Acta Histochemica Et Cytochemica最新文献

The mouse hypoglossal nerve originates in the occipital motor nuclei at embryonic day (E)10.5 and projects a long distance, reaching the vicinity of the tongue primordia, the lateral lingual swellings, at E11.5. However, the details of how the hypoglossal nerve correctly projects to the primordia are poorly understood. To investigate the molecular basis of hypoglossal nerve elongation, we used a novel transcriptomic approach using the ROKU method. The ROKU algorithm identified 3825 genes specific for lateral lingual swellings at E11.5, of which 34 genes were predicted to be involved in axon guidance. Ingenuity Pathway Analysis-assisted enrichment revealed activation of the semaphorin signaling pathway during tongue development, and quantitative PCR showed that the expressions of Sema3d and Nrp1 in this pathway peaked at E11.5. Immunohistochemistry detected NRP1 in the hypoglossal nerve and SEMA3D as tiny granules in the extracellular space beneath the epithelium of the tongue primordia and in lateral and anterior regions of the mandibular arch. Fewer SEMA3D granules were localized around hypoglossal nerve axons and in the space where they elongated. In developing tongue primordia, tissue-specific regulation of SEMA3D might control the route of hypoglossal nerve projection via its repulsive effect on NRP1.

The effects of mechanical unloading after anterior cruciate ligament (ACL) reconstruction on bone and marrow adipose tissue (MAT) are unclear. We investigated weight bearing effects on bone and MAT after ACL reconstruction. Rats underwent unilateral knee ACL transection and reconstruction, followed by hindlimb unloading (non-weight bearing), no intervention (low-weight bearing, the hindlimb standing time ratio (STR; operated/contralateral) during treadmill locomotion ranging from 0.55 to 0.91), or sustained morphine administration (moderate-weight bearing, STR ranging from 0.80 to 0.95). Untreated rats were used as controls. At 7 or 14 days after surgery, changes in trabecular bone and MAT in the proximal tibial were assessed histologically. Histological assessments at 7 or 14 days after surgery showed that ACL reconstruction without post-operative intervention did not significantly change trabecular bone and MAT areas. Hindlimb unloading after ACL reconstruction induced MAT accumulation with adipocyte hyperplasia and hypertrophy within 14 days, but did not significantly affect trabecular bone area. Increased weight bearing through morphine administration did not affect trabecular bone and MAT parameters. Our results suggest that early weight bearing after ACL reconstruction is important in reducing MAT accumulation, and that reduction in weight bearing alone is not sufficient to induce bone loss early after ACL reconstruction.

[This corrects the article DOI: 10.1267/ahc.21-00081.].

The concentration of female-dominant steroid hormones, such as progesterone and estrogen, drops after birth in neonates. We have reported that neonatal estrogen treatment results in inflammation in the epididymis after puberty in male mice. Our recent study discovered that progesterone receptor was specifically expressed in efferent ducts just before birth in male mice. Therefore, this study aimed to reveal the impact of neonatal progesterone administration on the efferent ducts after puberty. Progesterone was subcutaneously administered to neonatal mice on their birthday in three groups: high-dose (200 mg/kg), low-dose (8 mg/kg), and control (cottonseed oil). Their testis and epididymis were collected at 12 weeks old. Semi-serial paraffin sections of these tissues were prepared and evaluated through PAS-hematoxylin staining. Efferent ducts were reconstructed into a three-dimensional structure, and their length and volume were analyzed. Spermatogenesis in the testis and epithelium of the tracts appeared normal, even in individuals administered with progesterone. There were no significant differences in the length and volume of the efferent ducts among the three groups. This study suggests that progesterone treatment in neonatal mice does not cause any structural changes in the male reproductive tracts at puberty, unlike the neonatal estrogen treatment.

Osimertinib is a third-generation, irreversible tyrosine kinase inhibitor (TKI) of epidermal growth factor receptor (EGFR) that selectively inhibits both EGFR-TKI-sensitizing and EGFR T790M resistance mutations and has shown efficacy in patients with non-small-cell lung cancer. In this study, we created osimertinib-specific antibodies and developed an immunohistochemistry (IHC) for locating the sites of osimertinib action. Moreover, we located osimertinib–protein conjugates in intestinal, dermal, and lung tissues of rats, thereby using our IHC to visualize the sites of the adverse effects of osimertinib, including diarrhea, skin disorder, and interstitial pneumonia. This report is the first to elucidate the localization of the sites of action of osimertinib in the rat intestine, skin, and lung and is expected to help clarify the mechanism of osimertinib-induced adverse effects.

Lymph nodes have contractile structures, but their distribution in a lymph node has been less considered in terms of facilitation of lymph flow. Axillary, inguinal, and mesenteric lymph nodes were collected from mice and human cadavers, and their sections were immuno­stained for alpha-smooth muscle actin (αSMA) and high molecular weight caldesmon (H-caldesmon). The αSMA-positive cells were localized in the capsule beneath the ceiling epithelium on the afferent side in both mice and humans. We found an additional layer of the αSMA-positive cells in the human lymph node, surrounding the inner layer perpendicularly. H-caldesmon was expressed only in these cells of the outer layer. In some human lymph nodes highly containing fat tissue in the medulla, the capsule disappeared on the efferent side, resulting in a disrupted sinusoidal lymph pathway. These findings suggest that human lymph nodes have additional smooth muscles in the outer region of the capsule to facilitate lymph flow. The αSMA-positive cells in the outer and inner layers of human lymph nodes probably have different functions in contraction. The presence of lipomatosis in a human lymph node will reduce its contribution to the lymph flow.

In the pathogenesis of Alzheimer’s disease (AD), highly neurotoxic amyloid-β (Aβ) oligomers appear early, they are thus considered to be deeply involved in the onset of Alzheimer’s disease. However, Aβ oligomer visualization is challenging in human tissues due to their multiple forms (e.g., low- and high-molecular-weight oligomers, including protofibrils) as well as their tendency to rapidly change forms and aggregate. In this review, we present two visualization approaches for Aβ oligomers in tissues: an immunohistochemical (using the monoclonal antibody TxCo1 against toxic Aβ oligomer conformers) and imaging mass spectrometry using the small chemical Shiga-Y51 that specifically binds Aβ oligomers. TxCo1 immunohistochemistry revealed Aβ oligomer distributions in postmortem human brains with AD. Using Shiga-Y51, imaging mass spectrometry revealed Aβ oligomer distributions in the brain of a transgenic mouse model for AD. These two methods would potentially contribute to elucidating the pathological mechanisms underlying AD.

Myogenic cell differentiation is modulated by multiple regulatory factors, such as myogenin, p21, and cyclin D3 during myogenesis in vitro. It is also recognized that myogenin and p21 play important roles in regulating muscle satellite cell (SC) differentiation during overload-induced muscle hypertrophy in vivo. However, the expression patterns and functional role of cyclin D3 in the progress of muscle hypertrophy remain unclear. Thus, the present study investigated cyclin D3 expression in skeletal muscles during early-stage functional overload. Plantaris muscles were exposed to functional overload due to ablation of the gastrocnemius and soleus muscles. As a result, cyclin D3 expression was detected in the nuclei of SCs but not in myonuclei on day 1 after surgery. Cyclin D3 expression, after functional overload, gradually increased, reaching a maximum on day 7 along with myogenin expression. Moreover, in response to the functional overload, cyclin D3 was expressed simultaneously with myogenin and p21 in SC nuclei. Therefore, the present study suggests that cyclin D3 with myogenin and p21 may interactively regulate SC differentiation during early-stage functional overload.

Insulinoma-associated protein 1 (INSM1) is a representative diagnostic marker of neuroendocrine neoplasms (NENs); however, it has not yet been used to diagnose pituitary neuroendocrine tumors (PitNETs), according to the 2022 World Health Organization (WHO) classification of pituitary tumors. This study aimed to examine the expression of INSM1 using immunohistochemistry, in the various cell lineages of PitNET classified by hormone secretion and transcription factor expression. INSM1 expression in PitNETs (different subtypes) and normal pituitary tissues was immunohistochemically assessed. The results were interpreted as scores of 0 (negative), 1 (focally positive), or 2 (frankly positive), depending on the proportion of cell staining. Twenty-eight of 35 PitNET cases (80%) showed INSM1 positivity in their nuclei. The staining in each histological subtype of PitNETs was as follows: somatotroph tumors, score 0 = 3/5, score 1 = 1/5, score 2 = 1/5; lactotroph tumors, score 0 = 2/5, score 1 = 1/5, score 2 = 2/5; thyrotroph tumors, score 2 = 5/5; corticotroph tumors: score 1 = 1/9, score 2 = 8/9; gonadotroph tumors, score 0 = 2/10, score 1 = 0/10, score 2 = 8/10; and unclassifiable tumor, score 1 = 1/1. INSM1 expression in most PitNETs was obtained, similar to that in the normal pituitary gland; thus, INSM1 may maintain the characteristics of anterior pituitary cells and pituitary tumors.

Current therapeutic modalities for pituitary neuroendocrine tumors (PitNETs) include medication, surgery, and radiotherapy. Some patients have tumors that are refractory to current modalities. Therefore, novel treatment options are needed for patients with intractable diseases. Consequently, we examined the pathological data of PitNETs to study medical therapies. We retrospectively studied 120 patients with histologically diagnosed PitNETs. We used the data for the histopathological examination of hormones, such as growth hormone (GH), prolactin (PRL), adrenocorticotropic hormone, thyroid stimulating hormone, luteinizing hormone, follicle-stimulating hormone, and α-subunit, together with the immunohistochemical studies of the phospho-mammalian target of rapamycin (mTOR), cytokeratin (CAM5.2), somatostatin receptor (SSTR) type 2 and 5, Pit-1 (POU1F1/GHF-1), steroidogenic factor-1 (SF-1), and Tpit. GH-, PRL-, and SSTR5-immunopositive PitNETs had significantly higher percentage of mTOR-positivity, compared with GH-, PRL-, and SSTR5-immunonegative Pit NETs. Our results show that activation of the AKT/phosphatidylinositol-3-kinase pathway, including mTOR activation, might be related the development of PitNETs, especially GH- and PRL-producing PitNETs. Thus, mTOR is a potential target for treating functional PitNETs.