Elevated receptor for activated C kinase 1 expression is involved in intracellular Ca2+ influx and potentially associated with compromised regulatory T cell function in patients with asthma

BACKGROUND

Regulatory T cells (T(regs)) are activated during anergy in response to T cell receptor (TCR) activation and functional immune suppression. Anergy of paediatric T(regs) is partially dependent on intracellular calcium mobility; following TCR activation, T(regs) do not exhibit increased intracellular Ca(2+) concentration ([Ca(2+) ](i)).

OBJECTIVE

We determined whether [Ca(2+) ](i) in adult T(regs) defined their anergy, if intracellular Ca(2+) movement was linked to regulatory functions, whether [Ca(2+)](i) was indicative of asthma pathology, and the potential molecular mechanism responsible for Ca(2+) movement in T(regs).

METHODS

T(regs) were purified by the magnetic bead method, and their regulatory functions were assessed by monitoring carboxyfluorescein succinimidyl ester-labelled responder T cell proliferation. The Ca(2+) response of Fura-2-labelled cells was measured using a video image analysis system. To analyse the functions of T(regs) at the molecular level, we generated Jurkat Tet-On(®) clones with doxycycline (Dox)-induced forkhead box P3 (FOXP3) protein expression.

RESULTS

CD4(+) CD25(+) CD127(-/low) T(regs) from participants without asthma did not elicit Ca(2+) influx in response to TCR activation, exhibited little proliferation and suppressed proliferation of CD4(+) CD25(-) T cells. In contrast, under similar conditions, T(regs) from patients with asthma exhibited increased [Ca(2+)](i) and robust proliferation with partial loss of regulatory functions. FOXP3 protein levels in Tet-On(®) clones were high after both 2- and 5-day Dox treatment; however, 5-day cells were comparable with T(regs) from patients with asthma, whereas 2-day cells were similar to T(regs) from participants without asthma. Increasing [Ca(2+)](i) induced a high level of receptor for activated C kinase 1 (RACK1) expression in 5-day cells.

CONCLUSIONS AND CLINICAL RELEVANCE

We confirmed that T(regs) in patients with asthma are functionally impaired and that the abnormal regulatory functions of these cells can be analysed by [Ca(2+)](i) following TCR engagement. Furthermore, the impaired functioning of T(regs) evident in patients with asthma may be due to a high level of RACK1.

Rehabilitation nutrition for sarcopenia with disability: a combination of both rehabilitation and nutrition care management

Malnutrition and sarcopenia often occur in rehabilitation settings. The prevalence of malnutrition and sarcopenia in older patients undergoing rehabilitation is 49-67 % and 40-46.5 %, respectively. Malnutrition and sarcopenia are associated with poorer rehabilitation outcome and physical function. Therefore, a combination of both rehabilitation and nutrition care management may improve outcome in disabled elderly with malnutrition and sarcopenia. The concept of rehabilitation nutrition as a combination of both rehabilitation and nutrition care management and the International Classification of Functioning, Disability and Health guidelines are used to evaluate nutrition status and to maximize functionality in the elderly and other people with disability. Assessment of the multifactorial causes of primary and secondary sarcopenia is important because rehabilitation nutrition for sarcopenia differs depending on its etiology. Treatment of age-related sarcopenia should include resistance training and dietary supplements of amino acids. Therapy for activity-related sarcopenia includes reduced bed rest time and early mobilization and physical activity. Treatment for disease-related sarcopenia requires therapies for advanced organ failure, inflammatory disease, malignancy, or endocrine disease, while therapy for nutrition-related sarcopenia involves appropriate nutrition management to increase muscle mass. Because primary and secondary sarcopenia often coexist in people with disability, the concept of rehabilitation nutrition is useful for their treatment. Stroke, hip fracture, and hospital-associated deconditioning are major causes of disability, and inpatients of rehabilitation facilities often have malnutrition and sarcopenia. We review the concept of rehabilitation nutrition, the rehabilitation nutrition options for stroke, hip fracture, hospital-associated deconditioning, sarcopenic dysphagia, and then evaluate the amount of research interest in rehabilitation nutrition.

Comprehensive approach to sarcopenia treatment

Sarcopenia is characterized by progressive and generalized loss of skeletal muscle mass and strength with a risk of adverse outcomes such as physical disability, poor quality of life, and death. Primary sarcopenia is considered to be age-related when no other cause is evident, other than ageing itself. Secondary sarcopenia should be considered when one or more other causes are evident, such as activity-, disease-, or nutrition-related sarcopenia. In this narrative review that focused on human studies, we summarize the pharmaceutical therapies (testosterone, dehydroepiandrosterone, estrogen, growth hormone, ghrelin, vitamin D, angiotensin converting enzyme inhibitor, and eicosapentaenoic acid) and nonpharmaceutical therapies (resistance training, protein and amino acid supplementation, and non-smoking) for counteracting primary sarcopenia. Testosterone and growth hormone improve muscle mass and muscle strength, but have several side effects. Although there are some intriguing pharmaceutical therapies to combat sarcopenia, resistance training combined with supplements containing amino acids are the most effective for preventing and treating age-related muscle wasting and weakness. The etiology of sarcopenia in the elderly is multi-factorial. Patients with disuse syndrome and deconditioning often complicate the diagnosis, of not only activity-related sarcopenia, but also age-, disease-, and nutrition-related sarcopenia. In these cases a comprehensive approach to sarcopenia treatment should include pharmaceutical therapies for age-related sarcopenia and comorbid chronic diseases, resistance training, early ambulation, nutrition management, protein and amino acid supplementation, and non-smoking. The effect of pharmaceutical therapies for sarcopenia can be enhanced by this comprehensive approach. Future research on pharmaceutical therapies for counteracting sarcopenia should consider non-pharmaceutical therapies and also the causes of sarcopenia.

[Transdisciplinary approach for sarcopenia. Sarcopenic Dysphagia]

Sarcopenic dysphagia is difficulty swallowing due to sarcopenia of generalized skeletal muscles and swallowing muscles. Presbyphagia refers to age-related changes in the swallowing mechanism in the elderly associated with a frailty in swallowing. Presbyphagia is different from dysphagia. The most common cause of dysphagia is stroke. However, sarcopenic dysphagia may be common in the elderly with sarcopenia and dysphagia. Frail elderly with aspiration pneumonia can simultaneously experience activity-, disease-, and nutrition-related sarcopenia of generalized skeletal muscles and swallowing muscles, resulting in the development of sarcopenic dysphagia. Consensus diagnostic criteria for sarcopenic dysphagia were proposed at the 19th Annual Meeting of the Japanese Society of Dysphagia Rehabilitation. The concept of rehabilitation nutrition as a combination of both rehabilitation and nutrition care management is useful for treatment of sarcopenic dysphagia. Therapy for sarcopenic dysphagia includes dysphagia rehabilitation, nutrition improvement and sarcopenia treatment. The core components of dysphagia rehabilitation are oral health care, rehabilitative techniques, and food modification. Nutrition improvement is important, because malnutrition contributes to the etiology of secondary sarcopenia and sarcopenic dysphagia. Assessment of the multi-factorial causes of primary and secondary sarcopenia is important because rehabilitation nutrition for sarcopenia differs depending on its etiology. Treatment of age-related sarcopenia should include resistance training and dietary supplements of amino acids. Therapy for activity-related sarcopenia includes reduced bed rest time and early mobilization and physical activity. Treatment for disease-related sarcopenia requires therapies for advanced organ failure, inflammatory disease, or malignancy, while therapy for nutrition-related sarcopenia involves appropriate nutrition management to increase muscle mass.

Combining mutations that modulate inter-subunit interactions and proteolytic inactivation enhance the stability of factor VIIIa

FVIIIa is labile due to the dissociation of A2 subunit. Previously, we introduced hydrophobic mutations at select A1/A2/A3 subunit interfaces yielding more stable FVIII(a) variants. Separately we showed that altering the sequence flanking the primary FXa cleavage site in FVIIIa (Arg336) yielded reduced rates of proteolytic inactivation of FVIIIa. In this study we prepared the FXa-cleavage resistant mutant (336(P4-P3')562) combined with mutations of Ala108Ile, Asp519Val/Glu665Val or Ala108Ile/Asp519Val/Glu665Val and examined the effects of these combinations relative to FVIII thermal stability, rates of FVIIIa decay and proteolytic inactivation of FVIIIa by FXa. Thermal decay rates for 336(P4-P3')562/Ala108Ile, 336(P4-P3')562/Asp519Val/Glu665Val, and 336(P4-P3')562/Ala108Ile/Asp519Val/Glu665Val variants were reduced by ~2- to 5-fold as compared with wild-type (WT) primarily reflecting the effects of the A domain interface mutations. FVIIIa decay rates for 336(P4-P3')562/Asp519Val/Glu665Val and 336(P4-P3')562/Ala108Ile/Asp519Val/Glu665Val variants were reduced by ~25 fold, indicating greater stability than the control Asp519Val/Glu665Val variant (~14-fold). Interestingly, 336(P4-P3')562/Asp519Val/Glu665Val and 336(P4-P3')562/Ala108Ile/Asp519Val/Glu665Val variants showed reduced FXa-inactivation rates compared with the 336(P4-P3')562 control (~4-fold), suggesting A2 subunit destabilisation is a component of proteolytic inactivation. Thrombin generation assays using the combination variants were similar to the Asp519Val/Glu665Val control. These results indicate that combining multiple gain-of-function FVIII mutations yields FVIII variants with increased stability relative to a single type of mutation.

Enhanced factor VIIIa stability of A2 domain interface variants results from an increased apparent affinity for the A2 subunit. Results from an increased apparent affinity for the A2 subunit

Factor (F)VIIIa, a heterotrimer comprised of A1, A2, and A3C1C2 subunits, is labile due to the tendency of the A2 subunit to dissociate from the A1/A3C1C2 dimer. As dissociation of the A2 subunit inactivates FVIIIa activity, retention of A2 defines FVIIIa stability and thus, FXase activity. Earlier results showed that replacing residues D519, E665, and E1984 at the A2 domain interface with Ala or Val reduced rates of FVIIIa decay, increasing FXa and thrombin generation. We now show the enhanced FVIIIa stability of these variants results from increases in inter-A2 subunit affinity. Using a FVIIIa reconstitution assay to monitor inter-subunit affinity by activity regeneration, the apparent Kd value for the interaction of wild-type (WT) A2 subunit with WT A1/A3C1C2 dimer (43 ± 2 nM) was significantly higher than values observed for the A2 point mutants D519A/V, E665A/V, and E1984A/V which ranged from ~5 to ~19 nM. Val was determined to be the optimal hydrophobic residue at position 665 (apparent Kd = 5.1 ± 0.7 nM) as substitutions with Ile or Leu at this position increased the apparent Kd value by ~3- and ~7-fold, respectively. Furthermore, the double mutant (D519V/E665V) showed an ~47-fold lower apparent Kd value (0.9 ± 0.6 nM) than WT. Thus these hydrophobic mutations at the A2 subunit interfaces result in high binding affinities for the A2 subunit and correlate well with previously observed reductions in rates in FVIIIa decay.

Isolation and characterization of halophilic lactic acid bacteria acting as a starter culture for sauce fermentation of the red alga Nori (Porphyra yezoensis)

AIMS

A screening test was conducted for environmental samples to isolate halophilic lactic acid bacteria (HLAB) that can act as a starter in a Nori (Porphyra yezoensis)-sauce culture.

METHOD AND RESULTS

After 9 months of incubation of enrichment cultures added with 25 kinds of environmental samples, growth of HLAB-like microorganisms was observed in six cultures salted at a 15% w/w level, including culture samples originally from mesopelagic water taken from 321 m-depth and from mountain snow taken at 2450 m-height. Ten strains were isolated and characterized as Tetragenococcus halophilus based on sequence analysis of the 16S rRNA gene. The isolates were inoculated into a newly prepared Nori-sauce culture and were confirmed to be able to act as a starter culture while three reference strains of T. halophilus obtained from a culture collection could not grow in the same culture.

CONCLUSIONS

Halophilic lactic acid bacteria strains that can make growth in a highly salted Nori-sauce culture were isolated from environmental samples for the first time. All the isolates were identified as T. halophilus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The isolated strains are expected to be utilized as a starter culture for manufacturing fermented seaweed-sauce, which will be the first fermented food products obtained from algae.

Oral administration of bovine lactoferrin attenuates ultraviolet B-induced skin photodamage in hairless mice

Lactoferrin (LF) is recognized as a host defensive glycoprotein, especially for newborn infants. The aim of this study was to investigate whether orally administered LF had protective activity against UV-induced skin damage in hairless mice. Transepidermal water loss and skin hydration were evaluated in nonirradiated mice, UVB-irradiated mice, and UVB-irradiated and LF-administered mice. Supplementation with LF (1,600 mg/kg per day) effectively suppressed the increase in transepidermal water loss, reduction in skin hydration, aberrant epidermal hyperplasia, and cell apoptosis induced by UV irradiation. Although no significant changes in superoxide dismutase-like activity or malondialdehyde levels were observed in the skin with both UV irradiation and LF administration, UV-stimulated IL-1β levels in the skin were significantly suppressed by the administration of LF. Oral supplementation with LF has the potential to reduce IL-1β levels and prevent UV-induced skin damage. Further studies are needed to elucidate the relationships between the antiinflammatory effects and skin protective function of LF.

Malnutrition is associated with poor rehabilitation outcome in elderly inpatients with hospital-associated deconditioning a prospective cohort study

OBJECTIVE

To investigate the association between nutritional status and rehabilitation outcome in elderly inpatients with hospital-associated deconditioning.

DESIGN

A prospective cohort study.

SUBJECTS/PATIENTS

One hundred sixty-nine consecutive elderly inpatients diagnosed with hospital-associated deconditioning.

METHODS

Nutritional status at referral was assessed by the Mini Nutritional Assessment Short Form at the University Medical Center. Body mass index, haemoglobin, albumin, total lymphocyte count, C-reactive protein, cause of malnutrition, and feeding route were also investigated. Primary outcome was Barthel Index score at discharge.

RESULTS

A total of 148 patients (87.6%) were malnourished, and 21 were at risk for malnutrition. There were no patients with normal nutritional status. Malnourished patients had a lower Barthel Index score at discharge than those at risk for malnutrition. Chronic disease-related malnutrition, oral intake, and parenteral nutrition were associated with the Barthel Index score at discharge. There were significant correlations between the Barthel Index score at discharge and nutritional score, albumin, and total lymphocyte count. In multiple regression analysis, Mini Nutritional Assessment Short Form, albumin, and chronic disease-related malnutrition were significantly associated with the Barthel Index score at discharge.

CONCLUSION

Most elderly inpatients with hospital-associated deconditioning are malnourished. Nutritional status, albumin, and chronic disease-related malnutrition are associated with poor rehabilitation outcome in hospital-associated deconditioning.

Identification of milk proteins enhancing the antimicrobial activity of lactoferrin and lactoferricin

Lactoferrin (LF) is known as an iron-binding antimicrobial protein present in exocrine secretions such as milk and releases the potent antimicrobial peptide lactoferricin (LFcin) by hydrolysis with pepsin. The antimicrobial activity of LF and LFcin has been studied well; however, their cooperative action with other milk proteins remains to be elucidated. In this study, we identified milk proteins enhancing the antimicrobial activity of bovine LF and LFcin against gram-negative bacteria, gram-positive bacteria, and fungi. As the target fraction, we isolated a minor milk protein fraction around 15 kDa, which was identified as bovine RNase 5 (angiogenin-1), RNase 4, and angiogenin-2 by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. As these proteins are collectively known as the RNase A family, we referred to the target protein fraction as milk RNase of 15 kDa (MR15). The number of colony-forming units of Escherichia coli and other pathogenic microorganisms with the addition of MR15 to LF (MR15:LF ratio=16:1,000) was dramatically lowered than that with LF alone. On the other hand, MR15 itself did not show any reductions in the number of colony-forming units at the concentrations tested. Similarly, the antimicrobial activities of LFcin against various microorganisms were significantly enhanced by the addition of MR15. These results suggest that LF and MR15 may be concomitantly acting antimicrobial agents in milk.