Loss of p53 function promotes DNA damage-induced formation of nuclear actin filaments

Tumor suppressor p53 plays a central role in response to DNA damage. DNA-damaging agents modulate nuclear actin dynamics, influencing cell behaviors; however, whether p53 affects the formation of nuclear actin filaments remains unclear. In this study, we found that p53 depletion promoted the formation of nuclear actin filaments in response to DNA-damaging agents, such as doxorubicin (DOXO) and etoposide (VP16). Even though the genetic probes used for the detection of nuclear actin filaments exerted a promotive effect on actin polymerization, the detected formation of nuclear actin filaments was highly dependent on both p53 depletion and DNA damage. Whilst active p53 is known to promote caspase-1 expression, the overexpression of caspase-1 reduced DNA damage-induced formation of nuclear actin filaments in p53-depleted cells. In contrast, co-treatment with DOXO and the pan-caspase inhibitor Q-VD-OPh or the caspase-1 inhibitor Z-YVAD-FMK induced the formation of nuclear actin filament formation even in cells bearing wild-type p53. These results suggest that the p53-caspase-1 axis suppresses DNA damage-induced formation of nuclear actin filaments. In addition, we found that the expression of nLifeact-GFP, the filamentous-actin-binding peptide Lifeact fused with the nuclear localization signal (NLS) and GFP, modulated the structure of nuclear actin filaments to be phalloidin-stainable in p53-depleted cells treated with the DNA-damaging agent, altering the chromatin structure and reducing the transcriptional activity. The level of phosphorylated H2AX (γH2AX), a marker of DNA damage, in these cells also reduced upon nLifeact-GFP expression, whilst details of the functional relationship between the formation of nLifeact-GFP-decorated nuclear actin filaments and DNA repair remained to be elucidated. Considering that the loss of p53 is associated with cancer progression, the results of this study raise a possibility that the artificial reinforcement of nuclear actin filaments by nLifeact-GFP may enhance the cytotoxic effect of DNA-damaging agents in aggressive cancer cells through a reduction in gene transcription.

Statins Show Anti-Atherosclerotic Effects by Improving Endothelial Cell Function in a Kawasaki Disease-like Vasculitis Mouse Model

Kawasaki disease (KD) is an acute inflammatory syndrome of unknown etiology that is complicated by cardiovascular sequelae. Chronic inflammation (vasculitis) due to KD might cause vascular cellular senescence and vascular endothelial cell damage, and is a potential cause of atherosclerosis in young adults. This study examined the effect of KD and HMG-CoA inhibitors (statins) on vascular cellular senescence and vascular endothelial cells. Candida albicans water-soluble fraction (CAWS) was administered intraperitoneally to 5-week-old male apolipoprotein E-deficient (ApoE-) mice to induce KD-like vasculitis. The mice were then divided into three groups: control, CAWS, and CAWS+statin groups. Ten weeks after injection, the mice were sacrificed and whole aortic tissue specimens were collected. Endothelial nitric oxide synthase (eNOS) expression in the ascending aortic intima epithelium was evaluated using immunostaining. In addition, eNOS expression and levels of cellular senescence markers were measured in RNA and proteins extracted from whole aortic tissue. KD-like vasculitis impaired vascular endothelial cells that produce eNOS, which maintains vascular homeostasis, and promoted macrophage infiltration into the tissue. Statins also restored vascular endothelial cell function by promoting eNOS expression. Statins may be used to prevent secondary cardiovascular events during the chronic phase of KD.

2-Deoxy-d-glucose induces deglycosylation of proinflammatory cytokine receptors and strongly reduces immunological responses in mouse models of inflammation

Anti‐proinflammatory cytokine therapies against interleukin (IL)‐6, tumor necrosis factor (TNF)‐α, and IL‐1 are major advancements in treating inflammatory diseases, especially rheumatoid arthritis. Such therapies are mainly performed by injection of antibodies against cytokines or cytokine receptors. We initially found that the glycolytic inhibitor 2‐deoxy‐d‐glucose (2‐DG), a simple monosaccharide, attenuated cellular responses to IL‐6 by inhibiting N‐linked glycosylation of the IL‐6 receptor gp130. Aglycoforms of gp130 did not bind to IL‐6 or activate downstream intracellular signals that included Janus kinases. 2‐DG completely inhibited dextran sodium sulfate‐induced colitis, a mouse model for inflammatory bowel disease, and alleviated laminarin‐induced arthritis in the SKG mouse, an experimental model for human rheumatoid arthritis. These diseases have been shown to be partially dependent on IL‐6. We also found that 2‐DG inhibited signals for other proinflammatory cytokines such as TNF‐α, IL‐1β, and interferon ‐γ, and accordingly, prevented death by another inflammatory disease, lipopolysaccharide (LPS) shock. Furthermore, 2‐DG prevented LPS shock, a model for a cytokine storm, and LPS‐induced pulmonary inflammation, a model for acute respiratory distress syndrome of coronavirus disease 2019 (COVID‐19). These results suggest that targeted therapies that inhibit cytokine receptor glycosylation are effective for treatment of various inflammatory diseases.

Virus-infection in cochlear supporting cells induces audiosensory receptor hair cell death by TRAIL-induced necroptosis

Although sensorineural hearing loss (SHL) is relatively common, its cause has not been identified in most cases. Previous studies have suggested that viral infection is a major cause of SHL, especially sudden SHL, but the system that protects against pathogens in the inner ear, which is isolated by the blood-labyrinthine barrier, remains poorly understood. We recently showed that, as audiosensory receptor cells, cochlear hair cells (HCs) are protected by surrounding accessory supporting cells (SCs) and greater epithelial ridge (GER or Kölliker's organ) cells (GERCs) against viral infections. Here, we found that virus-infected SCs and GERCs induce HC death via production of the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). Notably, the HCs expressed the TRAIL death receptors (DR) DR4 and DR5, and virus-induced HC death was suppressed by TRAIL-neutralizing antibodies. TRAIL-induced HC death was not caused by apoptosis, and was inhibited by necroptosis inhibitors. Moreover, corticosteroids, the only effective drug for SHL, inhibited the virus-induced transformation of SCs and GERCs into macrophage-like cells and HC death, while macrophage depletion also inhibited virus-induced HC death. These results reveal a novel mechanism underlying virus-induced HC death in the cochlear sensory epithelium and suggest a possible target for preventing virus-induced SHL.

Cochlear supporting cells function as macrophage-like cells and protect audiosensory receptor hair cells from pathogens

To protect the audiosensory organ from tissue damage from the immune system, the inner ear is separated from the circulating immune system by the blood-labyrinth barrier, which was previously considered an immune-privileged site. Recent studies have shown that macrophages are distributed in the cochlea, especially in the spiral ligament, spiral ganglion, and stria vascularis; however, the direct pathogen defence mechanism used by audiosensory receptor hair cells (HCs) has remained obscure. Here, we show that HCs are protected from pathogens by surrounding accessory supporting cells (SCs) and greater epithelial ridge (GER or Kölliker’s organ) cells (GERCs). In isolated murine cochlear sensory epithelium, we established Theiler’s murine encephalomyelitis virus, which infected the SCs and GERCs, but very few HCs. The virus-infected SCs produced interferon (IFN)-α/β, and the viruses efficiently infected the HCs in the IFN-α/β receptor-null sensory epithelium. Interestingly, the virus-infected SCs and GERCs expressed macrophage marker proteins and were eliminated from the cell layer by cell detachment. Moreover, lipopolysaccharide induced phagocytosis of the SCs without cell detachment, and the SCs phagocytosed the bacteria. These results reveal that SCs function as macrophage-like cells, protect adjacent HCs from pathogens, and provide a novel anti-infection inner ear immune system.

Role of p53 in the Regulation of the Inflammatory Tumor Microenvironment and Tumor Suppression

p53 has functional roles in tumor suppression as a guardian of the genome, surveillant of oncogenic cell transformation, and as recently demonstrated, a regulator of intracellular metabolism. Accumulating evidence has shown that the tumor microenvironment, accompanied by inflammation and tissue remodeling, is important for cancer proliferation, metastasis, and maintenance of cancer stem cells (CSCs) that self-renew and generate the diverse cells comprising the tumor. Furthermore, p53 has been demonstrated to inhibit inflammatory responses, and functional loss of p53 causes excessive inflammatory reactions. Moreover, the generation and maintenance of CSCs are supported by the inflammatory tumor microenvironment. Considering that the functions of p53 inhibit reprogramming of somatic cells to stem cells, p53 may have a major role in the inflammatory microenvironment as a tumor suppressor. Here, we review our current understanding of the mechanisms underlying the roles of p53 in regulation of the inflammatory microenvironment, tumor microenvironment, and tumor suppression.

5-Aza-2'-deoxycytidine restores proapoptotic function of p53 in cancer cells resistant to p53-induced apoptosis

The expression of p53-target genes encoding the proapoptotic factor Noxa, but not PUMA, was not induced by p53 in HCT116 and SW480 cells, which show resistance to apoptosis in response to p53 overexpression. The lack of p53 inducibility of Noxa was restored by treatment with the DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5-aza-CdR). Furthermore, p53 induced apoptosis in HCT116 and SW480 cells treated with 5-aza-CdR. Moreover, the inhibition of Noxa expression by RNAi in 5-aza-CdR-treated HCT116 cells resulted in the partial inhibition of p53-induced apoptosis. These results suggest that epigenetic cancer therapy is possible for some cancers in combination with forced p53 activation.

YCu3Al2, an example of an AB5 structure type

Yttrium tricopper dialuminium, YCu(3)Al(2), is isostructural with hexagonal CaCu(5), in which each Cu atom at the 3g((1/2),0,(1/2)) position in space group P6/mmm (No. 191) is partially replaced by an Al atom. The hydrogen-uptake properties are usually enhanced in other AB(5) structures by aluminium substitution. YCu(5) does not show any hydrogen absorption, and the goal of the present work is to investigate whether aluminium substitution could expand the metal-atom lattice enough to provide better interstitial positions for hydrogen storage. However, no enthalpy change was observed up to 773 K under 3 MPa static H(2) pressure by differential thermal analysis (DTA) for the title compound. The compound does not show any significant hydrogen absorption/desorption in the pressure-composition isotherms (P-C-T diagrams) in the temperature range 298-673 K under 3.3 MPa H(2) pressure.

Transition from novelty to familiarity preference depending on recognition performance by 4-yr.-olds

Preference seems to depend exclusively on individual tastes; however, preferential behavior may be determined by memory, as past studies have shown that preferences for objects depended on whether objects had been previously experienced. Infants and young children prefer novel stimuli, while adults prefer familiar stimuli. To investigate the relationship between memory and preference directly, a preference task and a recognition task were administered to the same subjects. The subjects were 4-yr.-olds because Uehara observed a change in preference for novelty and familiarity in 4-yr.-olds, depending on their recognition performance. The results were similar to those of Uehara. The children who had lower scores in the recognition task preferred the novel stimuli in the preference task, and the children who had higher scores preferred the familiar. Developmental changes within children, from low scores on recognition coupled with novelty preference to high scores on recognition coupled with familiarity preference, were observed.

Differences in episodic memory between four- and five-year-olds: false information versus real experiences

It is assumed that personal episodes from any age less than about four years can rarely be recalled (infantile amnesia) because episodic memory is not well developed until this age. To investigate this, experiments were conducted with 30 4- and 30 5-yr.-olds. Experiments first examined whether the children could report parent-child games in a sports festival two days after the festival. The results indicated that 4-yr.-olds could not report the episodic contents of the games properly even though they reported the results of the ball matches as well as the 5-yr.-olds. Seven days after that report, the subject was told twice by the experimenter about realistic or unrealistic events as if these were their own experiences. The subject was again required to report the events seven days after receiving information. The results showed that 4-yr.-olds tended to mistake the information provided by the experimenter for their own real experiences. These results indicate that there may be a critical difference of episodic memory between 4- and 5-yr.-olds. Episodic memory was not well developed yet in 4-yr.-olds.

Differences in recognition and preference among four- and five-year-olds on a tactile learning and visual test

Infants' preferential looking at novel objects and adults' preference for the familiar indicate that preference may be influenced by whether the objects have been experienced previously. Infants and adults may have opposite preferential tendencies; however, infants' preference for a familiar object which they have experienced orally casts doubt on this as a developmental process. To examine both the influences of experienced modalities and age on the relationship between preference and memory, tactile-visual preference and memory tests were employed in 4- and 5-yr.-olds. The results indicated the dissociation of preference by recognition only in 4-yr.-olds: those who recognized the objects preferred the familiar and the 4-yr.-olds who could not recognize them preferred the novel. The 5-yr.-olds tended to prefer the familiar objects regardless of recognition. The results may suggest an age effect on the relationship between preference and recognition.

No transfer of visuomotor learning of button-pressing from right to left hands in right-handed four-year-olds

To assess the underlying mechanism of visuomotor learning in children and its relation to the cerebral lateralization, intermanual transfer of learning was examined on a button-press task. The main experiment examined transfer of learning from one hand to the other for 36 right-handed 4-yr.-olds, 19 5-yr.-olds, and 8 adults. The experiment consisted of three phases. In the first and second of three phases, the subject performed the task with the right [(or left) hand, then with the left (or right)]. All age groups exhibited transfer from the left to the right hands; however, the 4-yr.-olds showed no transfer from the right to the left, whereas the other age groups showed transfer from the right to the left as well as left to right. Results were discussed in relation to the underlying mechanism of learning and hemispheric organization, and a new interpretation was proposed.

Effects of zinc and copper content of formulas on growth and on the concentration of zinc and copper in serum and hair

We studied the effect of dietary zinc (Zn) and copper (Cu) on the levels of these elements in serum (at 1, 3, and 5 months of age) and in hair (at 5 months of age) of breast- and formula-fed infants. Three different formulas were used: (a) Commercially available standard infant formula containing 1.0 mg/L of Zn and 30 micrograms/L of Cu; (b) Zn supplemented formula, containing 3.2 mg/L of Zn and 30 micrograms/L of Cu; and (c) Zn- and Cu-supplemented formula, containing 3.2 mg/L of Zn and 400 micrograms/L of Cu. The median Zn content of breast milk was 4.8 mg/L at 1 week, 2.9 mg/L at 1 month, 1.1 mg/L at 3 months and 1.1 mg/L at 5 months. Breast milk Cu content was 510 micrograms/L at 1 week, 440 micrograms/L at 1 month, 270 micrograms/L at 3 months, and 200 micrograms/L at 5 months after delivery. All infants were healthy and full term, and weight and length velocities were similar in each of the four groups studied. Serum Zn levels were significantly higher both in the infants fed the Zn-supplemented formula and those fed the Zn-and-Cu-supplemented formula compared with the other two groups of infants at 3 and 5 months of age. Zn levels in hair were significantly elevated (invariably greater than 80 micrograms/g) only in infants fed Zn-supplemented formula.(ABSTRACT TRUNCATED AT 250 WORDS)

Four-hydroxyphenylpyruvic acid oxidase deficiency with normal fumarylacetoacetase: a new variant form of hereditary hypertyrosinemia

Enzymatic studies on the liver of an infant are described-a case of hypertyrosinemia without hepatic dysfunction. His parents were siblings and the mother had hypertyrosinemia. Excessive amounts of 4-hydroxyphenylpyruvic acid (pHPP), 4-hydroxyphenylacetic acid (pHPL), and 4-hydroxyphenylacetic acid (pHPA) were found to be excreted in the patient's urine as well as in the urine of the mother and the inhibitor of porphobilinogen synthetase was not found. Soluble tyrosine aminotransferase (s-TAT), separated from that of the mitochondrial form (m-TAT) by DE 52 column chromatography, was normal in the patient's liver, both quantitatively and qualitatively. The activities of fumarylacetoacetase in the patient's liver and in the peripheral leucocytes from the parents were normal. The activity of pHPP oxidase in the patient's liver was approximately 5% of the control and the enzyme had a high Km value for pHPP (controls: 0.06 +/- 0.01 mM, patient: 0.23 +/- 0.03 mM). From these results, the patient was thought to be different from previously described types of tyrosinemia and perhaps representative of a new variant form. This is the first report concerning 4-hydroxyphenylpyruvic acid oxidase deficiency alone. Mild metal retardation and mild hypertyrosinemia may be offered as typical clinical features of the disease.

Effect of low-content zinc and copper formula on infant nutrition

The zinc (Zn) content of commercially available formula milks in Japan is less than that of breast milk obtained during the first three months of lactation, but is similar to that at five months of lactation. The copper (Cu) content of the formula milks is much lower than that of breast milk obtained during the five months. These two trace elements were measured in serum (at birth, one, three, and five months of age), hair (at birth and at five months of age) and urine (at one, three and five months of age) of twenty-one breast fed and twenty formula fed full term infants. Despite the differences in Zn and Cu intakes, these parameters were similar in these two infant groups, except for urinary Zn at one and three months of age. These were significantly higher in breast fed infants (P less than 0.005 and P less than 0.05). Weight and length increments were not different in either infant group. It appeared that normal, full term infants tolerated low-content Zn and Cu formula milks well. This observation, however, is not at variance with the FAO/WHO recommendation for prevention of Zn and Cu deficiency.

Zinc and copper contents in breast milk of Japanese women

Longitudinal studies of zinc and copper contents of breast milk were performed in 65 Japanese mothers during their lactation period until 5 months postpartum. They experienced no problems during pregnancy and at delivery. All women had full term healthy infants. Forty-five were multiparous and 20 primiparous. The highest level of zinc content was found in the colostrum, and subsequently the levels declined (p less than 0.005), as lactation progressed. Copper content was stable during the first month of lactation, and then declined gradually (p less than 0.005). Both mineral levels in breast milk ranged with great variance among the subjects at any stages of lactation. Significantly lower zinc level (p less than 0.01) and higher copper level (p less than 0.005) were found in the serum of lactating women three months postpartum, when compared with non-lactating control women. Factors including lactation history, age of lactating women, serum levels and contents of zinc and copper in the hair did not affect the contents of these trace minerals in the breast milk.

Skin histidase activity and urine formiminoglutamic acid (FIGLU) in patients with histidinemia found by screening newborn infants

Skin histidase activities and urine formiminoglutamic acid (FIGLU) levels were measured in 20 patients with histidinemia, identified by Guthrie's screening method, and their family members as well as control subjects. There was a significant positive correlation between skin histidase activities and the amounts of urine FIGLU. Although the difference of skin histidase activity and the amount of urinary FIGLU was significant between any two of the three groups (i.e. controls, parents and patients; p less than 0.005), these levels ranged widely and a considerable number of the cases overlapped among groups. When a discriminant function was computed to obtain the minimum probability of misclassification between the groups using the above two parameters, a better segregation was observed. However, even though the number of misclassifications decreased, the overlapping cases were still present, especially between the parent and patient groups. It is concluded that either skin histidase activity, urine FIGLU, or both, can be used as genetic markers of the disease to a large but still limited extent.