one of the major limits to the development of appropriate therapies. Epidermal nerve fibres (ENFs) are free nerve endings of small‐diameter A‐delta and C primary afferents, which can easily be assessed by neurodiagnostic skin biopsy (NSB). The aim of this study was to establish the correlation between the residual epidermal innervation of the allodynic skin and the intensity of tactile allodynia in that area. Twenty‐five patients (13 males and 12 females) with PHN were enrolled. Eighteen patients had PHN in the thoracic dermatome, four in the cervical, two in the trigeminal and one in the lumbar. The severity of allodynia evoked by a paintbrush was graded according to an eleven‐point numerical scale. A skin biopsy was obtained from the maximal allodynia area and from the contralateral skin. Nerve fibres were labelled with indirect immunofluorescence. Results showed that epidermal innervation was lower in the allodynic skin than in the contralateral skin, although there was great variability among patients. There was no correlation between severity of allodynia and epidermal innervation of the PHN skin. In conclusion, the present study further indicates peripheral nervous system involvement in PHN but does not support a direct correlation between epidermal innervation changes and tactile allodynia. J. Cell. Physiol. 227: 934–938, 2012. © 2011 Wiley Periodicals, Inc.

Transforming growth factor β (TGFβ) is a family of important regulators of chondrocyte growth and differentiation. Although TGFβ has been detected in cartilage, the TGFβ isoforms expressed by chondrocytes and their regulation by growth factors are unknown. This study shows that human articular chondrocytes release TGFβ activity. Chondrocyte conditioned media contains active TGFβ and larger quantities in latent form. By neutralization with specific antibodies it is shown that all three isoforms (TGFβ1, TGFβ2, and TGFβ3) are secreted by chondrocytes. Analysis of the inducers of TGFβ gene expression demonstrates complex regulation of TGFβ production by growth factors. Basic fibroblast growth factor (bFGF) stimulates the release of TGFβ activity but has no effect on steady state TGFβ mRNA levels while platelet‐derived growth factor (PDGF) upregulates TGFβ1 and TGFβ3 mRNAs with a corresponding increase in protein secretion. The three TGFβ isoforms themselves differentially affect gene expression. While TGFβ1 and TGFβ2 show autoinduction, TGFβ3 upregulates TGFβ1 but does not affect TGFβ2 mRNA levels.

These results demonstrate that human articular chondrocytes produce all three TGFβ isoforms. Induction of TGFβ expression is differentially regulated by various growth factors and occurs at the mRNA level and/or posttranscriptionally. Chondrocyte expression and the differential regulation of TGFβ1, TGFβ2, and TGFβ3 by growth factors suggest that all three isoforms of TGFβ are part of the network of cartilage regulatory factors. © 1992 Wiley‐Liss, Inc.

Experiments have been carried out on the capping by lectins and antibodies of surface receptors of mouse splenic T and B lymphocytes and other cells, in which the surface distribution of the lectin or antibody, and the intracellular distribution of myosin or actin, were determined on the same cells by a double fluorescence technique. For this purpose, a general method for intracellular staining was developed which is intended to preserve sensitive antigens and fragile ultrastructural elements. The method involves mild formaldehyde fixation of the cells or tissues, infusion with concentrated sucrose, rapid freezing, and the preparation of frozen sections thinner than 2 μm thickness. The immunofluorescent or other appropriate fluorescent reagents are then applied to the thawed section. In the present experiments, intracellular actin was detected using a fluorescent staining method based on the interaction of F‐actin with heavy meromyosin, while intracellular myosin was detected by an indirect immunofluorescence procedure. Our findings were that the formation of a cap by each of the lectins or antibody reagents was always accompanied by a concentration of myosin and actin directly under the cap. These and other results suggest that capping is an active process in which actin and myosin participate directly in the formation of all caps. This proposal carries important new implications for the molecular mechanism of capping.

We set out to identify pharmacological means by which to activate the so‐called heat shock or stress response and thereby harness the protective effect afforded to the cell by its acquisition of a thermotolerant phenotype. An earlier report by Murakami et al. (1991, Exp. Cell Res., 195: 338–344) described the increased expression of the 70 kDa heat shock proteins in human A431 cells exposed to Herbimycin A (HA), a benzoquinoid ansamycin antibiotic. We show here that treatment of cells with HA results in the increased expression of all of the constitutively expressed stress proteins and confers upon the cells a thermotolerant‐like phenotype. Increases in the expression of the stress proteins continued for as long as the cells were exposed to the drug and was independent of the pre‐existing levels of the stress proteins. Unlike heat shock or other metabolic stressors, we did not observe any adverse cellular effects following HA exposure. For example, unlike most agents/treatments that elicit the stress response HA‐treated cells exhibited no obvious abnormalities with respect to protein maturation, protein insolubility, the integrity of the intermediate filament cytoskeleton, or overall cell viability. In addition, unlike other metabolic stressors, HA treatment did not result in the translocation of hsp 73 into the nucleus/nucleolus. Finally, for at least rodent cells, HA exposure did not result in any obvious activation of the heat shock transcription factor. Based on these findings, we suggest that HA treatment of cells results in a “short‐circuiting” of the pathway(s) that normally regulates the expression of the stress proteins. These results are discussed as they pertain to the potential use of HA in animals as a way to harness the protective effects afforded by the stress response. © 1995 Wiley‐Liss Inc.

A system for fractionating populations of living cells by velocity sedimentation in the earth's gravitational field is described. The cells start in a thin band near the top of a shallow gradient of 3% to 30% fetal calf serum in phosphate buffered saline at 4°C. Cell separation takes place primarily on the basis of size and is approximately independent of cell shape. A sharply‐defined upper limit, called the streaming limit, exists for the cell concentration in the starting band beyond which useful cell separations cannot be achieved. This limit, which varies with the type of cell being sedimented, can be significantly increased by proper choice of gradient shape. For sheep erythrocytes (sedimentation velocity of 1.6 mm/hour) it is 1.5 × 10⁷ cells/ml. Measured and calculated sedimentation velocities for sheep erythrocytes are shown to be in agreement. The technique is applied to a suspension of mouse spleen cells and it is shown, using an electronic cell counter and pulse height analyzer, that cells are fractionated according to size across the gradient such that the sedimentation velocity (in mm/hour) approximately equals r²/4 where r is the cell radius in microns. Since cells of differing function also often differ in size, the system appears to have useful biological applications.

Tumors tend to metastasize to the liver. Premetastatic niche formation is a vital step in liver metastasis. Tumor‐derived exosomes can influence premetastatic niche formation from three aspects: vascular leakiness and angiogenesis, recruitment of nonresident cells, and changes in local resident cells. Exosomes from other tissues, such as mesenchymal stem cell‐derived exosomes and engineered exosomes, also have therapeutic potential, but further research on these exosomes is required. Based on the mechanism of premetastatic niche formation, we summarize the therapeutic and diagnostic potential of exosomes in inhibiting liver metastases in this review in an attempt to provide new avenues for the prevention and treatment of liver metastases.

Almost 90% of nephrogenic diabetes insipidus (NDI) is due to mutations in the arginine‐vasopressin receptor 2 gene (AVPR2). We retrospectively examined all the published mutations/variants in AVPR2. We planned to perform a comprehensive review of all the AVPR2 mutations/variants and to test whether any amino acid change causing a missense mutation is significantly more or less common than others. We performed a Medline search and collected detailed information regarding all AVPR2 mutations and variants. We performed a frequency comparison between mutated and wild‐type amino acids and codons. We predicted the mutation effect or reported it based on published in vitro studies. We also reported the ethnicity of each mutation/variant carrier. In summary, we identified 211 AVPR2 mutations which cause NDI in 326 families and 21 variants which do not cause NDI in 71 NDI families. We described 15 different types of mutations including missense, frameshift, inframe deletion, deletion, insertion, nonsense, duplication, splicing and combined mutations. The missense mutations represent the 55.83% of all the NDI published families. Arginine and tyrosine are significantly (P = 4.07E−08 and P = 3.27E−04, respectively) the AVPR2 most commonly mutated amino acids. Alanine and glutamate are significantly (P = 0.009 and P = 0.019, respectively) the least mutated AVPR2 amino acids. The spectrum of mutations varies from rare gene variants or polymorphisms not causing NDI to rare mutations causing NDI, among which arginine and tyrosine are the most common missense. The AVPR2 mutations are spread world‐wide. Our study may serve as an updated review, comprehensive of all AVPR2 variants and specific gene locations. J. Cell. Physiol. 217: 605–617, 2008. © 2008 Wiley‐Liss, Inc.