Induction of tissue transglutaminase and apoptosis by retinoic acid in the limb bud

Mesenchymal cells in the limb buds of midgestation mouse embryos suffer prominent cell death upon exposure to retinoic acid (RA), an event likely associated with the micromelic and phocomelic anomalies of the resultant fetuses. It has been suggested, but not yet shown, that cells die by an active process termed apoptosis rather than by necrotic cytolysis. In certain cell types, investigators have previously observed a specific and early effect of RA on transcriptional activation of the gene for tissue transglutaminase (tTG), an enzyme suspected to play a role in apoptosis. We report here a distinct but transient increase in tTG activity which accompanied the initiation of cell death in the mesenchymal cells located in the central core of RA-treated limb buds. We also ascertained microscopically that the cytological appearance of the affected cells was consistent with a characterization of the process of cell death as apoptosis.

Protein kinase C-dependent and -independent actions of a potent protein kinase C inhibitor, staurosporine

12-O-Tetradecanoylphorbol 13-acetate (TPA), an activator of protein kinase C (PKC), induced ornithine decarboxylase (ODC) in primary cultured mouse epidermal cells. Staurosporine, a potent protein kinase C inhibitor, also induced ODC activity. Both TPA- and staurosporine-caused ODC inductions were markedly suppressed in the PKC-down-regulated cells. Another PKC inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), inhibited both TPA- and staurosporine-caused ODC inductions. H-7 by itself never induced ODC activity. Under our experimental conditions, staurosporine induced no detectable phosphorylation of endogenous proteins. TPA induced a translocation of PKC from cytosol to membrane whereas an optimal concentration of staurosporine to induce ODC did not induce an obvious translocation of PKC. Indomethacin, a cyclooxygenase inhibitor, inhibited staurosporine-caused ODC induction, but not TPA-caused ODC induction. Staurosporine induced specific morphological changes of epidermal cells both in normal and in PKC-down-regulated cells. These results indicate that staurosporine induces ODC activity in a PKC-dependent manner and morphological changes possibly through a PKC-independent mechanism. The mechanism of ODC induction caused by staurosporine may be in some way different from that caused by TPA.

Tumor target-derived soluble factor synergizes with IFN-gamma and IL-2 to activate macrophages for tumor necrosis factor and nitric oxide production to mediate cytotoxicity of the same target

Inflammatory mouse peritoneal macrophages were activated by IFN-gamma in synergy with IL-2 or Lipid A to mediate TNF production for autocrine generation of cytotoxic nitric oxide (NO) to kill P815 or L1210 tumor targets. It was determined that for IL-2, but not Lipid A, to effectively trigger activation of IFN-gamma-primed macrophages, the tumor targets must be also present for interaction with effector macrophages to mediate the production of TNF and NO. IFN-gamma- and IL-2-activated macrophages from syngeneic DBA/2 and allogeneic C3H mice had identical MHC-unrestricted requirements for interaction with DBA/2 mouse-derived P815 and L1210 targets to mediate production of TNF and NO for tumor cytotoxicity. To further define the mechanistic requirements for macrophage-tumor target interaction, IFN-gamma- and IL-2-activated macrophages were separated from P815 targets in culture by a semipermeable membrane. Under these conditions, both TNF and NO were produced by the macrophage, which indicated that the requirement for tumor target-macrophage interaction may be due to a soluble factor produced by the target rather than to direct physical contact. This was confirmed by experiments in which 24-h cell-free culture fluids, derived from either P815 or L1210 tumor targets, substituted for the intact tumor cells in the stimulation of TNF mRNA synthesis and secretion with NO generation of TNF mRNA synthesis and secretion with NO generation by IFN-gamma- and IL-2-activated C3H or DBA/2 macrophages. The activity in 24-h culture fluids derived from P815 and L1210 tumor targets was tentatively designated as tumor-derived recognition factor(s) (TDRF) since it was produced constitutively by the tumor targets and synergized with IFN-gamma and IL-2 to induce macrophage production of TNF and NO for death of the same targets. A variety of nontransformed human and mouse fibroblasts, mouse spleen lymphocytes, and two adherent mouse fibrosarcomas did not produce detectable TDRF activity, whereas two mouse T lymphomas, EL4 and EL4.IL-2, produced TDRF activity similar to L1210 mouse leukemia and P815 mastocytoma. The C3H/MCA, a TDRF-nonproducing mouse fibrosarcoma, was susceptible to cytotoxicity mediated by macrophages activated by IFN-gamma and Lipid A, but not by IL-2 triggering. Exogenous TDRF derived from L1210 targets reconstituted the cytotoxic activity for C3H/MCA MCA targets mediated by IFN-gamma- and IL-2-activated macrophages accompanied by the production of TNF and cytotoxic NO.(ABSTRACT TRUNCATED AT 400 WORDS)

Tumor target-derived soluble factor synergizes with IFN-gamma and IL-2 to activate macrophages for tumor necrosis factor and nitric oxide production to mediate cytotoxicity of the same target

Inflammatory mouse peritoneal macrophages were activated by IFN-gamma in synergy with IL-2 or Lipid A to mediate TNF production for autocrine generation of cytotoxic nitric oxide (NO) to kill P815 or L1210 tumor targets. It was determined that for IL-2, but not Lipid A, to effectively trigger activation of IFN-gamma-primed macrophages, the tumor targets must be also present for interaction with effector macrophages to mediate the production of TNF and NO. IFN-gamma- and IL-2-activated macrophages from syngeneic DBA/2 and allogeneic C3H mice had identical MHC-unrestricted requirements for interaction with DBA/2 mouse-derived P815 and L1210 targets to mediate production of TNF and NO for tumor cytotoxicity. To further define the mechanistic requirements for macrophage-tumor target interaction, IFN-gamma- and IL-2-activated macrophages were separated from P815 targets in culture by a semipermeable membrane. Under these conditions, both TNF and NO were produced by the macrophage, which indicated that the requirement for tumor target-macrophage interaction may be due to a soluble factor produced by the target rather than to direct physical contact. This was confirmed by experiments in which 24-h cell-free culture fluids, derived from either P815 or L1210 tumor targets, substituted for the intact tumor cells in the stimulation of TNF mRNA synthesis and secretion with NO generation of TNF mRNA synthesis and secretion with NO generation by IFN-gamma- and IL-2-activated C3H or DBA/2 macrophages. The activity in 24-h culture fluids derived from P815 and L1210 tumor targets was tentatively designated as tumor-derived recognition factor(s) (TDRF) since it was produced constitutively by the tumor targets and synergized with IFN-gamma and IL-2 to induce macrophage production of TNF and NO for death of the same targets. A variety of nontransformed human and mouse fibroblasts, mouse spleen lymphocytes, and two adherent mouse fibrosarcomas did not produce detectable TDRF activity, whereas two mouse T lymphomas, EL4 and EL4.IL-2, produced TDRF activity similar to L1210 mouse leukemia and P815 mastocytoma. The C3H/MCA, a TDRF-nonproducing mouse fibrosarcoma, was susceptible to cytotoxicity mediated by macrophages activated by IFN-gamma and Lipid A, but not by IL-2 triggering. Exogenous TDRF derived from L1210 targets reconstituted the cytotoxic activity for C3H/MCA MCA targets mediated by IFN-gamma- and IL-2-activated macrophages accompanied by the production of TNF and cytotoxic NO.(ABSTRACT TRUNCATED AT 400 WORDS)

Retinoic acid receptor beta 2 mRNA is elevated by retinoic acid in vivo in susceptible regions of mid-gestation mouse embryos

Many of the biological effects of retinoic acid are mediated by its nuclear receptors (RAR-alpha, RAR-beta, and RAR-gamma), and each of these three receptors exist in multiple isoforms. As a first step to identify if any of the receptor isoforms are involved in dysmorphogenesis which is induced in mouse embryos after treatment with retinoic acid (RA), we examined the levels of mRNA of several isoforms of each RAR in the limb buds and other embryonic regions of normal and RA-treated embryos. Within 3 to 6 hr after treatment of mice on day 11 of gestation with RA, RAR-beta 2 mRNA levels in the whole embryo increased 7-fold while both RAR-alpha 2 and RAR-gamma 1 mRNA levels were elevated only 2-fold. Since RA treatment of day 11 embryos especially produces limb defects in virtually every embryo, we next examined individual embryonic regions separately. Limb buds showed the highest elevations in RAR-beta 2 mRNA levels (12-fold) compared to a moderate elevation in the head/craniofacial region (8-fold) and a small elevation in the remainder of the body (4-fold). In contrast, RAR-alpha 2 and RAR-gamma 1 mRNA levels were elevated in all these tissues to a similar extent, which amounted to only about a 2-fold increase. Retinol, the precursor of RA in the embryo, was also capable of elevating RAR-beta 2 mRNA levels in the limb bud, but the increase was delayed, apparently indicating that metabolic conversion of retinol to RA preceded the effect on mRNA levels.(ABSTRACT TRUNCATED AT 250 WORDS)

[Microneurovascular free abductor hallucis muscle transplantation for resuscitation of facial paralysis in one stage]

After study of local anatomy in fresh cadaver the authors carried out free abductor hallucis muscle transplantation successfully in three patients with facial paralysis. In one patient the plantaris medialis vessels were anastomosed to the contralateral facial vessels and the plantaris medialis nerve was anastomosed to buccal branch of the contralateral facial nerve. In two patients the plantaris medialis vessels were anastomosed to the ipsilateral facial vessels and the plantaris medialis nerve was anastomosed to the myloidens branch from ipsilateral trigeminal nerve. The authors described the local anatomy and operative methods in details. The advantages of this operative method were also discussed.

In vivo and in vitro mechanisms of cardiac allograft acceptance in the rat after short treatment with 15-deoxyspergualin

15-Deoxyspergualin (DSG) has been reported to be a useful immunosuppressive agent already used to inhibit acute rejection in clinical transplantation. In the present study, the survival of heart allograft in rats after a short course of DSG treatment and the mechanisms underlying DSG-induced heart allograft acceptance were studied. Male LEW rats were used as recipients. Male ACI and Wistar rats were used as donors and third-party donors, respectively. Survival of ACI heart grafts in LEW recipients treated with a short course of DSG starting on day 4 after grafting was markedly prolonged, with a mean survival time of 16.6 +/- 5.8 days and 29.8 +/- 3.0 days at doses of 2.5 mg/kg per day and 5 mg/kg per day, respectively. On day 20 after grafting, the mechanism of inducing allograft survival after DSG treatment at a dose of 5 mg/kg per day was analyzed by testing the activation of spleen cells or serum in several assay systems. Spleen cells from DSG-treated rats with surviving heart allografts showed almost no proliferative response against donor strain stimulator cells compared with controls. The cytotoxic activity towards donor strain target cells of spleen cells from DSG-treated rats with surviving heart allografts was lower than that of spleen cells from rats with rejected heart allografts.(ABSTRACT TRUNCATED AT 250 WORDS)

[Double filtration plasma pheresis was effective on the recurrence of pulmonary hemorrhage after renal transplantation: report of a case]

A 35-year old female with an autoimmune disease complaining of recurrent hemoptysis and macrohematuria had received a renal transplantation from her mother. After transplantation, recurrence of pulmonary hemorrhage occurred twice. First recurrence followed the peritonitis with ileal perforation. Steroid pulse therapy had no effect on this recurrence, while double filtration plasmapheresis was effective. During this treatment, renal function was not failed. Second recurrence followed acute rejection that was cured with the OKT3-rescue therapy. DFPP therapy was effective on this episode. Pulmonary hemorrhage was caused by auto immune reaction and acute rejection caused by transplant immune reaction were recognized independently, and they needed different treatment. According to this clinical course, we consider the relation between auto immune reaction and transplant immune reaction was as follows. T cell activation caused by primary transplant immune reaction may have no direct influence on auto immune reaction. Peritonitis and rejection may induce auto immune reaction. We suppose that this auto immune reaction was caused by humoral factor, because auto immune reaction was controlled by DFPP.

Reactivity of anti-human C-reactive protein (CRP) and serum amyloid P component (SAP) monoclonal antibodies with limulin and pentraxins of other species

Limulus polyphemus C-reactive protein (CRP) (limulin) has approximately 30% amino acid sequence homology and shares at least one idiotypic determinant associated with ligand-binding activity with human CRP (hCRP); limulin also shares amino acid sequence homology and lectin activity with human serum amyloid P component (hSAP). In the present study panels of 14 anti-hCRP monoclonal antibodies (mAb) directed to distinct hCRP epitopes and 11 anti-hSAP mAb directed to distinct epitopes of hSAP were tested for reactivity with limulin and pentraxins of other species including rabbit CRP (raCRP), rat CRP and hamster female protein (FP) by ELISA and Western blot analyses. None of the anti-human pentraxin mAb showed strong cross-reactivity with limulin; only five mAb reacted with limulin at all, and cross-reactivities of these mAb with the other pentraxins, when present, also were weak. Cross-reactivity of limulin with hCRP and hSAP was similar, and in light of comparable amino acid sequence homology, suggests this molecule can be considered the limulus SAP as well as the limulus CRP. Several anti-hCRP mAb cross-reacted strongly with rabbit CRP and rat CRP; a few anti-hSAP cross-reacted strongly with FP; and weak cross-reactions were observed between hCRP and hSAP, but cross-reactivities between the pentraxins generally were limited and weak. A rabbit polyclonal antibody raised to highly conserved limulin peptide 141-156 and strongly reactive with limulin reacted weakly with hCRP and raCRP but failed to react with rat CRP, hSAP or FP. These studies emphasize a limited but distinct antigenic similarity between limulin, hCRP and other pentraxins, and identify mAb reactive with potential regions of shared structure and/or function between pentraxins of different species.

[Acceleration of epidermis proliferation by direct current stimulation (an experimental study)]

An experimental study was designed to evaluate the effect of direct current stimulation on the rate of epidermis proliferation using guinea pigs. In the study, two full thickness skin defects were made over the paravertebral region in each animal. The edges of wounds were transfixed. One of the wounds in each animal received the DC stimulation, and the other did not. The 44 animals were divided into four groups of eleven animals each, the stimulation strengths were 10 muADC, 30 muADC, 50 muADC, 0 muADC respectively. The results showed that the rate of epidermal cell proliferation and wound healing with the DC stimulation were faster, especially on the side of the negative electrode, and the rate of healing of the unstimulated wound in animals which received stimulation in the contralateral wound was faster than that of wounds of control animals.

Induction of growth suppression and modification of gene expression in multi-drug-resistant human glioblastoma multiforme cells by recombinant human fibroblast and immune interferon

The combination of recombinant human fibroblast (IFN-beta) and immune (IFN-gamma) interferon induces enhanced growth suppression and modifies the antigenic phenotype in parental and multi-drug-resistant (MDR) human glioblastoma multiforme (GBM) cells. The present study was conducted to explore the mechanism underlying this cooperative interaction between interferons in inducing growth suppression in MDR-GBM cells. For this analysis we have utilized 2 MDR-GBM cell lines which display a differential sensitivity to growth suppression when exposed to IFN-beta or IFN-gamma. GBM-18-B3 (MDR) cells are more sensitive to growth inhibition by IFN-gamma than by IFN-beta, whereas GBM-18-A3 (MDR) cells are inhibited to a greater degree by IFN-beta than by IFN-gamma. In both cell types, however, growth is suppressed to a greater degree by the combination of interferons than by equivalent concentrations of either type of interferon used alone. Growth suppression induced by the interferons, alone or in combination, was not associated with comparable changes in the steady-state level of MDRI mRNA. In addition, the anti-proliferative effect of interferon was similar in GBM-18 (MDR) cells grown in the presence or absence of colchicine. GBM-18-A3 and GBM-18-B3 cells differed in their de novo and interferon-inducible expression levels of IFN-beta-responsive genes, isg-15 and isg-54. In contrast, both cell types responded in a similar manner with respect to expression of the IFN-gamma-responsive gene, HLA Class II (HLA-DR beta), and HLA Class I, fibronectin and ICAM-I. No further increase in expression of any of the genes was observed which was unique to the combination of interferons.

Role of CD8+ T cells in murine experimental allergic encephalomyelitis

The course of experimental allergic encephalomyelitis (EAE), an animal model for multiple sclerosis, is affected by immunoregulatory T lymphocytes. When animals are immunized with encephalitogenic peptide of myelin basic protein and recover from the first episode of EAE, they become resistant to a second induction of this disease. Animals depleted of CD8+ T cells by antibody-mediated clearance were used to examine the role of CD8+ T cells in EAE. These cells were found to be major participants in the resistance to a second induction of EAE but were not essential for spontaneous recovery from the first episode of the disease.

A phenylalanine in peptide substrates provides for selectivity between cGMP- and cAMP-dependent protein kinases

Bovine lung cGMP-binding cGMP-specific phosphodiesterase (cG-BPDE) is a potent and relatively specific substrate for cGMP-dependent protein kinase (cGK) as compared to cAMP-dependent protein kinase (cAK) (Thomas, M. K., Francis, S. H., and Corbin, J. D. (1990) J. Biol. Chem. 265, 14971-14978). A synthetic peptide, RKISASEFDRPLR (BPDEtide), was synthesized corresponding to the sequence surrounding the phosphorylation site in cG-BPDE. BPDEtide retained the cGK/cAK kinase specificity demonstrated by native cG-BPDE: the apparent Km of BPDEtide for cGK was 5-fold lower than that for cAK (Km = 68 and 320 microM, respectively). Vmax values were 11 mumol/min/mg for cGK and 3.2 mumol/min/mg for cAK. The peptide was not phosphorylated to a measurable extent by protein kinase C or by calcium/calmodulin-dependent protein kinase II. Thus, the primary amino acid sequence of the peptide substrate was sufficient to confer kinase specificity. Studies in crude tissue extracts indicated that BPDEtide was the most selective peptide substrate documented for measuring cGK activity. Peptide analogs of BPDEtide were synthesized to determine the contribution of specific residues to cGK or cAK substrate specificity. Substitution of a Lys for the amino-terminal Arg did not reduce cGK/cAK specificity; neither did the exchange of an Ala for the non-phosphorylated Ser nor the removal of the 3 carboxyl-terminal residues. A truncated BPDEtide (RKISASE) served equally well as substrate (Km approximately 90 microM) for both kinases. However, restoration of the Phe, to yield RKISASEF, reproduced the original cGK/cAK specificity for BPDEtide (Km = 120 and 480 microM, respectively), primarily by decreasing the affinity of cAK. Addition of a carboxyl-terminal Phe to the peptide RKRSRAE (derived from the sequence of the cGK phosphorylation site in histone H2B) or to the peptide LRRASLG (derived from the sequence of the cAK phosphorylation site in pyruvate kinase) also improved the cGK/cAK specificity by decreasing the affinity of cAK. These data suggested that the Phe in each substrate tested is a negative determinant for cAK.

Localization of sites through which C-reactive protein binds and activates complement to residues 14-26 and 76-92 of the human C1q A chain

Studies were initiated to localize the C-reactive protein (CRP) binding site on the collagen-like region (CLR) of C1q. CRP bound preferentially to the A chain of reduced C1q, in contrast to aggregated immunoglobulin G (Agg-IgG), which reacted preferentially with the C chain. A group of C1q A chain peptides, including peptides identical to residues 81-97, 76-92, and 14-26, respectively, were synthesized from predicted binding regions. Peptide 76-92 contained two proximal lysine groups, and peptide 14-26 contained four proximal arginine groups. CRP-trimers and CRP-ligand complexes did not bind to immobilized peptide 81-97, but bound avidly to immobilized peptides 76-92 and 14-26. Agg-IgG did not bind to any of the peptides. Peptide 76-92 partially, and peptide 14-26 completely, inhibited binding of CRP to intact C1q. Peptide 14-26 also blocked C consumption initiated by CRP, but not by IgG. Replacement of the two prolines with alanines, or scrambling the order of the amino acids, resulted in loss of ability of peptide 14-26 to inhibit C1q binding and C activation by CRP, indicating a sequence specificity, and not a charge specificity alone, as the basis for the inhibitory activity of the peptide. Similar investigations with scrambled peptides showed a sequence specificity for the effects of peptide 76-92 as well. DNA and heparin inhibited binding of CRP trimers to intact C1q, as well as to each peptide 14-26 and 76-92, suggesting involvement of these regions in C1q-CLR binding reactions generally. Collectively, these data identify two cationic regions within residues 14-26 and 76-92 of the C1q A chain CLR as sites through which CRP binds and activates the classical C pathway, and suggest that these residues represent significant regions for C1q CLR binding reactions generally. To our knowledge, this represents the first delineation of sites on C1q through which binding and activation of the classical C pathway can occur.

Involvement of prostaglandin E2 in ornithine decarboxylase induction by a tumor-promoting agent, 7-bromomethylbenz[a]anthracene, in mouse epidermis

A single topical application of 7-bromomethyl-benz[a]anthracene (BrMBA; 200 nmol) to mouse skin induced epidermal ornithine decarboxylase (ODC) activity. A topical application of indomethacin (1.2 mumol), a cyclooxygenase inhibitor, 10 min before BrMBA application markedly inhibited BrMBA-caused ODC induction. Concurrent application of prostaglandin E2 (PGE2; 0.1-1.5 mumol) reversed the inhibitory effect of indomethacin. Without indomethacin, PGE2 suppressed BrMBA-caused ODC induction. The results indicate that PGE2 has dual actions on the BrMBA-caused ODC induction, i.e. PGE2 plays an essential role in ODC induction caused by BrMBA, whereas exogenous PGE2 rather suppressed BrMBA-caused ODC induction.

Normalization of contractile parameters in canine airway smooth muscle: morphological and biochemical

Asthma research has recently highlighted the importance of correctly normalizing force development for purposes of comparing stiffness properties of smooth muscle between different airways, between airways at different stages of maturity, and between airways from different animal species. This problem does not exist in striated muscle where the entire tissue consists almost entirely of muscle and where cross bridges cycle at the same rate throughout a contraction when load correlation is made. In the bronchus, cross-sectional area of true muscle may constitute only 20-30% of the total tissue cross section, and load-independent cycling rate varies fourfold during the course of a contraction because of the occurrence of normally cycling and latch bridges. These features are responsible for the difficulty in force normalization in smooth muscle. Our studies indicate that normalization with respect to true muscle cell cross-sectional area (derived by quantitative morphometry of appropriate tissue transverse sections) is the most valid. This is only so, however, when it has been proved that the actomyosin content per unit weight of the different muscle tissues is the same.

The biophysics and biochemistry of smooth muscle contraction

In this review the biophysics and biochemistry of smooth muscle contraction are dealt with. We describe a new model for the study of bronchial smooth muscle, which facilitates study of cellular contractile mechanisms. A new concept emerging is that study of steady-state mechanical parameters such as maximal isometric force (Po) velocity is inadequate because two types of crossbridges (normally cycling (NBR) and latch) seem to be sequentially active during smooth muscle contraction. Thus quick-release techniques are required to characterize the force-velocity properties of the two types of bridges. Pathophysiological processes that affect the muscle's shortening ability seem to affect the early NBRs only. With respect to maximal shortening capacity of the smooth muscle, the role of loading is very important. The differences between isotonic, elastic, and viscous loading are considerable. Ultimately, the time course and magnitude of loading should exactly resemble that operative in vivo. Once again, it is the characteristic of loading in the early phase of contraction that is crucial, as most of the shortening in smooth muscle occurs early in the contraction. While the maximum force developed by smooth muscle per unit cross-sectional area is the same as for striated muscle, the velocity is 50 times less. The properties of the series and parallel elastic elements of smooth muscle are described. The latter, when in compression mode, acts as an internal resistance to shortening and probably limits it. Isotonic relaxation has therefore not been studied in smooth muscle. We have developed a shortening parameter that is independent of the load on the muscle and of the initial length of the muscle's contractile element. We report the novel observation that isotonically relaxing smooth muscle reactivates itself, resulting in terminal slowing of the relaxation process. With respect to the biochemistry of smooth muscle contraction, contractile (actin isoforms, myosin heavy and light chains and their isoforms), regulatory (calmodulin-4 Ca2+, myosin light chain kinase, myosin light chain and its phosphorylation, tropomyosin, caldesmon, and calponin), and cytoskeletal (chiefly desmin and vimentin) proteins are discussed. While the kinase activates the contractile system, caldesmon and calponin modulate the activity downward. The cytoskeletal proteins desmin, vimentin, and alpha-actinin could constitute the muscle cell's internal resistor.