Unfolded protein response is involved in the pathology of human congenital hypothyroid goiter and rat non-goitrous congenital hypothyroidism

Copyright: Copyright 2008 Elsevier B.V., All rights reserved.The unfolded protein response (UPR) is an intracellular signaling pathway that regulates the protein folding and processing capacity of the endoplasmic reticulum (ER). The UPR is induced by the pharmacological agents that perturb ER functions but is also activated upon excessive accumulation of the mutant secretory proteins that are unable to attain correct three-dimensional structure and are thus retained in the ER. Such defects in intracellular protein transport underlie the development of a number of phenotypically diverse inherited pathologies, termed endoplasmic reticulum storage diseases (ERSD). We have studied UPR development in two similar ERSDs, human congenital goiter caused by the C1264R and C1996S mutations in the thyroglobulin (Tg) gene and non-goitrous congenital hypothyroidism in rdw dwarf rats determined by the G2320R Tg mutation. In both cases, these mutations rendered Tg incapable of leaving the ER. A major ER chaperone immunoglobulin-binding protein (BiP), and a novel putative escort chaperone endoplasmic reticulum protein 29 KDa (ERp29) were found to be associated with Tg, which might be interpreted as the contribution of the quality control machinery to the previously shown retention of Tg in the ER. We have extended our earlier observations of ER chaperone induction with the identification of the additional ER (ERp29, ERp72, calreticulin, protein disulfide isomerase (PDI)), cytoplasmic (heat shock protein (HSP)70, HSP90) and mitochondrial (mtHSP70) upregulated chaperones and folding enzymes. Activation of the transcriptional arm of UPR, as judged by the appearance of the spliced (active) form of X-box binding protein (XBP1) and processed activating transcription factor 6 (ATF6) transcription factors was suggested to contribute to the overexpression of the ER chaperones. The processing of ATF6 was observed in both human and rat tissues with Tg mutations. Whereas, in human tissues, weak splicing of XBP1 mRNA was detected only in the C1264R mutant, all rat thyroids including wild-type contained significant amounts of the spliced form of XBP1 as opposed to human liver and rat brain tissues, implying the existence of a previously unknown tissue-specific regulation of XBP1 processing.publishersversionPeer reviewe

Lenalidomide Promotes the Development of TP53-Mutated Therapy-Related Myeloid Neoplasms

There is a growing body of evidence that therapy-related myeloid neoplasms (t-MNs) with driver gene mutations arise in the background of clonal hematopoiesis (CH) under the positive selective pressure of chemo- and radiation therapies. Uncovering the exposure relationships that provide selective advantage to specific CH mutations is critical to understanding the pathogenesis and etiology of t-MNs. In a systematic analysis of 416 patients with t-MN and detailed prior exposure history, we found that TP53 mutations were significantly associated with prior treatment with thalidomide analogs, specifically lenalidomide. We demonstrated experimentally that lenalidomide treatment provides a selective advantage to Trp53-mutant hematopoietic stem and progenitor cells (HSPCs) in vitro and in vivo, the effect of which was specific to Trp53-mutant HSPCs and was not observed in HSPCs with other CH mutations. Because of the differences in CK1α degradation, pomalidomide treatment did not provide an equivalent level of selective advantage to Trp53-mutant HSPCs, providing a biological rationale for its use in patients at high risk for t-MN. These findings highlight the role of lenalidomide treatment in promoting TP53-mutated t-MNs and offer a potential alternative strategy to mitigate the risk of t-MN development

GABAA Receptor-Mediated Acceleration of Aging-Associated Memory Decline in APP/PS1 Mice and Its Pharmacological Treatment by Picrotoxin

Advanced age and mutations in the genes encoding amyloid precursor protein (APP) and presenilin (PS1) are two serious risk factors for Alzheimer's disease (AD). Finding common pathogenic changes originating from these risks may lead to a new therapeutic strategy. We observed a decline in memory performance and reduction in hippocampal long-term potentiation (LTP) in both mature adult (9–15 months) transgenic APP/PS1 mice and old (19–25 months) non-transgenic (nonTg) mice. By contrast, in the presence of bicuculline, a GABAA receptor antagonist, LTP in adult APP/PS1 mice and old nonTg mice was larger than that in adult nonTg mice. The increased LTP levels in bicuculline-treated slices suggested that GABAA receptor-mediated inhibition in adult APP/PS1 and old nonTg mice was upregulated. Assuming that enhanced inhibition of LTP mediates memory decline in APP/PS1 mice, we rescued memory deficits in adult APP/PS1 mice by treating them with another GABAA receptor antagonist, picrotoxin (PTX), at a non-epileptic dose for 10 days. Among the saline vehicle-treated groups, substantially higher levels of synaptic proteins such as GABAA receptor α1 subunit, PSD95, and NR2B were observed in APP/PS1 mice than in nonTg control mice. This difference was insignificant among PTX-treated groups, suggesting that memory decline in APP/PS1 mice may result from changes in synaptic protein levels through homeostatic mechanisms. Several independent studies reported previously in aged rodents both an increased level of GABAA receptor α1 subunit and improvement of cognitive functions by long term GABAA receptor antagonist treatment. Therefore, reduced LTP linked to enhanced GABAA receptor-mediated inhibition may be triggered by aging and may be accelerated by familial AD-linked gene products like Aβ and mutant PS1, leading to cognitive decline that is pharmacologically treatable at least at this stage of disease progression in mice

Malignant inflammation in cutaneous T-cell lymphoma: a hostile takeover

Cutaneous T-cell lymphomas (CTCL) are characterized by the presence of chronically inflamed skin lesions containing malignant T cells. Early disease presents as limited skin patches or plaques and exhibits an indolent behavior. For many patients, the disease never progresses beyond this stage, but in approximately one third of patients, the disease becomes progressive, and the skin lesions start to expand and evolve. Eventually, overt tumors develop and the malignant T cells may disseminate to the blood, lymph nodes, bone marrow, and visceral organs, often with a fatal outcome. The transition from early indolent to progressive and advanced disease is accompanied by a significant shift in the nature of the tumor-associated inflammation. This shift does not appear to be an epiphenomenon but rather a critical step in disease progression. Emerging evidence supports that the malignant T cells take control of the inflammatory environment, suppressing cellular immunity and anti-tumor responses while promoting a chronic inflammatory milieu that fuels their own expansion. Here, we review the inflammatory changes associated with disease progression in CTCL and point to their wider relevance in other cancer contexts. We further define the term "malignant inflammation" as a pro-tumorigenic inflammatory environment orchestrated by the tumor cells and discuss some of the mechanisms driving the development of malignant inflammation in CTCL

Effect of silkworm peptide on inducting M1 type polarization and Th1 activation via TLR2‐induced MyD88‐dependent pathway

The aim of this study was to explore immune activity and molecular mechanism of silkworm peptide. The cell subsets induced by silkworm peptides were detected by flow cytometry. The IFN‐γ and IL‐4 levels in CD4+ cells were measured by ELISA. TLR2 mRNA expression in mouse CD4+ T cells was detected by qRT‐PCR. Western blot was used to detect the protein expression levels of MyD88 and p‐IκB. The growth rate of Lewis lung cancer xenografts in mice of the medium‐dose group was significantly reduced, and the tumor volume was significantly smaller than that of the control group on the 14th day. The relative vitality values of spleen lymphocytes in the medium‐dose and high‐dose groups were higher than the control group. The IFN‐γ levels in the medium‐dose and high‐dose groups were significantly higher than the control group. The levels of IL‐4 were no significant change among different groups. Compared with the control group, different doses of silkworm peptide groups could increase the levels of NO, IL‐6, IL‐12, and IL‐1β. Compared with the control group, the protein expression levels of MyD88 and p‐IκB in 10 μg/ml group and 20 μg/ml groups were significantly increased compared with the control group. Silkworm peptide could induce Th1 activation and M1 type polarization, which was dose‐dependent and was relative to the effect of silkworm peptide on inhibiting tumor growth. Silkworm peptide could directly induce M1 type polarization and Th1 activation via TLR2‐induced MyD88‐dependent pathway in vitro

Expression of glutamine synthetase and cell proliferation in human idiopathic epiretinal membrane

Background/aim: The mechanisms of the cellular origin and cell proliferation in the idiopathic epiretinal membrane (ERM) are unsolved. The aim of this study was to examine the expression of cell cycle related molecules and glutamine synthetase (GS), which is expressed in Müller cells and their processes, in ERM tissues. Methods: The ERMs were surgically removed using pars plana vitrectomy. Formalin fixed, paraffin embedded ERM tissues were analysed by immunohistochemistry with anti-cyclin D1, p27 (KIP1), proliferating cell nuclear antigen (PCNA), and GS antibodies. Results: The histopathological findings showed that all the ERMs consisted of oval or spindle mononuclear cells with thin collagen-like tissues. Immunoreactivity for GS was detected in collagen-like tissues of ERM, presenting a continuous, isodense pattern. GS immunopositive cells in all cases expressed PCNA in their nuclei. Nuclear immunoreactivity for cyclin D1 was noted in the ERM constituent cells, whereas p27 (KIP1) positive nuclei were not detected. Conclusion: Cyclin D1 and PCNA were expressed in the idiopathic ERM, which was mainly derived from Müller cells and extensions of their processes.http://www.bmj.co