Chemistry and biochemistry of 4-hydroxynonenal, malonaldehyde and related aldehydes.

https://www.cell.com/cell/pdf/0092-8674(93)90509-O.pdf

Bcl-2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programed cell death

Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

The Effects of Plant Flavonoids on Mammalian Cells:Implications for Inflammation, Heart Disease, and Cancer

Publisher Summary This chapter discusses the methods used for the qualitative and quantitative determination of aldehydes in biological systems. It focuses on 4-hydroxynonenal (HNE) and malondialdehyde (MDA). 4-Hydroxynonenal is produced as a major product of the peroxidative decomposition of polyunsaturated fatty acids (PUFA) and possesses cytotoxic, hepatotoxic, mutagenic, and genoroxic properties. Increased levels of HNE are found in plasma and various organs under conditions of oxidative stress. In addition to HNE, lipid peroxidation generates many other aldehydes that may also be of toxicological significance. Malondialdehyde is in many instances the most abundant individual aldehyde resulting from lipid peroxidation, and its determination by thiobarbituric acid (TBA) is one of the most common assays in lipid peroxidation studies. In vitro MDA can alter proteins, DNA, RNA, and many other biomolecules. Recently, it has been demonstrated with monoclonal antibodies that malonaldehyde-altered protein occurs in atheroma of hyperlipidemic rabbits.

Determination of aldehydic lipid peroxidation products: malonaldehyde and 4-hydroxynonenal

Publisher Summary Studies of cytotoxicity by human lymphocytes revealed not only that both allogeneic and syngeneic tumor cells were lysed in a non-MHC-restricted fashion, but also that lymphocytes from normal donors were often cytotoxic. Lymphocytes from any healthy donor, as well as peripheral blood and spleen lymphocytes from several experimental animals, in the absence of known or deliberate sensitization, were found to be spontaneously cytotoxic in vitro for some normal fresh cells, most cultured cell lines, immature hematopoietic cells, and tumor cells. This type of nonadaptive, non-MHC-restricted cellmediated cytotoxicity was defined as “natural” cytotoxicity, and the effector cells mediating natural cytotoxicity were functionally defined as natural killer (NK) cells. The existence of NK cells has prompted a reinterpretation of both the studies of specific cytotoxicity against spontaneous human tumors and the theory of immune surveillance, at least in its most restrictive interpretation. Unlike cytotoxic T cells, NK cells cannot be demonstrated to have clonally distributed specificity, restriction for MHC products at the target cell surface, or immunological memory. NK cells cannot yet be formally assigned to a single lineage based on the definitive identification of a stem cell, a distinct anatomical location of maturation, or unique genotypic rearrangements.

Biology of natural killer cells.

The cDNA sequence for murine interleukin-3, one of the colony stimulating factors that regulate haematopoiesis, codes for a polypeptide of 166 amino acids including a putative signal peptide. The predicted amino acid sequence indicates that formation of mature interleukin-3 involves proteolytic removal of not only the signal peptide but additional ammo-terminal amino acids.

Molecular cloning of cDNA for murine interleukin-3.

Interleukin-3 (multi-CSF) is a multilineage haematopoietic growth regulator that initiates the proliferation and differentiation of multipotential stem cells. Complementary DNA clones encoding interleukin-3 (IL-3) have recently been isolated and the structure of the IL-3 gene determined. IL-3 is produced by T lymphocytes or T lymphomas only after stimulation with antigens, mitogens or chemical activators such as phorbol esters. The myelomonocytic leukaemia line WEHI-3B also produces IL-3 but its production is constitutive and the WEHI-3B cells do not appear to produce significant levels of any of the other lymphokines normally secreted by T lymphocytes after stimulation. It has been proposed that the genetic change leading to the constitutive expression of IL-3 may have been a key event in the development of this leukaemia. We report here that the constitutive synthesis of IL-3 by the WEHI-3B cell line is due to the insertion of an endogenous retrovirus-like element close to the 5' end of the gene. The insertion, an intracisternal A particle (IAP) genome, is positioned with its 5' long terminal repeat (LTR) close to the promoter region of the IL-3 gene, resulting in constitutive synthesis of IL-3.

Constitutive synthesis of interleukin-3 by leukaemia cell line WEHI-3B is due to retroviral insertion near the gene.

It has been recently demonstrated that conditioned media from Con A-stimulated splenocyte cultures contain a novel lymphokine termed IL 3. IL 3 is characterized by its ability to induce 20-alpha-hydroxysteroid dehydrogenase in spleen cells from young nu/nu mice. In search of a convenient source for biochemical and in vivo studies of this lymphokine, a number of established murine cell lines were screened for the constitutive and induced production of Il 3. It was found that WEHI-3 cells, originally designated as a myelomonocyte cell line, produced high levels of IL 3 constitutively. Added mitogen and/or phorbol acetate did not enhance the production of IL 3. Production of IL 3 varied among various sublines of WEHI-3. IL 3 purified from WEHI-3-conditioned media has biochemical and biologic characteristics identical to those obtained from Con A-conditioned media. WEHI-3 conditioned media, however, generally contained 100-fold higher levels of IL 3 than conditioned media from Con A-stimulated splenic lymphocytes.

Constitutive production of a unique lymphokine (IL 3) by the WEHI-3 cell line.

https://www.gastrojournal.org/article/0016-5085(92)90100-D/pdf

Enhanced Mucosal Cytokine Production in Inflammatory Bowel Disease

Much of the regulation of lymphocyte differentiation is unknown. This, in part, has been due to the inability to develop reliable in vitro assays or long-term cultures of lymphocytes. Consequently, many of the current hypotheses concerning the pathways and regulation of lymphocyte differentiation were obtained from complex in vivo experiments. During recent years, however, new techniques and concepts have evolved which may ultimately allow a critical in vitro dissection of the events in lymphocyte differentiation. The concept that lymphokines, as identifiable and purifiable proteins, mediate reactions that were once attributed to complex cell interactions provides a much more amenable approach for ultimate resolution of the basic biology involved. The observation that certain lymphokines have the capability of supporting the proliferation and growth of specific lymphocytes in vitro as an integral component of their physiological functions provides the unique opportunity to isolate specific intermediates in lymphocyte differentiation. The extent to which these approaches will be capable of unraveling the relationship of various lymphocyte subpopulations is unknown, although the available evidence suggests that the principles thus far established may be central to the regulation of immune responses and consequently may be broadly applicable. In this review, the biology and biochemistry of interleukin-3 (IL-3) are discussed. Many of the properties of lL-3 are similar to lL-2 in that they promote differentiation and are required for growth by various lymphocyte lines. However, unlike lL-2, lL-3 appears to primarily influence a stage or stages of immature lymphocyte differentiation and, therefore, provides the means to dissect in vitro a completely unique aspect of lymphocyte differentiation.

Andrew J. Hapel

Papers

Molecular cloning of cDNA for murine interleukin-3.

Constitutive synthesis of interleukin-3 by leukaemia cell line WEHI-3B is due to retroviral insertion near the gene.

Constitutive production of a unique lymphokine (IL 3) by the WEHI-3 cell line.

Enhanced Mucosal Cytokine Production in Inflammatory Bowel Disease

Interleukin 3: Possible Roles in the Regulation of Lymphocyte Differentiation and Growth