Phase separation of an actin nucleator by junctional microtubules regulates epithelial function

Liquid-liquid phase separation (LLPS) is involved in various dynamic biological phenomena. In epithelial cells, dynamic regulation of junctional actin filaments tethered to the apical junctional complex (AJC) is critical for maintaining internal homeostasis against external perturbations; however, the role of LLPS in this process remains unknown. Here, after identifying a multifunctional actin nucleator, cordon bleu (Cobl), as an AJC-enriched microtubule-associated protein, we conducted comprehensive in vitro and in vivo analyses. We found that apical microtubules promoted LLPS of Cobl at the AJC, and Cobl actin assembly activity increased upon LLPS. Thus, microtubules spatiotemporally regulated junctional actin assembly for epithelial morphogenesis and paracellular barriers. Collectively, these findings established that LLPS of the actin nucleator Cobl mediated dynamic microtubule-actin cross-talk in junctions, which fine-tuned the epithelial barrier

Intraspecific adaptation load: a mechanism for species coexistence

Evolutionary ecological theory suggests that selection arising from interactions with conspecifics, such as sexual and kin selection, may result in evolution of intraspecific conflicts and evolutionary ‘tragedy of the commons’. Here, we propose that such an evolution of conspecific conflicts may affect population dynamics in a way that enhances species coexistence. Empirical evidence and theoretical models suggest that more abundant species is more susceptible to invasion of ‘selfish’ individuals that increase their own reproductive success at the expense of population growth (intraspecific adaptation load). The density-dependent intraspecific adaptation load gives rise to a self-regulation mechanism at the population level, and stabilizes species coexistence at the community level by negative frequency-dependence

In vivo imaging of brain ischemia using an oxygen-dependent degradative fusion protein probe.

Within the ischemic penumbra, blood flow is sufficiently reduced that it results in hypoxia severe enough to arrest physiological function. Nevertheless, it has been shown that cells present within this region can be rescued and resuscitated by restoring perfusion and through other protective therapies. Thus, the early detection of the ischemic penumbra can be exploited to improve outcomes after focal ischemia. Hypoxia-inducible factor (HIF)-1 is a transcription factor induced by a reduction in molecular oxygen levels. Although the role of HIF-1 in the ischemic penumbra remains unknown, there is a strong correlation between areas with HIF-1 activity and the ischemic penumbra. We recently developed a near-infrared fluorescently labeled-fusion protein, POH-N, with an oxygen-dependent degradation property identical to the alpha subunit of HIF-1. Here, we conduct in vivo imaging of HIF-active regions using POH-N in ischemic brains after transient focal cerebral ischemia induced using the intraluminal middle cerebral artery occlusion technique in mice. The results demonstrate that POH-N enables the in vivo monitoring and ex vivo detection of HIF-1-active regions after ischemic brain injury and suggest its potential in imaging and drug delivery to HIF-1-active areas in ischemic brains

A Japanese concept of considerations for evaluation of dental materials for tooth bleaching

Recent advances in bleaching technology, such as bleaching ingredients, have accelerated the development of tooth whitening materials to change the color of natural teeth toward a lighter or whiter shade. Some bleaching materials are used for patients in combination with auxiliary medical devices to activate the bleaching materials by a light or heat source. Bleaching ingredients can be a poisonous and deleterious substance. Some bleaching materials are used in dental offices and the others at home. In clinical development of bleaching materials, appropriate evaluation of safety and efficacy is required according to the intended use. For appropriate and swift approval of the emerging bleaching materials, guideline on evaluation of dental whitening materials was discussed in a commissioned project by the Ministry of Health, Labour and Welfare of Japan for FY2021. Here, we summarize the current principles of the premarketing evaluation of the safety and efficacy

Serial pseudoprogression of metastatic malignant melanoma in a patient treated with nivolumab: a case report

Abstract Background Pseudoprogression refers to a specific pattern of response sometimes observed in malignant melanoma patients receiving treatment with immune-checkpoint inhibitors. Although cases with pseudoprogression documented once have been reported previously, there have been no case reports yet of pseudoprogression events documented twice during treatment. Case presentation A 55-year-old man underwent surgery for locally advanced esophageal malignant melanoma and received postoperative adjuvant interferon therapy. However, he presented with multiple liver and bone metastases at 6 months after the surgery, and was initiated on treatment with nivolumab 2 mg/kg every 3 weeks as the first-line treatment for recurrent disease. Follow-up computed tomography revealed that the liver metastases initially increased transiently in size, but eventually regressed. However, while the liver metastases continued to shrink, a new peritoneal nodule emerged, that also subsequently shrinked during the course of treatment with nivolumab. With only grade 1 pruritus, the patient continues to be on nivolumab treatment at 15 months after the induction therapy, with no progression observed after the second episode of pseudoprogression in the liver and peritoneal nodule. Conclusions We present the case of a patient with metastatic malignant melanoma who showed the unique response pattern of serial pseudoprogression during treatment with nivolumab. This case serves to highlight the fact that development of a new lesion may not always signify failure of disease control during treatment with nivolumab

Experimental design.

<p>(A) Cranial window in a C57/BL6 mouse. Experimental design of the closed cranial window. (B) Experimental design (upper panel). Representative two-dimensional images of cerebral blood flow measured by laser speckle perfusion imaging before MCAO (a), during MCAO (b), and after reperfusion (c) are shown in the lower panels. MCAO: middle cerebral artery occlusion.</p