Mechanistic insight of interleukin-9 induced osteoclastogenesis

Interleukin (IL)-9 is an emerging player in the pathogenesis of various chronic inflammatory diseases including bone disorders like rheumatoid arthritis (RA) and psoriatic arthritis. Recently, IL-9 was shown to enhance the osteoclast formation and their function in RA. However, the mechanisms by which IL-9 influences osteoclastogenesis are not known. Therefore, in this study we aimed to unravel the direct and indirect ways by which IL-9 can influence osteoclast formation. We used mouse bone marrow precursor cells for checking the effect of IL-9 on osteoclast differentiation and its function. Next, IL-9 induced signalling pathway were checked in the process of osteoclastogenesis. T cells play an important role in enhancing osteoclastogenesis in inflammatory conditions. We used splenic T cells to understand the impact of IL-9 on the functions of T effector (Teff) and regulatory T (Treg) cells. Furthermore, the effect of IL-9 mediated modulation of the T cell response on osteoclasts was checked using a coculture model of T cells with osteoclast precursors. We showed that IL-9 enhanced osteoclast formation and its function. We found that IL-9 activates STAT3, P38 MAPK, ERK1/2, NFκB and we hypothesize that it mediates the effect on osteoclastogenesis by accelerating mitochondrial biogenesis. Additionally, IL-9 was observed to facilitate the functions of pro-osteoclastogenic IL-17 producing T cells, but inhibits the function of anti-osteoclastogenic Treg cells. Our observations suggest that IL-9 can influence osteoclastogenesis directly by modulating the signalling cascade in the precursor cells; indirectly by enhancing IL-17 producing T cells and by reducing the functions of Treg cells.     

Early warning signals for Omicron outbreaks in China: A retrospective study

The Omicron variant has become the dominant COVID-19 variant worldwide due to its rapid and cryptic spread. Therefore, successful early warning is of great importance to be able to control epidemics in their early phase, before developing into large outbreaks. COVID-19-related Baidu search index, which reflects human behavior to a certain degree, was used to retrospectively detect the warning signs for Omicron variant outbreaks in China in 2022. The characteristics and effects of warning signs were analyzed in detail. We detected the presence of early warning signs (both high and low thresholds) and found that these occurred 4–7 days earlier than traditional epidemiological surveillance and >20 days earlier than the implementation of the local “lockdown” policy. Compared with the “high threshold” warning, the early warning effect of the “low threshold” is also vital because it indicates a negligence about epidemic prevention and control. However, there is obvious heterogeneity in the optimal threshold for detecting early warning signs and their distribution in different cities. Multi-source and multi-point early warning systems should be established via combining internet-based big data in the future to conduct effective and early real-time warning. This would create precious time for the early control of COVID-19 outbreaks.     

Inhibition of the epidermal growth factor receptor tyrosine kinase by PD153035 in human A431 tumors in athymic nude mice

Summary PD153035 is a potent (K_i=6 pm) and specific inhibitor of the epidermal growth factor (EOF) receptor tyrosine kinase that suppresses tyrosine phosphorylation of the EGF receptor in A431 cells at nanomolar concentrations in cell culture. We have examined the pharmacokinetics of this compound and its ability to rapidly suppress phosphorylation of the EGF receptor in A431 human epidermoid tumors grown as xenografts in immunodeficient nude mice. Following a single i.p. dose of 80 mg/kg, the drug levels in the plasma and tumor rose to 50 and 22 M within 15 minutes. While the plasma levels of PD153035 fell below 1 M by 3 hours, in the tumors it remained at micromolar concentrations for at least 12 hours. The tyrosine phosphorylation of the EGF receptor was rapidly suppressed by 80–90% in the tumors. However receptor phosphorylation returned to control levels after 3 hours despite the continued presence of the drug at concentrations which, based on previousin vitro results, were predicted to maintain inhibition. EGF-stimulated tyrosine kinase activity in tumor extracts was decreased and recovered in parallel with the effects of PD153035 on receptor phosphorylation though the activity had reached only about half of the control activity after three hours. These results demonstrate the potential for using small molecule inhibitors to inhibit the EGF receptor tyrosine kinasein vivo, though a fair evaluation of their potential anti-cancer activity will have to wait for solutions to problems with sustained delivery which may allow us to maintain suppression of EGF receptor phosphorylation.     

CARD In Situ Hybridization: Sights and Signals

During the last decade, several strategies have been developed to improve the detection sensitivity ofin situ hybridization (ISH) by amplification of either target nucleic acid sequences prior to ISH (e.g.,in situ PCR), or the detection signals after the hybridization procedures (signal amplification). Here we outline the principles of tyramide signal amplification using the catalyzed reporter deposition (CARD) technique, summarize applications as well as possible limitations of CARD ISH, and discuss some future directions ofin situ nucleic acid detection using this amplification strategy.     

Removal of cardiac beat artifact in oesophageal pressure measurement by frequency analysis

Oesophageal pressure (Pes) measurements are important in medical research and useful in clinical diagnosis. Measurements, however, are contaminated heavily by cardiac artifacts. The spectrum and waveform of the Pes signal is obtained from the oesophageal balloon. Adaptive finite impulse response (AFIR) filter and modified adaptive noise cancellation (MANC) methods are adopted to filter out cardiac beat interference. These results are compared. In the frequency domain, frequency variations and spectral overlap between the Pes components and cardiac beat signal components impact on the performance of the filter. From our experimental results on power strength, the fourth or higher harmonics did not have any significant effect on the filter performance. However, the second harmonics of these signals had a significant effect on the filtering result. Thus, in the design of AFIR filters, attention is needed to minimise these effects. In frequency analysis, these harmonics or overlapping frequencies do not affect MANC. MANC was the better method for eliminating cardiac beat artifact in Pes measurement. The dynamic compliance (Cdyn) was also used to evaluate the performance of MANC and AFIR. The standard deviation of Cdyn was less than 0.15 using MANC, compared with standard deviations as high as 0.57 for AFIR. We conclude that MANC performs better than AFIR.     

视频显示终端脉冲磁场对细胞间隙连接通讯功能的影响研究

目的：研究视频显示终端（ＶＤＴ）脉冲磁场对细胞间隙连接通讯功能的影响。方法：用１５．６ｋＨｚ、峰值强度为２００ μＴ的脉冲磁场（ＰＭＦ）和（或）十四酰基咐拜醇酯（ＴＰＡ：５ ｎｇ／ｍ ｌ）对培养的中国仓鼠肺成纤维细胞（ＣＨＬ）进行辐射２４ ｈ,采用离子电渗注射法观察荧光黄向与其接触的周围细胞的传递情况。结果：ＴＰＡ对细胞间隙连接通讯（ＧＪＩＣ）功能具有抑制作用,与空白对照组相比有显著差异（Ｐ＜ ０．０１）,单纯ＶＤＴ组对ＧＪＩＣ无抑制作用（Ｐ＞ ０．０５）,亦未见该脉冲磁场对ＴＰＡ的抑制作用有增强效应。结论：视频显示终端脉冲磁场（１５．６ ｋＨｚ）对细胞间隙连接通讯功能无直接和（或）协同ＴＰＡ的抑制作用     

锌激活体外培养大鼠成骨细胞肌醇磷脂信号转导系统

目的：　研究锌对体外培养大鼠成骨细胞肌醇磷脂信号转导系统的影响。方法：　从大鼠颅骨分离出成骨细胞,于 Ｄ Ｍ Ｅ Ｍ 培养基中进行传代培养。实验分为对照组、１０μｍｏｌ／ Ｌ、２５μｍｏｌ／ Ｌ 及５０μｍｏｌ／ Ｌ Ｚｎ２ ＋ 剂量组：分别测定了 Ｚｎ２ ＋ 对成骨细胞长期或短期作用后蛋白激酶 Ｃ（ Ｐ Ｋ Ｃ） 活性及三磷酸肌醇（ Ｉ Ｐ３） 含量的变化。根据被磷酸化多肽底物的量测定 Ｐ Ｋ Ｃ 活性,按照３ Ｈ ｍ ｙｏ 肌醇掺入及层析分离法测定 Ｉ Ｐ３ 含量。结果：　（１） 三个不同剂量的 Ｚｎ２ ＋ 作用于大鼠成骨细胞３ 天后, Ｉ Ｐ３ 含量及 Ｐ Ｋ Ｃ 活性均显著高于对照组;且随着 Ｚｎ２ ＋ 剂量的增加, Ｉ Ｐ３ 含量及 Ｐ Ｋ Ｃ 活性有相应增加的趋势;（２） 在短期实验中,２５μｍｏｌ／ Ｌ Ｚｎ２ ＋ 对成骨细胞的作用比较明显,仅作用１５ 分钟, Ｉ Ｐ３ 含量即明显提高,且在以后的各个作用时点均明显高于对照组,但时间效应曲线平坦;５０μｍ ｏｌ／ Ｌ Ｚｎ２ ＋ 组 Ｉ Ｐ３ 含量在各个时点略低于２５μｍｏｌ／ Ｌ Ｚｎ２ ＋组;１０μｍ ｏｌ／ Ｌ Ｚｎ２ ＋ 组略高于对照组。２５μｍｏｌ／ Ｌ Ｚｎ２ ＋ 、５０μｍ ｏｌ／ Ｌ Ｚｎ２ ＋ 组 Ｐ Ｋ