Prevalence and factors associated with digital addiction among students taking university entrance tests: a GIS-based study.

BACKGROUND: The surge in digital media consumption, coupled with the ensuing consequences of digital addiction, has witnessed a rapid increase, particularly after the initiation of the COVID-19 pandemic. Despite some studies exploring specific technological addictions, such as internet or social media addiction, in Bangladesh, there is a noticeable gap in research focusing on digital addiction in a broader context. Thus, this study aims to investigate digital addiction among students taking the university entrance test, examining its prevalence, contributing factors, and geographical distribution using GIS techniques. METHODS: Data from a cross-sectional survey were collected from a total of 2,157 students who were taking the university entrance test at Jahangirnagar University, Bangladesh. A convenience sampling method was applied for data collection using a structured questionnaire. Statistical analyses were performed with SPSS 25 Version and AMOS 23 Version, whereas ArcGIS 10.8 Version was used for the geographical distribution of digital addiction. RESULTS: The prevalence of digital addiction was 33.1% (mean score: 16.05 ± 5.58). Those students who are attempting the test for a second time were more likely to be addicted (42.7% vs. 39.1%), but the difference was not statistically significant. Besides, the potential factors predicted for digital addiction were student status, satisfaction with previous mock tests, average monthly expenditure during the admission test preparation, and depression. No significant difference was found between digital addiction and districts. However, digital addiction was higher in the districts of Manikganj, Rajbari, Shariatpur, and Chittagong Hill Tract areas, including Rangamati, and Bandarban. CONCLUSIONS: The study emphasizes the pressing need for collaborative efforts involving educational policymakers, institutions, and parents to address the growing digital addiction among university-bound students. The recommendations focus on promoting alternative activities, enhancing digital literacy, and imposing restrictions on digital device use, which are crucial steps toward fostering a healthier digital environment and balanced relationship with technology for students.

Exploring the burden of postpartum depression in urban Bangladesh: Prevalence and its associations with pregnancy-related factors from a cross-sectional study.

Background and Aims: Postpartum depression (PPD) is a globally recognized public health concern, yet research focusing on women in urban areas of Bangladesh remains unexplored. This study aimed to address this research gap by investigating the prevalence and associated factors of PPD within the first 2 years after childbirth. Methods: A cross-sectional study was conducted, enrolling 259 women (26.66 ± 4.57 years) residing in urban areas who were attending healthcare delivery centers. Sociodemographic factors, child-related issues, pregnancy-related complications, and PPD using the Edinburgh Postnatal Depression Scale (EPDS) were used for data collection. Data analysis involved the application of χ 2 tests and logistic regression analysis using SPSS software. Results: This study found a 60.6% prevalence of PPD using a cutoff of 10 (out of 30) on the EPDS scale. Logistic regression analysis identified several significant factors associated with PPD, including high monthly family income (odds ratio [OR] = 47.51, 95% confidence interval [CI]: 8.34-270.54, p < 0.001), income dissatisfaction (OR = 14.28, 95% CI: 4.75-42.87, p < 0.001), up to two gravidities (OR = 2.94, 95% CI = 1.25-6.90, p = 0.013), pregnancy-related complications (OR = 2.70, 95% CI = 1.05-6.96, p = 0.039), increased antenatal care visits, and higher childbirth expenses. Conclusion: This study underscores the high prevalence of PPD among urban mothers in Bangladesh. The identified risk factors emphasize the need for targeted mental health initiatives, specifically tailored to support the vulnerable group. Implementing such initiatives can effectively address the challenges posed by PPD and enhance the well-being of postpartum women in urban areas.

Self-Medication Practices among Adult Population in Bangladesh: A Cross-Sectional Study.

BACKGROUND: The practice of self-medication (SM) is common worldwide and is an important component of medical self-care. However, improper practice can be dangerous. This study aimed to estimate the prevalence of SM and the factors associated with it among Bangladeshi adults. METHODS: A cross-sectional survey was conducted between April and June 2021 among Bangladeshi adults (aged > 19 years) using convenient sampling. A total of 1320 subjects were collected through face-to-face interviews using a standardized questionnaire. Multivariable logistic regression analysis was used to identify factors associated with the practice of SM. RESULTS: Overall, 41% of adults in our survey reported SMP. The most common illnesses that prompted SM were common cold/flu (66.4%), gastric problems (65%), and headache (64.4%). The most frequent reasons for SM were to get better-perceived quality of care (30.6%), perceiving SM without side effects (23.3%), and saving time with effectiveness (14.56%). Potential risk factors included 10 years (AOR = 1.91; 95% CI: 1.04-3.50) and >12 years of schooling (AOR = 5.03; 95% CI: 2.27-11.15), being a businessman (AOR = 4.64; 95% CI: 1.74-12.37), having ≤6 family members (AOR = 2.13; 95% CI: 1.40-3.24), being a member of a social group (AOR = 1.53; 95% CI: 1.10-2.12), a health status check after every six months (AOR = 1.52; 95% CI: 1.08-2.13), and current ill-health (AOR = 1.41; 95% CI: 1.06-1.87). Protective factors identified included ≤30 years of age (AOR = 0.40; 95% CI: 0.17-0.93), and practice of modern (AOR = 0.39; 95% CI: 0.22-0.69) and herbal (AOR = 0.45; 95% CI: 0.21-0.97) treatment modality. CONCLUSION: More than one-third of the study participants reported practicing SM. Increasing the community's awareness of the adverse outcomes of SM and not just the average experience might sway individuals away from SM, and implementing strict jurisdiction could be a way to minimize inappropriate SM.

Determinants of food safety knowledge and practices among food handlers in Bangladesh: An institution-based cross-sectional study.

The engagement of a large number of people in big-scale cooking raises the danger of food contamination due to incorrect handling, whether deliberate or unintentional. Contamination during large-scale production poses a serious hazard to consumer health and has significant financial implications for a nation. This study aimed to investigate the food safety knowledge and practices of institutional food handlers in Bangladesh, considering the growing concern surrounding this issue and the lack of available information on foodborne illnesses related to institutions. In addition, the study aimed to determine the factors influencing both knowledge and practices. A cross-sectional study was conducted from June to September 2022, involving 408 institutional food handlers. The sample size was determined using Cochran's formula, and data was collected through purposive sampling. The participants were interviewed in person and completed a pilot-tested questionnaire. A multiple linear regression analysis was conducted to determine the factors related to food safety knowledge and practices. The majority of participants were female (71.3%) and aged between 26 and 35 (mean age 34.53 ± 9.06 years). They were most knowledgeable about hand hygiene and food separation but lacked knowledge about foodborne pathogens and food storage. Thawing food at room temperature was the most inappropriate practice (86%). The mean scores for knowledge and practice were found to be 16.11 ± 2.76 on a 26-point scale (61%), and 9.59 ± 2.07 on a 15-point scale (64%), respectively. Rural food handlers, those with higher education, working more than 10 h per day, and being familiar with HACCP, had higher knowledge. Food handlers aged 18 to 25, with higher income, working in private institutions, having food safety authority knowledge, actively engaging in food safety training, working more than 10 h per day, and having a positive health perception, had better food safety practices.The results of this study reinforce the notion that institutional food handlers would benefit from enhanced exposure to food safety interventions, active participation in training sessions, and strict adherence to food hygiene regulations in their food handling knowledge and practices.

Foodborne pathogens awareness and food safety knowledge of street-vended food consumers: A case of university students in Ghana.

Food pathogens, such as bacteria, viruses, and parasites are agents present in food or water that can cause foodborne illness. Some of these pathogens have been identified in Ghanaian foods and were responsible for the major foodborne disease outbreaks in Ghana. Thus, the current study assessed the awareness of foodborne pathogens and food safety knowledge of students in Ghana. The study employed non-probability techniques, as well as purposive and convenient techniques, to recruit institutions and students for the study. Out of 803 students, the majority (52.3%) were male, between the ages of 20 and 25 (52.8%), attended Ho Technical University (49.8%), and offered non-science-related courses (45.1%). The majority of the respondents were aware of foodborne pathogens, particularly Staphylococcus aureus (53.4%) and Salmonella typhimurium (53.5%). The mean overall score of foodborne pathogen awareness was 14.36 ± 4.57; the passing rate was 73.6%; tribe, institution, field of study, and level of study all had a significant (p < 0.05) effect on awareness of foodborne pathogens. The mean overall score of food safety knowledge was 12.43 ± 3.27; the passing rate was 77.3%; age, tribe, institution, field of study, and level of study all had a significant (p < 0.05) effect on food safety knowledge. Hence, food safety courses should be extended to all levels of education to increase awareness.

Prevalence and factors associated with depression, anxiety, and stress among people with disabilities during COVID-19 pandemic in Bangladesh: A cross-sectional study.

BACKGROUND: The COVID-19 pandemic has had a profound impact on the mental health of individuals across various populations. People with disabilities (PWDs) are particularly vulnerable to these effects, yet there is a lack of studies investigating the mental health of PWDs in Bangladesh. This study aims to investigate the prevalence of and factors associated with depression, anxiety, and stress among PWDs during the COVID-19 pandemic in Bangladesh. METHODS: Data was collected through interviews with 391 PWDs between December 2020 and February 2021. Demographic information, clinical characteristics, and scores from the Depression, Anxiety, and Stress Scale (DASS-21) were obtained. Chi-square tests and logistic regression analyses were conducted to examine the relationship between psychological measures and potential risk factors. RESULTS: The prevalence was found to be 65.7% for depression, 78.5% for anxiety, and 61.4% for stress, respectively. Several factors were identified as associated with these mental health issues, including gender (male), marital status (being married), low education levels, multiple impairments, comorbid medical illnesses, poor sleep quality, rural residency, hearing disability, disability onset later in life, and testing positive for COVID-19. CONCLUSIONS: The prevalence was found to be 65.7% for depression, 78.5% for anxiety, and 61.4% for stress, respectively. Several factors were identified as associated with these mental health issues, including gender (male), marital status (being married), low education levels, multiple impairments, comorbid medical illnesses, poor sleep quality, rural residency, hearing disability, disability onset later in life, and testing positive for COVID-19.

Prevalence, correlates and common conditions associated with adolescent dietary supplement use: a cross-sectional survey in Bangladesh.

OBJECTIVE: There is a broad spectrum of dietary supplements (DS) and their accessibility worldwide. However, little is known about the prevalence of DS use among Bangladeshi adolescents. This study estimates the prevalence, correlates and common conditions related to DS use. DESIGN: A cross-sectional, convenient sampling strategy was adopted using an interviewer-administered, structured questionnaire. SETTING: Kurigram and Patuakhali districts of Bangladesh. PARTICIPANTS: 702 adolescents aged 10-19 years. RESULTS: The overall prevalence of DS use was 83 %. The majority of participants (93·4 %) agreed that DS were good for health, and 28·3 % reported general health and well-being as the reason for using DS. The most frequently used supplements were multivitamins (38·6 %) and Ca (37 %). DS use was more common among adolescents who had ≤5 siblings, good health status, no chronic diseases, a positive impression that DS are good for health and who had the tendency to encourage DS to others. DS use was also higher among those who received DS information from healthcare providers, professional literature, friends, family and relatives. CONCLUSIONS: The prevalence of DS use is relatively higher among Bangladeshi adolescents compared to Bangladeshi adults and adolescents from other countries, highlighting the inclination towards DS use. Guidelines for safe DS use for adolescents are warranted to control DS use and prevent adverse effects.

Food safety and handling knowledge and practices among university students of Bangladesh: A cross-sectional study.

Our study aimed to examine the practices and knowledge of food handling and safety among 1534 university students in Bangladesh (mean age 22.09 ± 1.78), as well as the relationship between these factors and their academic and demographic backgrounds. Participants in this study were undergraduate and graduate students from four public universities in Bangladesh from different religions, income levels, years and majors of study, residential areas, living alone or not, and whose mothers are working or non-working. The questionnaire included 14 questions on food handling practices and 16 on knowledge. Questions were related to food preparation, hygiene, cross-contamination, and storage. The overall mean score for food handling practices was 34.9% (SD = 13.7), while that of knowledge was 41.8% (SD = 16.5). Female students, those from food-related majors, and those engaged in cooking activities scored significantly higher in the knowledge and practice sections (p < 0.05). Students who lived with their families performed significantly better on the knowledge parts, while those who shared a home with roommates in mess performed significantly better on the practice part (p < 0.05). Students having housewife mothers, personal poisoning experience, and continuous involvement in food purchasing scored significantly higher (p < 0.05) in the practices section but not in the knowledge one. On the other hand, students living in urban areas scored significantly higher (p < 0.05) in the knowledge section but not in the practices one. Our results highlight the importance of educational interventions and initiatives to enhance food safety awareness among Bangladeshi university students.

Suicidal ideation among people with disabilities during the COVID-19 pandemic in Bangladesh: prevalence and associated factors.

BACKGROUND: Evidence from pandemic and pre-pandemic studies conducted globally indicates that people with disabilities (PWDs) have a higher risk for suicidality. However, none of these studies has assessed suicidality among PWDs in Bangladesh. AIMS: The purpose of this study was to determine the prevalence of and factors associated with suicidal ideation among PWDs during the COVID-19 pandemic in Bangladesh. METHOD: Using a snowball sampling technique, a cross-sectional survey was conducted from February to April 2021 among PWDs from six districts in the northern region of Bangladesh. Information related to sociodemographic factors, clinical characteristics, behavioural factors and suicidal ideation was collected. Chi-squared test and logistic regression were used to describe the data and explain the relationship of factors associated with suicidal ideation. RESULTS: The prevalence of COVID-19-related past-year suicidal ideation was 23.9%. The factors associated with suicidal ideation included: age above 35 years, being female, acquiring a disability later in life, lack of sleep and current substance use. In addition, higher education appeared to be a protective factor against suicidal ideation. CONCLUSIONS: This study highlighted that PWDs had an increased risk of suicide; that is, one-fourth of them had past-year suicidal ideation. This may have been because of COVID-19-related restrictions and stressors. Thus, the government and policy makers need to pay more attention to developing effective suicide assessment, treatment and management strategies, especially for at-risk groups, to minimise the impact of the COVID-19 outbreak.

Trends and determinants of taking tetanus toxoid vaccine among women during last pregnancy in Bangladesh: Country representative survey from 2006 to 2019.

BACKGROUND: Tetanus occurring during pregnancy is still an important cause of maternal and neonatal mortality in developing countries. This study estimated the trend of tetanus toxoid (TT) immunization coverage from 2006 to 2019 in Bangladesh, considering socio-demographic, socio-economic, and geospatial characteristics. METHODS: The dataset used in this study was extracted from Multiple Indicator Cluster Surveys (2006, 2012-13, and 2019) including 28,734 women aged between 15-49 years. Data analysis was performed using cross-tabulation and logistic regression methods. Further, the spatial distribution of TT immunization coverage was also depicted. RESULTS: The trend of TT immunization (81.8% in 2006 to 49.3% in 2019) and that of taking adequate doses of TT (67.1% in 2006 to 49.9% in 2019) has gradually decreased throughout the study period. Among the administrative districts, North and South-West regions had lower coverage, and South and West regions had relatively higher coverage of both TT immunization and that of adequate doses. Antenatal TT immunization (any dosage, inadequate or adequate) was significantly associated with lower age (AOR = 3.13, 1.55-6.34), higher education (AOR = 1.20, 1.03-1.40), living in urban areas (AOR = 1.17, 1.03-1.34), having immunization card (AOR = 5.19, 4.50-5.98), using government facilities for birth (AOR = 1.41, 1.06-1.88), and receiving antenatal care (ANC) (AOR = 1.51, 1.35-1.69). In addition, living in urban areas (AOR = 1.31, 1.10-1.55), having immunization cards (AOR = 1.62, 1.36-1.92), and choosing others' homes for birth (AOR = 1.37, 1.07-1.74) were significantly associated with adequate TT immunization. However, higher education (AOR = 0.57, 0.44-0.74), having poor wealth index (AOR = 0.65, 0.50-0.83), and receiving ANC (AOR = 0.76, 0.63-0.92) had lower likelihood of taking adequate TT immunization. CONCLUSIONS: The gradual decline in the TT immunization rate in the present study suggests the presence of variable rates and unequal access to TT immunization, demanding more effective public health programs focusing on high-risk groups to ensure adequate TT immunization.

Temporal distribution of fishery resources in Payra River: relationship with climatological changes, ecological assessment, and threat assessment.

The Payra river is one of the large coastal rivers in Bangladesh which supports incredible fish species and has been affected by extensive human disturbance due to huge fishing pressure. The present study provides information about the temporal diversity of finfish and shellfish concerning climatological variables and ecological pollution along with threat assessment in the Payra river, Bangladesh. During the entire study, a total of 61 species including 56 finfish and 5 shellfish species were recorded under 22 families belonging to 11 orders. The order-wise fish species availability showed that the Perciformes (29.49%) was the dominant order based on species richness. Among them, 4 endangered, 6 vulnerable, 4 near threatened, 42 least concern, and 5 data deficient species were found. During the study period, the average Shannon-Weaver diversity index value was (3.33 ± 0.12) indicating a good spread of fish population in the Payra river. Average Margalef richness index value was found (7.60 ± 0.32), Pielou's evenness index (0.48 ± 0.05), and Simpson dominance index (0.93 ± 0.02) in the Payra river. The dominance and Richness index value indicates a clear water environment with slight pollution in the Payra river. Ten different kinds of fishing gears were identified under 3 major groups including 5 nets, 3 hooks and lines, and 2 traps. Canonical correspondence analysis ordination plot showed that rainfall was the most influencing driving force among the meteorological parameters. The cluster analysis based on the Bray-Curtis similarity matrix showed that the winter season formed a separate cluster. In the recapitulation, the Payra river is a highly productive system that provides a favorable environment for a large variety of finfish and shellfish species assemblages. The findings of the conducted study are expected to be helpful for the respective researchers, policymakers, managers, and conservationists for the sustainable management of this water body and the interconnected surrounding neighboring countries.

Knowledge, Attitudes, and Practices towards COVID-19 among Pregnant Women in Northern Bangladesh: A Community-Based Cross-Sectional Study.

Background: COVID-19, caused by SARS-CoV-2, remains a global public health concern despite the availability of effective antiviral treatment against multiple strains. Studies have shown that pregnant women are more susceptible to COVID-19 due to altered physiology and immunological features. Therefore, this study was designed to investigate pregnant women's knowledge, attitudes, and practice (KAP) to prevent COVID-19 and determine the factors associated with KAP. Methods: A community-based cross-sectional study was conducted among 425 pregnant women in Northern Bangladesh. The samples were obtained using a simple random sampling technique from 5 April to 15 June 2020. The data were collected by face-to-face survey with a structured and pre-tested questionnaire and analyzed using SPSS version 25. Bivariable and multivariable logistic regression analyses were performed, and p-values < 0.05 at 95% CI were considered statistically significant. Results: Overall, the score of KAP among the respondents was 47.76%, 49.41%, and 56.24%, respectively. Participants' area of residence, educational status of the husband, and antenatal care (ANC) visit were significantly associated with the level of knowledge, whereas age, educational status of the husband, number of living children, and knowledge were significant predictors of attitude. The knowledge of COVID-19 was the only predictor associated with the practice. Conclusion: Our study shows that almost half of the participants had poor knowledge, a negative attitude, and poor practices regarding COVID-19. Additional health education programs by healthcare professionals and different media, coordinated and combined efforts of government and individuals' participation will be required to fight the spread of the infection.

Prevalence and factors associated with family planning during COVID-19 pandemic in Bangladesh: A cross-sectional study.

BACKGROUND AND OBJECTIVES: The COVID-19 pandemic has negatively impacted health systems worldwide, including in Bangladesh, limiting access to family planning information (FP) and services. Unfortunately, the evidence on the factors linked to such disruption is limited, and no study has addressed the link among Bangladeshis. This study aimed to examine the socioeconomic, demographic, and other critical factors linked to the use of FP in the studied areas during the COVID-19 pandemic. METHODS: The characteristics of the respondents were assessed using a cross-sectional questionnaire survey and descriptive statistics. The variables that were substantially linked with FP usage were identified using a Chi-square test. In addition, a multivariate logistic regression model was used to identify the parameters linked to FP in the study areas during the COVID-19 pandemic. RESULTS: The prevalence of FP use among currently married 15-49 years aged women was 36.03% suggesting a 23% (approximately) decrease compared to before pandemic data. Results also showed that 24.42% of the respondents were using oral contraceptive pills (OCP) which is lower than before pandemic data (61.7%). Multivariate regression analysis provided broader insight into the factors affecting FP use. Results showed that woman's age, education level of the respondents, working status of the household head, locality, reading a newspaper, FP workers' advice, currently using OCP, ever used OCP, husbands' supportive attitude towards OCP use, duration of the marriage, ever pregnant, the number of children and dead child were significantly associated with FP use in the study areas during COVID-19 pandemic. CONCLUSIONS: This study discusses unobserved factors that contributed to a reduction in FP use and identifies impediments to FP use in Bangladesh during the COVID-19 epidemic. This research further adds to our understanding of FP usage by revealing the scope of the COVID-19 pandemic's impact on FP use in Bangladesh's rural and urban areas.

Collectin Kidney 1 Plays an Important Role in Innate Immunity against Streptococcus pneumoniae Infection.

Collectins are C-type lectins that are involved in innate immunity as pattern recognition molecules. Recently, collectin kidney 1 (CL-K1) has been discovered, and in vitro studies have shown that CL-K1 binds to microbes and activates the lectin complement pathway. However, in vivo functions of CL-K1 against microbes have not been elucidated. To investigate the biological functions of CL-K1, we generated CL-K1 knockout (CL-K1-/-) mice and then performed a Streptococcus pneumoniae infection analysis. First, we found that recombinant human CL-K1 bound to S. pneumoniae in a calcium-dependent manner, and induced complement activation. CL-K1-/- mice sera formed less C3 deposition on S. pneumoniae. Furthermore, immunofluorescence analysis in the wild-type (WT) mice demonstrated that CL-K1 and C3 were localized on S. pneumoniae in infected lungs. CL-K1-/- mice revealed decreased phagocytosis of S. pneumoniae. Consequently, less S. pneumoniae clearance was observed in their lungs. CL-K1-/- mice showed severe pulmonary inflammation and weight loss in comparison with WT mice. Finally, the decreased clearance and severe pulmonary inflammation caused by S. pneumoniae infection might cause higher CL-K1-/- mice lethality. Our results suggest that CL-K1 might play an important role in host protection against S. pneumoniae infection through the activation of the lectin complement pathway.

Three pentraxins C-reactive protein, serum amyloid p component and pentraxin 3 mediate complement activation using Collectin CL-P1.

BACKGROUND: Pentraxins (PTXs) are a superfamily of multifunctional conserved proteins involved in acute-phase responses. Recently, we have shown that collectin placenta 1 (CL-P1) and C-reactive protein (CRP) mediated complement activation and failed to form terminal complement complex (TCC) in normal serum conditions because of complement factor H inhibition. METHODS: We used CL-P1 expressing CHO/ldlA7 cells to study the interaction with PTXs. Soluble type CL-P1 was used in an ELISA assay for the binding, C3 and TCC deposition experiments. Furthermore, we used our previously established CL-P1 expressing HEK293 cells for the C3 fragment and TCC deposition assay. RESULTS: We demonstrated that CL-P1 also bound serum amyloid p component (SAP) and pentraxin 3 (PTX3) to activate the classical pathway and the alternative pathway using factor B. CRP and PTX3 further amplified complement deposition by properdin. We found that CRP and PTX3 recruit CFH, whereas SAP recruits C4 binding protein on CL-P1 expressing cell surfaces to prevent the formation of TCC in normal serum conditions. In addition, depletion of CFH, C4BP and complement factor I (CFI) failed to prevent TCC formation both in ELISA and cell experiments. Furthermore, soluble complement receptor 1, an inhibitor of all complement pathways prevents PTX induced TCC formation. CONCLUSION: Our current study hypothesizes that the interaction of pentraxins with CL-P1 is involved in complement activation. GENERAL SIGNIFICANCE: CL-P1 might generally inhibit PTX induced complement activation and host damage to protect self-tissues.

The collectins CL-L1, CL-K1 and CL-P1, and their roles in complement and innate immunity.

Both the complement system and collectins play important roles in our innate immune system. The collectins, which are characterized by their inclusion of a collagen-like region and a calcium-dependent carbohydrate recognition domain, are pattern recognition molecules and include the well characterized proteins mannan-binding lectin (MBL) and the surfactant proteins SP-A/-D. Collectin liver 1 (CL-L1), collectin kidney 1 (CL-K1) and collectin placenta 1 (CL-P1) are the most recently discovered collectins. Although their function is still under investigation, accumulating information suggests that CL-L1, CL-K1 and CL-P1 play important roles in host defense by recognizing a variety of microorganisms and interacting with effector proteins, including complement components. The recent establishment of the existence of CL-K1 in the circulation in form of heteromeric complexes with CL-L1 (known as CL-LK) and its activation of the lectin pathway via MASPs, drew new attention in the complement biology, which was further strengthened by the observed interactions between CL-P1 and CRP-C1q-factor H or properdin. Deficiency of either CL-K1 or MASP-3 has been demonstrated in 3MC syndrome patients with developmental abnormalities, showing that lectin pathway components, regulation and/or activation are essential during the embryonic development; another feature that they most likely share CL-P1. Herein, we discuss the recent characteristics and roles of the collectins CL-L1, CL-K1 and CL-P1 in the complement system, in innate immunity and their possible association with disease development and pathogenesis.

Collectin CL-P1 utilizes C-reactive protein for complement activation.

BACKGROUND: C-reactive protein (CRP) is a plasma pentraxin family protein that is massively induced as part of the innate immune response to infection and tissue injury. CRP and other pentraxin proteins can activate a complement pathway through C1q, collectins, or on microbe surfaces. It has been found that a lectin-like oxidized LDL receptor 1 (LOX-1), which is an endothelial scavenger receptor (SR) having a C-type lectin-like domain, interacts with CRP to activate the complement pathway using C1q. However it remains elusive whether other lectins or SRs are involved in CRP-mediated complement activation and the downstream effect of the complement activation is also unknown. METHODS: We prepared CHO/ldlA7 cells expressing collectin placenta-1 (CL-P1) and studied the interaction of CRP with cells. We further used ELISA for testing binding between proteins. We tested for C3 fragment deposition and terminal complement complex (TCC) formation on HEK293 cells expressing CL-P1. RESULTS: Here, we demonstrated that CL-P1 bound CRP in a charge dependent manner and the interaction of CRP with CL-P1 mediated a classical complement activation pathway through C1q and additionally drove an amplification pathway using properdin. However, CRP also recruits complement factor H (CFH) on CL-P1 expressing cell surfaces, to inhibit the formation of a terminal complement complex in normal complement serum conditions. GENERAL SIGNIFICANCE: The interaction of collectin CL-P1 with CFH might be key for preventing attack on "self" as a result of complement activation induced by the CL-P1 and CRP interaction.

Scavenger receptor CL-P1 mainly utilizes a collagen-like domain to uptake microbes and modified LDL.

BACKGROUND: Collectins are considered to play a role in host defense via complement activation and opsonization, and are composed of a collagen-like domain and a carbohydrate recognition domain (CRD). Collectin placenta 1 (CL-P1) showed scavenger receptor activity as functions in vitro, and has three candidate domains: a coiled-coil domain, a collagen-like domain and CRD. METHODS: We constructed seven types of CL-P1 deletion mutants to determine the site of each ligand binding domain, and observed whether the specific binding to sugar ligand, microbes, or oxidized LDL decreases or not in cells with CL-P1 deletion mutants and CL-P1 containing mutations of amino acid, respectively. RESULTS: CL-P1 mainly interacted with ligands of microbes through the collagen-like domain and it binds a sugar ligand through the CRD. Additionally it could bind oxidized low density lipoprotein (OxLDL) due to the coiled-coil domain as well as the collagen-like domain. This binding study using mutants at three positively charged sites in the collagen-like domain reveals that the site of R496 K499 K502 plays the most important role in ligand binding functions for microbes and OxLDL. CONCLUSIONS: CL-P1 has three unique functional domains: the collagen-like domain mainly acts against most negatively charged ligands, and the CRD specifically does against sugar substances, while the coiled-coil domain additionally acts on modified LDL. GENERAL SIGNIFICANCE: We considered that the binding activity for various ligands due to the association of a coiled-coil domain, a collagen-like domain and/or a CRD in CL-P1, might play a role in physiological functions in the animal body.