Age-related changes in scalp biophysical parameters: A comparative analysis of the 20s and 50s age groups.

BACKGROUND: Age-related changes in scalp parameters affect hair quality and scalp condition. However, detailed data on biophysical parameters of the scalp across age groups remain scarce. We aimed to investigate the differences in scalp parameters between individuals in their 20s and 50s and analyze their sex-specific variations. MATERIALS AND METHODS: Two hundred participants (160 women and 40 men) were equally divided into 20s and 50s age groups. Biophysical parameters of the scalp, including elasticity, pH, trans-epidermal water loss (TEWL), sebum production, desquamation, firmness, redness, and yellowness, were measured in the vertex, occipital, and temporal regions. Hair density and thickness were measured in the temporal region. The accumulation of advanced glycation end products (AGEs) in the skin was noninvasively measured in a subset of 60 women. RESULTS: Skin firmness and redness increased with age in women, whereas yellowness increased with age in both sexes. Sebum production and pH levels were significantly lower in the 50s age group than in the 20s age group, particularly in women. TEWL was lower in men in their 50s than in those in their 20s, particularly in the occipital region. A significant reduction in hair density was observed in the 50s age group in both sexes. AGE accumulation in the skin increased with age and was correlated with scalp skin yellowness. CONCLUSION: Age-related changes in scalp parameters have important implications for hair health and scalp condition. These findings emphasize the importance of considering age and sex when developing hair care strategies.

Early countermeasures to COVID-19 at long-term care facilities in Gwangju Metropolitan City, Republic of Korea

Objectives@#The coronavirus disease 2019 (COVID-19) pandemic has continued since its first detection in the Republic of Korea on January 20, 2020. This study describes the early countermeasures used to minimize the risk of COVID-19 outbreaks during cohort quarantine and compares the epidemiological characteristics of 2 outbreaks in long-term care facilities (LTCFs) in Gwangju Metropolitan City in summer 2020. @*Methods@#An epidemiological investigation was conducted via direct visits. We investigated epidemiological characteristics, including incidence, morbidity, and mortality rates, for all residents and staff members. Demographic characteristics were analyzed using a statistical program. Additionally, the method of managing infection in LTCFs is described. @*Results@#Residents and caregivers had high incidence rates in LTCF-A and LTCF-B, respectively. LTCF-B had a longer quarantine period than LTCF-A. The attack rate was 20.02% in LTCF-A and 27.9% in LTCF- B. The mortality rate was 2.3% (1/43) in LTCF-B, the only facility in which a COVID-19 death occurred. @*Conclusion@#Extensive management requires contact minimization, which involves testing all contacts to mitigate further transmission in the early stages of LTCF outbreaks. The findings of this study can help inform and prepare public health authorities for COVID-19 outbreaks, particularly for early control in vulnerable facilities.

Hospital mortality and prognostic factors in critically ill patients with acute kidney injury and cancer undergoing continuous renal replacement therapy

Whether continuous renal replacement therapy (CRRT) should be applied to critically ill patients with both acute kidney injury (AKI) and cancer remains controversial because of poor expected outcomes. The present study determined prognostic factors for all-cause in-hospital mortality in patients with AKI and cancer undergoing CRRT. Methods: We included 471 patients with AKI and cancer who underwent CRRT at the intensive care unit of a Korean tertiary hospital from 2013 to 2020, and classified them by malignancy type. The primary outcomes were 28-day all-cause mortality rate and prognostic factors for in-hospital mortality. The secondary outcome was renal replacement therapy (RRT) dependency at hospital discharge. Results: The 28-day mortality rates were 58.8% and 82% in the solid and hematologic malignancy groups, respectively. Body mass index (BMI), presence of oliguria, Sequential Organ Failure Assessment (SOFA) score, and albumin level were common predictors of 28-day mortality in the solid and hematologic malignancy groups. A high heart rate and the presence of severe acidosis were prognostic factors only in the solid malignancy group. Among the survivors, the proportion with RRT dependency was 25.0% and 33.3% in the solid and hematologic malignancy groups, respectively. Conclusion: The 28-day mortality rate of cancer patients with AKI undergoing CRRT was high in both the solid and hematologic malignancy groups. BMI, presence of oliguria, SOFA score, and albumin level were common predictors of 28-day mortality in the solid and hematologic malignancy groups, but a high heart rate and severe acidosis were prognostic factors only in the solid malignancy group.

Fasting and Non-Fasting Triglycerides in Patients With Acute Ischemic Stroke

Background@#Clinical implications of elevated fasting triglycerides (FTGs) and non-fasting triglycerides (NFTGs) in acute ischemic stroke (AIS) remain unknown. We aimed to elucidate the correlation and clinical significance of FTG and NFTG levels in AIS patients. @*Methods@#Using a multicenter prospective stroke registry, we identified AIS patients hospitalized within 24 hours of onset with available NFTG results. The primary outcome was a composite of stroke recurrence, myocardial infarction, and all-cause mortality up to one year. @*Results@#This study analyzed 2,176 patients. The prevalence of fasting and non-fasting hypertriglyceridemia was 11.5% and 24.6%, respectively. Multivariate analysis revealed that younger age, diabetes, higher body mass index and initial systolic blood pressure were independently associated with both fasting and non-fasting hypertriglyceridemia (all P < 0.05). Patients with higher quartiles of NFTG were more likely to be male, younger, eversmokers, diabetic, and have family histories of premature coronary heart disease and stroke (all P < 0.05). Similar tendencies were observed for FTG. The composite outcome was not associated with FTG or NFTG quartiles. @*Conclusion@#The fasting and non-fasting hypertriglyceridemia were prevalent in AIS patients and showed similar clinical characteristics and outcomes. High FTG and NFTG levels were not associated with occurrence of subsequent clinical events up to one year.

Identification of skin aging biomarkers correlated with the biomechanical properties.

BACKGROUND: Skin aging can be described as a combination of intrinsic and extrinsic aging. Various parameters for evaluating skin characteristics have been proposed. However, an accurate biomarker for skin aging and the relationship between biomarkers and biomechanical parameters of the skin is yet to be explored. MATERIALS AND METHODS: This study included 20 subjects by age. Skin aging was measured using non-invasive devices. Skin tissues were acquired through punch biopsy for immunohistochemistry and qRT-PCR of skin aging biomarkers, and analyzed correlation both, validated their use. RESULTS: Biomechanical properties of skin aging decreased with age. Among the biomarkers previously reported, we found that the expression of Moesin, TXNDC5, RhoGDI, and RSU1 decreased, while that of Vimentin and FABP5 increased with age. Pearson correlation showed that the expression levels of TXNDC5, RhoGDI, RSU1, and Vimentin were significantly correlated with the results of non-invasive measurements. In addition, the expression of TXNDC5, RhoGDI, and RSU1 increased, while that of Vimentin decreased, in skin explants upon treatment with one of the anti-aging compounds, retinoic acid. CONCLUSION: From this study, we identified practical molecular biomarkers of skin aging, TXNDC5, RhoGDI, RSU1, and Vimentin, which correlated with the skin biomechanical properties of skin aging.

2019 Tabletop Exercise for Laboratory Diagnosis and Analyses of Unknown Disease Outbreaks by the Korea Centers for Disease Control and Prevention

Objectives@#The Korea Centers for Disease Control and Prevention has published “A Guideline for Unknown Disease Outbreaks (UDO).” The aim of this report was to introduce tabletop exercises (TTX) to prepare for UDO in the future. @*Methods@#The UDO Laboratory Analyses Task Force in Korea Centers for Disease Control and Prevention in April 2018, assigned unknown diseases into 5 syndromes, designed an algorithm for diagnosis, and made a panel list for diagnosis by exclusion. Using the guidelines and laboratory analyses for UDO, TTX were introduced. @*Results@#Since September 9th , 2018, the UDO Laboratory Analyses Task Force has been preparing TTX based on a scenario of an outbreak caused by a novel coronavirus. In December 2019, through TTX, individual missions, epidemiological investigations, sample treatments, diagnosis by exclusions, and next generation sequencing analysis were discussed, and a novel coronavirus was identified as the causal pathogen. @*Conclusion@#Guideline and laboratory analyses for UDO successfully applied in TTX. Conclusions drawn from TTX could be applied effectively in the analyses for the initial response to COVID-19, an ongoing epidemic of 2019 - 2020. Therefore, TTX should continuously be conducted for the response and preparation against UDO.

The relationship between precarious employment and subjective well-being in Korean wage workers through the Cantril ladder Scale

Background@#The global labor market is moving towards increasing job instability. Relatively few studies have examined the relationship between precarious employment and subjective well-being using quantitative scales. We evaluated the association between wage workers' employment status and their subjective well-being through the Cantril ladder scale using Korean Welfare Panel Survey data (KOWEPS). @*Methods@#This study used KOWEPS data. A total of 4,423 wage workers were divided into permanently employed workers, temporarily employed workers and daily employed workers.The relationship between precarious employment and subjective well-being was analyzed by multiple linear regression adjusted for potential confounding factors. @*Results@#The more unstable the employment status, the lower the subjective well-being, which can be expressed by the Cantril ladder scale. The mean score of both temporarily employed and daily employed workers were statistically significantly lower (B = −0.454, p < 0.001; B = −0.994, p < 0.001, respectively) than permanently employed workers. This appeared to be the same when occupational and sociodemographic factors were adjusted (B = −0.153, p = 0.002 for temporarily employed, B = −0.610, p < 0.001 for daily employed). @*Conclusions@#The more unstable the employment status, the lower the subjective well-being score according to the Cantril ladder scale.

Longitudinal associations between occupational stress and depressive symptoms

Background@#Most of the studies that have examined the association between the sub-factors of occupational stress and depressive symptoms have used cross-sectional data. However, our study has longitudinally measured the occupational stress and depressive symptoms of Korean workers of a semiconductor manufacturing company across six years to intending to investigate the associations between the sub-factors of occupational stress and depressive symptoms using longitudinal data. @*Methods@#Data collected from the workers of a semiconductor manufacturing company.Out of 1,013 recruited workers, 405 (40.0%) completed the survey questionnaires at 3 and 6-year follow-ups. Occupational stress was measured using a shorter version of the Korean Occupational Stress Scale (KOSS), whereas depressive symptoms were assessed using the Korean version of the Center for Epidemiological Studies-Depressive Symptoms Scale (CES-D). The data of male and female participants independently analyzed. Longitudinal associations were analyzed using panel data analysis with fixed effects. @*Results@#In panel data analysis with fixed effects, job insecurity (B = 0.048, p-value = 0.004) was associated with depressive symptoms among male workers. In female workers, inadequate social support (B = 0.080, p-value < 0.001), job insecurity (B = 0.039, p-value = 0.004), lack of reward (B = 0.059, p-value = 0.004) and discomfort in occupational climate (B = 0.074, p-value < 0.001) were associated with depressive symptoms among female workers. @*Conclusions@#Temporal changes in the sub-factors of occupational stress were associated with changes in depressive symptoms within the same period. There was a gender difference in occupational stress sub-factors related to depressive symptoms.

Do Face Masks become Worthless after Only One Use in the COVID-19 Pandemic? / 감염과화학요법

Background@#Due to coronavirus disease 2019 (COVID-19), world-wide face mask use is increasing exponentially. These face masks are difficult to recycle, and their accumulation contributes to enormous environmental threats. In this study, we hypothesize that the face mask can be reused as long as it retains its original structure, which will slow the environmental impacts. @*Materials and Methods@#We selected common disposable surgical masks for this study and classified test conditions based on wear time and reuse method. After wearing the mask for 10 hours, we let it dry naturally in the shade for 14 hours. The specimens were measured by scanning electron microscope and capillary flow porometer. @*Results@#The pore structure of the mask did not change when worn 4 times for 10 hours each time, and there was no significant pore structure change when impregnated with ethyl alcohol (purity 95%), treated with UV or steam, or run through a washing machine. @*Conclusion@#The pore structure of the surgical mask was not changed significantly after 40 hours of use. Surgical mask pore structure did not change significantly after treatment with ethyl alcohol, UV light, steam, or a washing machine.

Recent Insights into Cellular Crosstalk in Respiratory and Gastrointestinal Mucosal Immune Systems

The human body is continuously threatened by pathogens, and the immune system must maintain a balance between fighting infection and becoming over-activated. Mucosal surfaces cover several anatomically diverse organs throughout the body, such as the respiratory and gastrointestinal tracts, and are directly exposed to the external environment.Various pathogens invade the body through mucosal surfaces, making the mucosa the frontline of immune defense. The immune systems of various mucosal tissues display distinctive features that reflect the tissues' anatomical and functional characteristics. This review discusses the cellular components that constitute the respiratory and gastrointestinal tracts; in particular, it highlights the complex interactions between epithelial and immune cells to induce Ag-specific immune responses in the lung and gut. This information on mucosal immunity may facilitate understanding of the defense mechanisms against infectious agents that invade mucosal surfaces, such as severe acute respiratory syndrome coronavirus 2, and provide insight into effective vaccine development.

The relationship between precarious employment and subjective well-being in Korean wage workers through the Cantril ladder Scale

Background@#The global labor market is moving towards increasing job instability. Relatively few studies have examined the relationship between precarious employment and subjective well-being using quantitative scales. We evaluated the association between wage workers' employment status and their subjective well-being through the Cantril ladder scale using Korean Welfare Panel Survey data (KOWEPS). @*Methods@#This study used KOWEPS data. A total of 4,423 wage workers were divided into permanently employed workers, temporarily employed workers and daily employed workers.The relationship between precarious employment and subjective well-being was analyzed by multiple linear regression adjusted for potential confounding factors. @*Results@#The more unstable the employment status, the lower the subjective well-being, which can be expressed by the Cantril ladder scale. The mean score of both temporarily employed and daily employed workers were statistically significantly lower (B = −0.454, p < 0.001; B = −0.994, p < 0.001, respectively) than permanently employed workers. This appeared to be the same when occupational and sociodemographic factors were adjusted (B = −0.153, p = 0.002 for temporarily employed, B = −0.610, p < 0.001 for daily employed). @*Conclusions@#The more unstable the employment status, the lower the subjective well-being score according to the Cantril ladder scale.

Longitudinal associations between occupational stress and depressive symptoms

Background@#Most of the studies that have examined the association between the sub-factors of occupational stress and depressive symptoms have used cross-sectional data. However, our study has longitudinally measured the occupational stress and depressive symptoms of Korean workers of a semiconductor manufacturing company across six years to intending to investigate the associations between the sub-factors of occupational stress and depressive symptoms using longitudinal data. @*Methods@#Data collected from the workers of a semiconductor manufacturing company.Out of 1,013 recruited workers, 405 (40.0%) completed the survey questionnaires at 3 and 6-year follow-ups. Occupational stress was measured using a shorter version of the Korean Occupational Stress Scale (KOSS), whereas depressive symptoms were assessed using the Korean version of the Center for Epidemiological Studies-Depressive Symptoms Scale (CES-D). The data of male and female participants independently analyzed. Longitudinal associations were analyzed using panel data analysis with fixed effects. @*Results@#In panel data analysis with fixed effects, job insecurity (B = 0.048, p-value = 0.004) was associated with depressive symptoms among male workers. In female workers, inadequate social support (B = 0.080, p-value < 0.001), job insecurity (B = 0.039, p-value = 0.004), lack of reward (B = 0.059, p-value = 0.004) and discomfort in occupational climate (B = 0.074, p-value < 0.001) were associated with depressive symptoms among female workers. @*Conclusions@#Temporal changes in the sub-factors of occupational stress were associated with changes in depressive symptoms within the same period. There was a gender difference in occupational stress sub-factors related to depressive symptoms.

Do Face Masks become Worthless after Only One Use in the COVID-19 Pandemic? / 감염과화학요법

Background@#Due to coronavirus disease 2019 (COVID-19), world-wide face mask use is increasing exponentially. These face masks are difficult to recycle, and their accumulation contributes to enormous environmental threats. In this study, we hypothesize that the face mask can be reused as long as it retains its original structure, which will slow the environmental impacts. @*Materials and Methods@#We selected common disposable surgical masks for this study and classified test conditions based on wear time and reuse method. After wearing the mask for 10 hours, we let it dry naturally in the shade for 14 hours. The specimens were measured by scanning electron microscope and capillary flow porometer. @*Results@#The pore structure of the mask did not change when worn 4 times for 10 hours each time, and there was no significant pore structure change when impregnated with ethyl alcohol (purity 95%), treated with UV or steam, or run through a washing machine. @*Conclusion@#The pore structure of the surgical mask was not changed significantly after 40 hours of use. Surgical mask pore structure did not change significantly after treatment with ethyl alcohol, UV light, steam, or a washing machine.

Recent Insights into Cellular Crosstalk in Respiratory and Gastrointestinal Mucosal Immune Systems

The human body is continuously threatened by pathogens, and the immune system must maintain a balance between fighting infection and becoming over-activated. Mucosal surfaces cover several anatomically diverse organs throughout the body, such as the respiratory and gastrointestinal tracts, and are directly exposed to the external environment.Various pathogens invade the body through mucosal surfaces, making the mucosa the frontline of immune defense. The immune systems of various mucosal tissues display distinctive features that reflect the tissues' anatomical and functional characteristics. This review discusses the cellular components that constitute the respiratory and gastrointestinal tracts; in particular, it highlights the complex interactions between epithelial and immune cells to induce Ag-specific immune responses in the lung and gut. This information on mucosal immunity may facilitate understanding of the defense mechanisms against infectious agents that invade mucosal surfaces, such as severe acute respiratory syndrome coronavirus 2, and provide insight into effective vaccine development.

Relationship between occupational sunlight exposure and the incidence of renal cancer

BACKGROUND: The risk factors for renal cancer include smoking, obesity, hypertension, and exposure to trichloroethylene. Recent studies have shown that low sunlight exposure increases the risk of developing a range of cancers, including renal cancer. Given that most of the daytime is spent at work, a lack of occupational sunlight exposure can be a risk factor for renal cancer. Therefore, this study examined the relationship between occupational sunlight exposure and the incidence of renal cancer. METHODS: This was a university hospital-based case-control study on renal cancer. Of the 706 newly diagnosed patients with renal cell carcinoma (RCC), 633 cases were selected; 73 who had no occupational history were excluded. In addition, 633 controls were selected from the general population after 1:1 matching with respect to sex, age (within 5 years), and residential area (constituency-level). Information on sunlight exposure by the occupational group was referred to data from France. To estimate the association between occupational sunlight exposure and the RCC risk, the odds ratios (ORs) were calculated using conditional logistic regression analysis. RESULTS: Sunlight exposure was divided into quartiles and the risk of RCC was analyzed. The adjusted OR of RCC (OR: 0.664, 95% confidence interval: 0.449–0.983) was significantly lower for the Q4 group than Q1 group but the Q2 and Q3 groups did not show significant results. The risk of RCC tended to decrease with increasing exposure to sunlight (p for trend < 0.028). CONCLUSIONS: Higher occupational sunlight exposure reduces the risk of RCC.

Influence of Awareness and Perceived Ease in Using Parental Leave on Job Satisfaction of Nurses in a Public Hospital / 간호행정학회지

PURPOSE: The aim of this study was to identify whether awareness and perceived ease in using parental leave influence job satisfaction of nurses in a public hospital. METHODS: The participants were 425 nurses working in a public hospital. A questionnaire was used to collect data from October 12 to October 25, 2016. The influence of the factors on job satisfaction of nurses was analyzed by multiple hierarchical regression. RESULTS: Nurses taking leave accounted for 46.8% (75 nurses) of 160 married nurses. They worried about adaptation after return to work (30.7%) and complained about disadvantages related to using parental leave (45.3%). The percentage of nurses on leave replaced by new full time nurses was 70.7%. Nurses' awareness (β=.16) of perceived ease of using parental leave (β=.32) influenced the nurses' job satisfaction (R2=.21). CONCLUSION: To improve job satisfaction for nurses, it is necessary to increase awareness and perceived ease of using parental leave. Public hospitals should replace nurses on leave with temporary nurses and help returning nurses adapt to their jobs as they return to work. Nursing managers should create a healthy climate in which it is easy for nurses to take parental leave.

Oral Administration of Silk Peptide Enhances the Maturation and Cytolytic Activity of Natural Killer Cells

Silk peptide, the hydrolysate of silk protein derived from cocoons, has been employed as a biomedical material and is believed to be safe for human use. Silk peptide display various bioactivities, including anti-inflammatory, immune-regulatory, anti-tumor, anti-viral, and anti-bacterial. Although earlier investigations demonstrated that silk peptide stimulates macrophages and the production of pro-inflammatory cytokines, its effect on natural killer (NK) cell function has not yet been explored. In this study, we initially confirmed that silk peptide enhances NK cell activity in vitro and ex vivo. To assess the modulatory activity of silk peptide on NK cells, mice were fed various amounts of a silk peptide-supplemented diet for 2 months and the effects on immune stimulation, including NK cell activation, were evaluated. Oral administration of silk peptide significantly enhanced the proliferation of mitogen- or IL-2-stimulated splenocytes. In addition, oral silk peptide treatment enhanced the frequency and degree of maturation of NK cells in splenocytes. The same treatment also significantly enhanced the target cell cytolytic activity of NK cells, which was determined by cell surface CD107a expression and intracellular interferon-γ expression. Finally, oral administration of silk peptide stimulated T helper 1-type cytokine expression from splenic lymphocytes. Collectively, our results suggest that silk peptide potentiates NK cell activity in vivo and could be used as a compound for immune-modulating anti-tumor treatment.

N-terminal Domain of the Spike Protein of Porcine Epidemic Diarrhea Virus as a New Candidate Molecule for a Mucosal Vaccine

Porcine epidemic diarrhea virus (PEDV) is a contagious coronavirus infecting pigs that leads to significant economic losses in the swine industry. Given that PEDV infection occurs in gut epithelial cells mainly via the fecal-oral route, induction of PEDV-specific immune responses in the mucosal compartment is required for protective immunity against viral infection. However, an effective mucosal vaccine against the currently prevalent PEDV strain is not available. In this study, we demonstrated that the N-terminal domain (NTD) of the spike (S) protein of PEDV represents a new vaccine candidate molecule to be applied via the mucosal route. We first established an Escherichia coli expression system producing the partial NTD (NTD231–501) of the PEDV S protein. Orally administered NTD231–501 protein specifically interacted with the apical area of M cells in the follicle-associated epithelium of Peyer's patch. Additionally, the NTD protein induced antigen-specific immune responses in both the systemic and mucosal immune compartments when administered orally. Collectively, we propose the NTD of the PEDV S protein to be a candidate mucosal vaccine molecule.

Satisfaction with life and the risk of occupational injury

BACKGROUND: Occupational injuries increase burden on society as well as personal health. Low satisfaction with life may not only increases the risk of occupational injuries directly, but also influences other factors that increase the risk of occupational injury. Along with previous studies on the risk of occupational injury, we sought to explore the relationship between satisfaction with life and occupational injury. METHODS: The study participants were 6234workers health screened at a university hospital in Incheon. Information on occupational injury and satisfaction with life scale (SWLS) was obtained in a self-report format. Participants were allocated to one of four SWLS groups; the dissatisfied group, the slightly dissatisfied group, the slightly satisfied group, and the satisfied group. The analysis was performed using the chi-square test primarily and by logistic regression adjusted for potential confounders. RESULTS: In men, the un-adjusted and adjusted odds ratios (ORs) of low satisfaction with life (SWLS< 20) were 1.98(CI1.55–2.53) and 1.81(CI 1.41–2.32), respectively. When the SWLS were divided into four groups, the adjusted ORs of the slightly satisfied (20–25), slightly dissatisfied(15–19), and dissatisfied(≤14) groups were 1.21, 1.72, and 2.70, respectively. That is ORs tended to increase linearly with decreasing SWLS score (p for trend < 0.001). In women, this relation was of borderline significance at best. When subjects were dichotomized based on SWLS scores, for males, the cured and adjusted RRs of occupational injury in the low satisfaction with life group were1.91 (95% CI: 1.50–2.42) and 1.66 (95% CI: 1.30–2.13), and for females, the adjusted-RR was marginally significant (1.67; 95% CI: 0.93–2.99). When subjects were divided into four groups by SWLS scores, adjusted RRs tended to increase linearly with decreasing SWLS score for males (slightly satisfied: 1.18, 95% CI: 0.77–1.82; slightly dissatisfied: 1.65, 95% CI: 1.08–2.52; dissatisfied: 2.22, 95% CI: 1.44–3.42; p for trend < 0.001) and for females (slightly satisfied: 1.17, 95% CI: 0.42–3.30; slightly dissatisfied: 1.56, 95% CI: 0.56–4.36; dissatisfied: 2.38, 95% CI: 0.84–6.74; p for trend = 0.040). CONCLUSIONS: This study suggests that the risk of occupational injury was higher in workers not satisfied with life, and indicates attention to satisfaction with life may promote the health of workers.

Yersinia enterocolitica Exploits Signal Crosstalk between Complement 5a Receptor and Toll-like Receptor 1/2 and 4 to Avoid the Bacterial Clearance in M cells

In the intestinal mucosal surface, microfold cells (M cells) are the representative gateway for the uptake of luminal antigens. At the same time, M cells are the primary infection site for pathogens invading mucosal surface for their infection. Although it is well recognized that many mucosal pathogens exploit the M cells for their infection, the mechanism to infect M cells utilized by pathogens is not clearly understood yet. In this study, we found that M cells expressing complement 5a (C5a) receptor (C5aR) also express Toll-like receptor (TLR) 1/2 and TLR4. Infection of Yersinia enterocolitica, an M cell-invading pathogen, synergistically regulated cyclic adenosine monophosphate-dependent protein kinase A (cAMP-PKA) signaling which are involved in signal crosstalk between C5aR and TLRs. In addition, Y. enterocolitica infection into M cells was enhanced by C5a treatment and this enhancement was abrogated by C5a antagonist treatment. Finally, Y. enterocolitica infection into M cells was unsuccessful in C5aR knock-out mice. Collectively, we suggest that exploit the crosstalk between C5aR and TLR signaling is one of infection mechanisms utilized by mucosal pathogens to infect M cells.