Application of novel tissue microarrays to investigate expression of tryptase, chymase and KIT protein in placental mast cells

TMA-Mate: An open-source modular toolkit for constructing tissue microarrays of arbitrary layouts

Biomedical research and quality control procedures often demand a variety of microscopic analysis of numerous formalin-fixed and paraffin-embedded (FFPE) tissue samples from different individuals of both healthy and diseased regions of interest. Depending on the number of samples to be analyzed, conventional processing of each FFPE block separately can be laborious or impracticable. This effort can be drastically reduced by using tissue microarrays (TMAs). TMAs have a wide range of applications and can be considered as a high-throughput method to process up to hundreds of miniaturized tissue samples simultaneously on a single microscopy slide, in order to reduce labor, costs and sample consumption, and to increase results comparability. Several commercial and self-made solutions to fabricate TMAs with varying degrees of automation are available. However, these solutions may not be suitable for every situation, either due to high costs, high complexity, lack of precision or lack of flexibility, especially when diagnostically oriented pathology institutes or laboratories with constrained resources are considered. This article introduces the TMA-Mate, an open-source 3D printable modular toolkit for constructing high-density TMAs of arbitrary layouts, providing an affordable, lightweight, and accessible procedure to implement TMAs into existing histology processing pipelines. Step-by-step demonstrations for replicating the hardware and constructing TMAs are included.

Significance of mast cells in spermatogenesis, implantation, pregnancy, and abortion: Cross talk and molecular mechanisms

Both subsets of MCs including MC_TC (tryptase-positive, chymase-positive) and MC_T (tryptase-positive, chymase-negative) are present in the testis and epididymis. Increased number of MCs, higher levels of MC-released tryptase in testis and seminal plasma of males with fertility problems, and promoting sperm motility in individuals with oligozoospermia after using MC blockers provide evidence that MCs may play a role in male infertility/subfertility disturbances. MC-released tryptase and histamine contribute to the fibrosis and may disrupt spermatogenesis. MCs not only influence the process of spermatogenesis but also have effects on the function of other testis-residing cells. MC-derived histamine may influence the steroidogenesis of Leydig cells by acting through H1R and H2R receptors. Additionally, the interaction between MC-released ATP and P2X receptors expressed on the peritubular cells may induce the production of the pro-inflammatory mediators by peritubular cells. Further investigations showed that MCs may be involved in the pathology of female infertility during implantation, pregnancy, and abortion. In the uterus, MC_T subtype is abundant in myometrium and adjacent basal layer while MC_TC subtype is distributed in all layers. MCs in response to hormones mainly estradiol and progesterone become activated and release a wide range of mediators including histamine, VEGF, proteases, and metalloproteinases (MMPs) that have a role in different stages of pregnancy. An increasing influx of MCs to the cervix during the pregnancy occurs that helps to the physiologic cervical ripening. While MMPs degrade the extracellular matrix (ECM), VEGF modulates neovascularization and histamine influences the embryo implantation. MC-derived histamine may have a positive effect during implantation due to its participation in tissue remodeling. MC proteases including tryptase and chymase activate the precursors of MMP2 and MMP9 to mediate ECM degradation during the physiologic menstrual cycle. There is a line of evidence that MCs have a role in abortion by releasing TNF-α.

Temporal and spatial distribution of mast cells and steroidogenic enzymes in the human fetal adrenal

Mast cells are present in the human adult adrenal with a potential role in the regulation of aldosterone secretion in both normal cortex and adrenocortical adenomas. We have investigated the human developing adrenal gland for the presence of mast cells in parallel with steroidogenic enzymes profile and serotonin signaling pathway. RT-QPCR and immunohistochemical studies were performed on adrenals at 16-41 weeks of gestation (WG). Tryptase-immunopositive mast cells were found from 18 WG in the adrenal subcapsular layer, close to 3βHSD- and CYP11B2-immunoreactive cells, firstly detected at 18 and 24 WG, respectively. Tryptophan hydroxylase and serotonin receptor type 4 expression increased at 30 WG before the CYP11B2 expression surge. In addition, HDL and LDL cholesterol receptors were expressed in the subcapsular zone from 24 WG. Altogether, our findings suggest the implication of mast cells and serotonin in the establishment of the mineralocorticoid synthesizing pathway during fetal adrenal development.

CD117-positive cells of the heart: progenitor cells or mast cells?

Human cardiac stem/progenitor cells and their potential for repair of heart injury are a current hot topic of research. CD117 has been used frequently as a marker for identification of stem/progenitor cells in the heart. However, cardiac mast cells, which are also CD117(+), have not been excluded by credible means when selecting putative cardiac progenitors by using CD117 as a marker. We evaluated the relationship between CD117(+) cells and mast cells in the left ventricle of human hearts (n=5 patients, ages 1 week-75 years) with the well-established mast cell markers tryptase, toluidine blue, and thionine. A large number (85-100%) of CD117(+) cells in the human heart were specifically identified as mast cells. In addition, mast cells showed weak or moderate CD45 immunostaining signals. These results indicate that the majority of CD117(+) cells in the heart are mast cells and that these cells are distinctly positive for CD45, although staining was weak or moderate. These results strongly suggest that the newly reported CD117(+)/CD45(dim/moderate) putative cardiac progenitor cells are mast cells. The significance of this observation in stem cell research of the heart is discussed.

Regulation of natural-killer cell cytotoxicity and enhancement of complement factors in the spontaneously aborted mouse placenta

OBJECTIVE

To evaluate the cytotoxicity of uterine natural killer (NK) cells and identify major biological factors fluctuating in the spontaneously aborted placenta.

DESIGN

Spontaneously aborted placentae were examined by using histology, molecular biology, and DNA microarray analysis.

SETTING

Laboratories and animal center at a medical college.

ANIMAL(S)

C57BL/6 mice.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Up-regulation of the inhibitory system of uterine NK cells and enhancement of complement factors in aborted placenta.

RESULT(S)

In uteri on day 14 of pregnancy, 9.69% +/- 11.6% (+/-SD) implantation sites spontaneously aborted. Labyrinthine trophoblasts at abortion sites had nuclei that were positive for DNA fragment detection, as well as apoptotic morphology. Many uterine NK cells were present at abortion sites, but cytotoxic factors such as perforin, granzyme B, and Fas-Fas ligand were expressed at very low levels. In contrast, the expression level of Ly49 NK-cell receptors, which mediate an inhibitory signal for cytotoxicity, was enhanced at abortion sites. Deoxyribonucleic acid microarray analysis showed that adipsin, an activating enzyme for complement component C3, was strongly enhanced in aborted placenta, and positive reactions for adipsin and C3 were confirmed by immunohistochemistry.

CONCLUSION(S)

In the process of spontaneous abortion, the cytotoxicity of uterine NK cells is inhibited, and the innate immune system through adipsin and complement C3 appears to be influential.

Vascular remodeling and extracellular matrix breakdown in the uterine spiral arteries during pregnancy

During pregnancy, trophoblasts invade and transform the maternal spiral arteries that supply blood to the placenta. Recent work has revealed that this process occurs in several stages, and details of the molecular and cellular mechanisms are beginning to emerge, including changes that precede or accompany trophoblastic colonization of the vascular media. Disruption and eventual loss of smooth muscle cells and their associated extracellular matrix are central to physiological transformation. Advances in understanding will lead to the identification of the causative factors involved in failure of remodeling in pathological pregnancies and suggest novel diagnostic and therapeutic avenues.