Despite the increasing prevalence of Nonalcoholic steatohepatitis (NASH) worldwide, there is no effective treatment available for this disease. "Ballooned hepatocyte" is a characteristic finding in ...NASH and is correlated with disease prognosis, but their mechanisms of action are poorly understood; furthermore, neither animal nor in vitro models of NASH have been able to adequately represent ballooned hepatocytes. Herein, we engineered cell sheets to develop a new in vitro model of ballooned hepatocytes. Primary human hepatocytes (PHH) and Hepatic stellate cells (HSC) were co-cultured to produce cell sheets, which were cultured in glucose and lipid containing medium, following which histological and functional analyses were performed. Histological findings showed hepatocyte ballooning, accumulation of fat droplets, abnormal cytokeratin arrangement, and the presence of Mallory-Denk bodies and abnormal organelles. These findings are similar to those of ballooned hepatocytes in human NASH. Functional analysis showed elevated levels of TGFβ-1, SHH, and p62, but not TNF-α, IL-8. Exposure of PHH/HSC sheets to a glucolipotoxicity environment induces ballooned hepatocyte without inflammation. Moreover, fibrosis is an important mechanism underlying ballooned hepatocytes and could be the basis for the development of a new in vitro NASH model with ballooned hepatocytes.
Although recent vertebrate studies have revealed that different spinal networks are recruited in locomotor mode- and speed-dependent manners, it is unknown whether humans share similar neural ...mechanisms. Here, we tested whether speed- and mode-dependence in the recruitment of human locomotor networks exists or not by statistically extracting locomotor networks. From electromyographic activity during walking and running over a wide speed range, locomotor modules generating basic patterns of muscle activities were extracted using non-negative matrix factorization. The results showed that the number of modules changed depending on the modes and speeds. Different combinations of modules were extracted during walking and running, and at different speeds even during the same locomotor mode. These results strongly suggest that, in humans, different spinal locomotor networks are recruited while walking and running, and even in the same locomotor mode different networks are probably recruited at different speeds.
Modification of ongoing walking movement to fit changes in external environments requires accurate voluntary control. In cats, the motor and posterior parietal cortices have crucial roles for ...precisely adjusting limb trajectory during walking. In human walking, however, it remains unclear which cortical information contributes to voluntary gait modification. In this study, we investigated cortical activity changes associated with visually guided precision stepping using electroencephalography source analysis. Our results demonstrated frequency‐ and gait‐event‐dependent changes in the cortical power spectrum elicited by voluntary gait modification. The main differences between normal walking and precision stepping were as follows: (a) the alpha, beta or gamma power decrease during the swing phases in the sensorimotor, anterior cingulate and parieto‐occipital cortices, and (b) a power decrease in the theta, alpha and beta bands and increase in the gamma band throughout the gait cycle in the parieto‐occipital cortex. Based on the previous knowledge of brain functions, the former change was considered to be related to execution and planning of leg movement, while the latter change was considered to be related to multisensory integration and motor awareness. Therefore, our results suggest that the gait modification is achieved by higher cortical involvements associated with different sensorimotor‐related functions across multiple cortical regions including the sensorimotor, anterior cingulate and parieto‐occipital cortices. The results imply the critical importance of the cortical contribution to voluntary modification in human locomotion. Further, the observed cortical information related to voluntary gait modification would contribute to developing volitional control systems of brain–machine interfaces for walking rehabilitation.
We explored the cortical activity associated with gait modification using a precision stepping task and electroencephalography source analysis. We found the power decrease during the swing phases, which may be related to the execution and planning of leg movement, in the sensorimotor, anterior cingulate and parieto‐occipital cortices. In the parieto‐occipital cortex, we also found the power changes throughout the gait cycle, which may be related to multisensory integration and motor awareness.
Split-belt treadmill walking has been extensively utilized as a useful model to reveal the adaptability of human bipedal locomotion. While previous studies have clearly identified different types of ...locomotor adaptation, such as reactive and predictive adjustments, details of how the gait pattern would be adjusted are not fully understood. To gain further knowledge of the strategies underlying split-belt treadmill adaptation, we examined the three-dimensional ground reaction forces (GRF) and lower limb muscle activities during and after split-belt treadmill walking in 22 healthy subjects. The results demonstrated that the anterior component of the GRF (braking force) showed a clear pattern of adaptation and subsequent aftereffects. The muscle activity in the tibialis anterior muscle during the early stance phase was associated with the change of braking force. In contrast, the posterior component of GRF (propulsive force) showed a consistent increase/decrease in the fast/slow leg during the adaptation period and was not followed by subsequent aftereffects. The muscle activity in the gastrocnemius muscle during the stance phase gradually decreased during the adaptation phase and then showed a compensatory reaction during the washout phase. The results indicate that predictive feedforward control is required to set the optimal ankle stiffness in preparation for the impact at the heel contact and passive feedback control is used for the production of reflexively induced propulsive force at the end of the stance phase during split-belt treadmill adaptation. The present study provides information about the detailed mechanisms underlying split-belt adaptation and should be useful for the construction of specific rehabilitation protocols.
Two-dimensional sheet-like supramolecules have attracted much attention from the viewpoints of their potential application as functional (nano)materials due to unique physical and chemical ...properties. One of the supramolecular sheet-like nanostructures in nature is visible in the self-assemblies of bacteriochlorophyll-c-f pigments inside chlorosomes, which are major components in the antenna systems of photosynthetic green bacteria. Herein, we report artificial chlorosomal supramolecular nanosheets prepared by the self-assembly of a synthetic zinc 3
-methoxy-chlorophyll derivative having amide and urea groups in the substituent at the 17-position. The semi-synthetic zinc chlorophyll derivative kinetically formed dimeric species and transformed into more thermodynamically stable chlorosomal J-aggregates in the solid state. The kinetically and thermodynamically formed self-assemblies had particle-like and sheet-like supramolecular nanostructures, respectively. The resulting nanosheets of biomimetic chlorosomal J-aggregates had flat surfaces and well-ordered supramolecular structures. The artificial sheet-like nanomaterial mimicking chlorosomal bacteriochlorophyll-c-f J-aggregates was first constructed by the model molecule, and is potentially useful for various applications including artificial light-harvesting antennas and photosyntheses.
Walking with pulling force fields acting at the body center of mass (in the forward or backward directions) is compatible with inclined walking and is used in clinical practice for gait training. ...From the perspective of known differences in the motor strategies that underlie walking with the respective force fields, the present study elucidated whether the adaptation acquired by walking on a split-belt treadmill with either one of the force fields affects subsequent walking in a force field in the opposite directions. Walking with the force field induced an adaptive and de-adaptive behavior of the subjects, with the aspect evident in the braking and propulsive impulses of the ground reaction force (difference in the peak value between the left and right sides for each stride cycle) as parameters. In the parameters, the adaptation acquired during walking with a force field acting in one direction was transferred to that in the opposite direction only partially. Furthermore, the adaptation that occurred while walking in a force field in one direction was rarely washed out by subsequent walking in a force field in the opposite direction and thus was maintained independently of the other. These results demonstrated possible independence in the neural functional networks capable of controlling walking in each movement task with an opposing force field.
Various supramolecular nanotubes have recently been built up by lipids, peptides, and other organic molecules. Major light-harvesting (LH) antenna systems in a filamentous anoxygenic phototroph, ...Chloroflexus (Cfl.) aurantiacus, are called chlorosomes and contain photofunctional single-wall supramolecular nanotubes with approximately 5 nm in their diameter. Chlorosomal supramolecular nanotubes of Cfl. aurantiacus are constructed by a large amount of bacteriochlorophyll(BChl)-c molecules. Such a pigment self-assembles in a chlorosome without any assistance from the peptides, which is in sharp contrast to the other natural photosynthetic LH antennas. To mimic chlorosomal supramolecular nanotubes, synthetic models were prepared by the modification of naturally occurring chlorophyll(Chl)-a molecule. Metal complexes (magnesium, zinc, and cadmium) of the Chl derivative were synthesized as models of natural chlorosomal BChls. These metal Chl derivatives self-assembled in hydrophobic environments, and their supramolecules were analyzed by spectroscopic and microscopic techniques. Cryo-transmission electron microscopic images showed that the zinc and cadmium Chl derivatives could form single-wall supramolecular nanotubes and their outer and inner diameters were approximately 5 and 3 nm, respectively. Atomic force microscopic images suggested that the magnesium Chl derivative formed similar nanotubes to those of the corresponding zinc and cadmium complexes. Three chlorosomal single-wall supramolecular nanotubes of the metal Chl derivatives were prepared in the solid state and would be useful as photofunctional materials.
Pole walking (PW) has received attention not only as a whole-body exercise that can be adapted for elderly people with poor physical fitness but also as a possible intervention for the restoration of ...gait function in normal walking without the use of poles (i.e., conventional walking CW). However, the characteristics of PW, especially how and why PW training affects CW, remain unclear. The purpose of this study was to examine the characteristics of locomotor adaptation in PW from the perspective of kinematic variables. For this purpose, we compared the locomotor adaptation in PW and CW to that when walking on a split-belt treadmill in terms of spatial and temporal coordination. The result showed that adaptations to the split-belt treadmill in PW and CW were found only in interlimb parameters (step length and double support time ratios (fast/slow limb)), not in intralimb parameters (stride length and stance time ratios). In these interlimb parameters, the movement patterns acquired through split-belt locomotor adaptations (i.e., the aftereffects) were transferred between CW and PW regardless of whether the novel movement patterns were learned in CW or PW. The aftereffects of double support time and step length learned in CW were completely washed out by the subsequent execution in PW. On the other hand, the aftereffect of double support time learned in PW was not completely washed out by the subsequent execution in CW, whereas the aftereffect of step length learned in PW was completely washed out by the subsequent execution in CW. These results suggest that the neural mechanisms related to controlling interlimb parameters are shared between CW and PW, and it is possible that, in interlimb coordination, temporal coordination is preferentially stored in adaptation during PW.
Immunotherapy with immune‐checkpoint therapy has recently been used to treat oral squamous cell carcinomas (OSCCs). However, improvements in current immunotherapy are expected because response rates ...are limited. Transforming growth factor‐β (TGF‐β) creates an immunosuppressive tumor microenvironment (TME) by inducing the production of regulatory T‐cells (Tregs) and cancer‐associated fibroblasts and inhibiting the function of cytotoxic T‐lymphocytes (CTLs) and natural killer cells. TGF‐β may be an important target in the development of novel cancer immunotherapies. In this study, we investigated the suppressive effect of TGF‐β on CTL function in vitro using OSCC cell lines and their specific CTLs. Moreover, TGFB1 mRNA expression and T‐cell infiltration in 25 OSCC tissues were examined by in situ hybridization and multifluorescence immunohistochemistry. We found that TGF‐β suppressed the function of antigen‐specific CTLs in the priming and effector phases in vitro. Additionally, TGF‐β inhibitor effectively restored the CTL function, and TGFB1 mRNA was primarily expressed in the tumor invasive front. Interestingly, we found a significant negative correlation between TGFB1 mRNA expression and the CD8+ T‐cell/Treg ratio and between TGFB1 mRNA expression and the Ki‐67 expression in CD8+ T‐cells, indicating that TGF‐β also suppressed the function of CTLs in situ. Our findings suggest that the regulation of TGF‐β function restores the immunosuppressive TME to active status and is important for developing new immunotherapeutic strategies, such as a combination of immune‐checkpoint inhibitors and TGF‐β inhibitors, for OSCCs.
We found that, TGF‐β suppressed the function of antigen‐specific CTLs in the priming and effector phases in vitro. And, we found a significant negative correlation between TGFB1 mRNA expression and the CD8+ T‐cell/Treg ratio. Inhibition of TGF‐β restores the immunosuppressive TME to active status by a mechanism different from that of immune‐checkpoint inhibitors, suggesting that the combination of both may lead to a new therapeutic strategy for OSCCs.
Coordinated locomotor muscle activity is generated by the spinal central pattern generators (CPGs). Vertebrate studies have demonstrated the following two characteristics of the speed control ...mechanisms of the spinal CPGs: (i) rostral segment activation is indispensable for achieving high-speed locomotion; and (ii) specific combinations between spinal interneuronal modules and motoneuron (MN) pools are sequentially activated with increasing speed. Here, to investigate whether similar control mechanisms exist in humans, we examined spinal neural activity during varied-speed locomotion by mapping the distribution of MN activity in the spinal cord and extracting locomotor modules, which generate basic MN activation patterns. The MN activation patterns and the locomotor modules were analysed from multi-muscle electromyographic recordings. The reconstructed MN activity patterns were divided into the following three patterns depending on the speed of locomotion: slow walking, fast walking and running. During these three activation patterns, the proportion of the activity in rostral segments to that in caudal segments increased as locomotion speed increased. Additionally, the different MN activation patterns were generated by distinct combinations of locomotor modules. These results are consistent with the speed control mechanisms observed in vertebrates, suggesting phylogenetically conserved spinal mechanisms of neural control of locomotion.
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