Jon D. Hennebold

Ovary-selective genes I: The generation and characterization of an ovary-selective complementary deoxyribonucleic acid library

The importance of several ovary-selective/specific genes, i.e. genes preferentially or exclusively expressed in the ovary, has been established. Indeed, null mutant female mice for the c-mos, growth and differentiation factor-9, alpha-inhibin, and zona pellucida-3 genes proved sterile. A loss of function mutation of the human FSH receptor gene established its critical role in ovarian function. These data support the hypothesis that genes expressed selectively or specifically in the ovary are probably essential for the normal functioning of this organ system. We have used the differential screening technique suppression subtractive hybridization to systematically isolate and clone genes that are expressed in an ovary-selective/specific manner. The resultant target complementary DNA (cDNA) library has been exhaustively screened to a point at which additional sequencing was increasingly unlikely (< or = 4%) to yield additional previously unencountered cDNAs. In toto, 844 clones were sequenced and analyzed for homology to known genes using the Basic Local Alignment Tool (BLAST). Of those, 342 were determined to be independent (nonredundant). One hundred and fifty-nine independent clones proved identical to previously characterized genes, whereas an additional 100 independent clones proved significantly homologous (but not identical) to previously characterized genes. Yet 83 other independent clones did not display significant homology to previously characterized genes now listed in the publicly accessible nonredundant databases. As such, these latter genes were deemed novel. Of these 83 novel genes, a total of 36 displayed ovary-specific/selective expression, as determined by probing mouse multitissue Northern blots with 32P-labeled/PCR-amplified cDNA inserts. Under these circumstances, the false positive rate was minimal, as only one novel clone was expressed at a higher level in nonovarian tissues relative to ovary. Of the 36 ovary-specific/ selective novel genes, 22 proved subject to hormonal regulation during a simulated estrous cycle. In this communication we focus on 2 such novel ovary-specific/hormonally-dependent genes, the full-length sequences of which were isolated using rapid amplification of 3-cDNA ends technology. Taken together, the present study accomplished systematic identification of those genes that are restricted in their expression to the ovary. These ovary-selective genes may have significant implications for the understanding of ovarian function in molecular terms and for the development of innovative strategies for the promotion of fertility or its control.

Does DHEAS Restore Immune Competence in Aged Animals through Its Capacity to Function as a Natural Modulator of Peroxisome Activities

Optimum function throughout life of an individual’s immune system is intimately dependent on the highly regulated production and biologic activities of a wellbalanced network of protein cytokines and growth factors. Collectively, these molecules are well established to be involved in the proliferation, differentiation, and survival of the various types of lymphoid cells that constitute the mammalian immune Their pleiotropic biologic activities, however, extend well beyond cell types associated with the immune system and include control over a diverse array of cellular and physiologic processes that occur in many distinct tissues and organ systems of the body.’,2 Age, stress, autoimmune diseases, and many infectious agents create conditions that can subvert normal host defenses through their capacity to detrimentally remodel the host’s highly coordinated cytokine network by effectively altering either the production of or the cellular responses to these protein molecules. Some of these conditions can actually elicit, without exogenous stimulation, a constitutive production of certain cytokine species by hyperactive lymphoid cells. This dysregulation in gene expression results in constant exposure of all cytokine responsive cells within the vicinity of the cytokine-producing cells to the modulatory activities of the abnormally produced and secreted molecules. Dysregulations in cytokine production, therefore, can lead to an altered state of cellular reactivity to exogenous agents or antigens and may result in a lowered capacity to elicit protective types of immune and inflammatory effector responses. Overexpression of some cytokines may also lead to increased autoantibody production which may ultimately proceed to the development of autoimmune disease. Steroids represent a class of small molecular weight bioactive molecules derived from cholesterol, many of which have long been known for their modulatory effects

Single-gene mutations resulting in reproductive dysfunction in women.

Fertility in women is regulated by a series of highly coordinated and synchronized interactions in the hypothalamic–pituitary–ovarian axis (Figure 1A). The central regulator of the axis is the group of neurons that secrete gonadotropin-releasing hormone (GnRH).1 Their cell bodies reside in the arcuate nucleus, and their exons terminate in the median eminence near the hypothalamic–pituitary portal vasculature. These neurons are unique in that they have an intrinsic firing frequency such that GnRH is secreted in pulses at 60-to-90-minute intervals into the portal vasculature to be conveyed to the anterior pituitary gland. There GnRH binds to specific cell-surface receptors on the .xa0.xa0.

Inhibition of skin 11β-hydroxysteroid dehydrogenase activity in vivo potentiates the anti-inflammatory actions of glucocorticoids

Abstract Synthetic forms of glucocorticoids (GCs) with high potency are widely used to treat a number of dermatological conditions having an inflammatory or autoimmune etiology. While GCs are generally effective in their ability to suppress inflammatory processes, their chronic use can lead to detrimental systemic side effects. In this report, we describe a method by which the localized antiinflammatory potential of the natural GC cortisol can be significantly augmented without increasing the risk of negative systemic effects. 11β-Hydroxysteroid dehydrogenase (11β-HSD) is a naturally occurring enzyme in the skin. 11β-HSD functionally converts biologically active 11-hydroxy GCs to their biologically inactive 11-keto metabolites, thereby limiting the ability of GCs to mediate antiinflammatory activities. By topically applying specific inhibitors of 11β-HSD in conjunction with low doses of GCs, the antiinflammatory properties of cortisol can be significantly potentiated. It was observed that the generation of the effector phase of contact hypersensitivity (CH) responses could be suppressed by this combined treatment under conditions where the 11β-HSD inhibitor alone, or cortisol alone were only minimally effective. Only the combined treatment was effective at inhibiting the progression of an ongoing CH response.

The generation and characterization of an ovary-selective cDNA library☆

We have utilized the differential screening technique suppression subtractive hybridization to systematically isolate and clone genes that are expressed in an ovary-selective/specific manner. In total, 844 clones were sequenced and analyzed for homology to known genes using the basic local alignment tool. One hundred and fifty nine independent clones proved identical to previously-characterized genes whereas an additional 100 independent clones proved significantly homologous (but not identical) to previously-characterized genes. Yet 83 other independent clones did not display significant homology to previously-characterized genes now listed in the publicly-accessible non-redundant databases. As such, these latter genes were deemed novel. In this communication we focus on two such novel ovary-specific/hormonally-dependent genes, the full-length sequences of which were isolated using RACE technology. These ovary-selective genes may have significant implications for the understanding of ovarian function in molecular terms and for the development of innovative strategies for the promotion of fertility or its control.

Microenvironmental control of glucocorticoid functions in immune regulation

Lipophilic hormones, including the steroids, thyroid hormones, retinoids, 1,25 dihydroxyvitamin D3, members of the prostaglandin J2 series, and leukotriene B4 represent a diverse group of molecules that can regulate gene expression through a common molecular mechanism. This diverse set of ligands traverse the plasma membrane and bind to ligand-specific intracellular receptors present within the cytosol, perinuclear space, or the nucleus of responsive cell types. Once activated by ligand binding, these intracellular receptors, which are all members of the steroid/nuclear receptor superfamily bind to specific sites on DNA and function as enhancers or repressors of gene transcription [1,2].