Distinct impaired regulation of SOCS3 and long and short isoforms of the leptin receptor in visceral and subcutaneous fat of lean and obese women

Animal studies have illustrated the importance of the expression in adipose tissue of the leptin receptor (OB-R), and of SOCS3 an inhibitor of the leptin signaling pathway, in body weight regulation. The aim of the present study was to investigate in human adipose tissues of the same patients the OB-R isoforms and SOCS3 expression. Subcutaneous and omental adipose tissues were obtained from 6 lean and 18 morbidly obese women. The long isoform OB-Rb mRNA mediating leptin signaling, and SOCS3 mRNA are abundantly present in the subcutaneous fat of lean women, but are 90% and 70% decreased (P<0.0001) in obese women. In visceral fat from lean and obese women, both OB-Rb and SOCS3 mRNA are detected at very low levels. Subcutaneous/visceral ratios for OB-Ra the short OB-R isoform, OB-Rb, and SOCS3 mRNA abundance strongly correlate with the insulin sensitivity index, HOMA-% S, (r=0.49, P<0.0001, r=0.42, P=0.0002 and r=0.38, P=0.0002, respectively) in both lean and obese patients without type 2 diabetes. The near absence of OB-Rb mRNA and the similarly decreased SOCS3 expression in obese adipose tissue may reflect a defective leptin signaling pathway that could play a role in the impairment of insulin sensitivity associated with excess adiposity.     

A novel terminal differentiation model of human articular chondrocytes in three-dimensional cultures mimicking chondrocytic changes in osteoarthritis

This study establishes a cell culture model mimicking the terminal differentiation occurring in osteoarthritic chondrocytes. Normal articular chondrocytes obtained from human knees treated with 5-azacytidine (Aza-C) were harvested 3, 7 and 14 days after treatment. Phenotypic and genetic changes of articular chondrocytes were detected. The results show that mRNA expression of collagen type II, a marker for normal functional articular chondrocytes, was significantly decreased after Aza-C treatment in comparison to the control cultures, while those of collagen type X and ALP, markers for hypertrophic chondrocytes, were significantly increased. Cell size and apoptotic rate of articular chondrocytes showed significant increases compared to the control after 14 days of Aza-C treatment. Terminal differentiation is shown by this model of three-dimensional cultured human articular chondrocytes, which could apply to the studies of the cellular mechanisms of osteoarthritis.     

A Novel 2-dimensional Multiplex qPCR Assay for Single-Tube Detection of Nine Human Herpesviruses

Human herpesviruses are double-stranded DNA viruses that are classified into nine species. More than 90% of adults are ever infected with one or more herpesviruses. The symptoms of infection with different herpesviruses are diverse ranging from mild or asymptomatic infections to deadly diseases such as aggressive lymphomas and sarcomas. Timely and accurate detection of herpesvirus infection is critical for clinical management and treatment. In this study, we established a single-tube nonuple qPCR assay for detection of all nine herpesviruses using a 2-D multiplex qPCR method with a house-keeping gene as the internal control. The novel assay can detect and distinguish different herpesviruses with 30 to 300 copies per 25 μL single-tube reaction, and does not cross-react with 20 other human viruses, including DNA and RNA viruses. The robustness of the novel assay was evaluated using 170 clinical samples. The novel assay showed a high consistency (100%) with the single qPCR assay for HHVs detection. The features of simple, rapid, high sensitivity, specificity, and low cost make this assay a high potential to be widely used in clinical diagnosis and patient treatment.     

人粒细胞-巨噬细胞集落刺激因子研究进展

hGM-CSF是一种重要的具有免疫调节功能的糖蛋白,在造血调控和免疫调节方面发挥重要作用,具有重要的临床应用价值。总结近些年来各国对hGM-CSF的研究情况,首先对hGM-CSF的基因结构、蛋白分子结构、生物学活性等方面做了详细的介绍;接下来,又从基因转录水平和转录后水平两个方面对hGM-CSF的表达调控做了介绍;最后,对比了利用基因工程技术将hGM-CSF基因在不同生物中的表达情况,详细讲解了优缺点。     

The hippocampus and memory: a comparative and ethological perspective

During the past year, considerable progress has been made in our understanding of the wide-ranging functions of the hippocampus. Highlights include the development of new tasks with which to assess spatial/topographic memory in humans and monkeys, novel tests of relational memory in rats, and episodic-like memory tasks in birds. In addition, novel theories of hippocampal function have been developed that are notable for their applicability to both humans and animal models.     

The human serum albumin gene: structure of a unique locus

The entire gene for human serum albumin (HSA) has been isolated from a genomic DNA library, carried in the lambda Charon 4A vector. Six independent isolates have been found to hybridize to a cloned HSA cDNA probe, and all six clones share restriction site sequence homology in the overlapping portion of their DNA. These results seem to indicate that the albumin gene is single-copy, or unique, within the human haploid genome. Measuring from the "CAP" site to the "poly(A)" addition site, albumin gene comprises 16.5 kb of DNA.     

Photochemical internalization (PCI) of HER2-targeted toxins: Synergy is dependent on the treatment sequence

Background

Photochemical internalization (PCI) is a modality for cytosolic release of drugs trapped in endocytic vesicles. The method is based upon photosensitizers localized in the membranes of endocytic vesicles which create membrane rupture upon light exposure by generating reactive oxygen species (ROS), predominantly singlet oxygen (¹O₂).

Methods

The human epidermal growth factor receptor 2 (HER2)-targeted immunotoxin (IT), trastuzumab–saporin, was evaluated in combination with PCI using TPCS_2a (Amphinex®), a new photosensitizer approved for clinical use.

Results

PCI synergistically enhanced the cytotoxicity of trastuzumab–saporin on trastuzumab-resistant HER2⁺ Zr-75-1 cells. The PCI effect was only observed when the IT was administered prior to the photochemical treatment (“light after” strategy), while administration of a non-targeted drug may equally well be performed after light exposure. Mechanistic studies showed reduced ligand-induced HER2 phosphorylation and receptor-mediated endocytosis after TPCS_2a-PDT. Photochemical disruption of the cytoplasmic domain of HER2 was found to be induced by ¹O₂ generated both by photosensitizer located in the endocytic vesicles and in the outer leaflet of the plasma membrane.

Conclusions

Administration of the HER2-targeted toxin prior to light exposure is a prerequisite for successful PCI-mediated delivery of HER2-targeted toxins.

General significance

PCI of HER2-targeted toxins is demonstrated as a highly effective treatment modality which may overcome trastuzumab resistance. The mechanistic studies of the lack of PCI effect of the “light first” procedure is of outermost importance when designing a clinical PCI treatment protocol for delivery of HER2-targeted therapies.     

Using crowdsourcing to examine relations between delay and probability discounting

Although the extensive lines of research on delay and/or probability discounting have greatly expanded our understanding of human decision-making processes, the relation between these two phenomena remains unclear. For example, some studies have reported robust associations between delay and probability discounting, whereas others have failed to demonstrate a consistent relation between the two. The current study sought to clarify this relation by examining the relation between delay and probability discounting in a large sample of internet users (n = 904) using the Amazon Mechanical Turk (AMT) crowdsourcing service. Because AMT is a novel data collection platform, the findings were validated through the replication of a number of previously established relations (e.g., relations between delay discounting and cigarette smoking status). A small but highly significant positive correlation between delay and probability discounting rates was obtained, and principal component analysis suggested that two (rather than one) components were preferable to account for the variance in both delay and probability discounting. Taken together, these findings suggest that delay and probability discounting may be related, but are not manifestations of a single construct (e.g., impulsivity).     

The extinction context enables extinction performance after a change in context

One experiment with human participants determined the extent to which recovery of extinguished responding with a context switch was due to a failure to retrieve contextually controlled learning, or some other process such as participants learning that context changes signal reversals in the meaning of stimulus-outcome relationships. In a video game, participants learned to suppress mouse clicking in the presence of a stimulus that predicted an attack. Then, that stimulus underwent extinction in a different context (environment within the game). Following extinction, suppression was recovered and then extinguished again during testing in the conditioning context. In a final test, participants that were tested in the context where extinction first took place showed less of a recovery than those tested in a neutral context, but they showed a recovery of suppression nevertheless. A change in context tended to cause a change in the meaning of the stimulus, leading to recovery in both the neutral and extinction contexts. The extinction context attenuated that recovery, perhaps by enabling retrieval of the learning that took place in extinction. Recovery outside an extinction context is due to a failure of the context to enable the learning acquired during extinction, but only in part.