Human transferrin receptor can mediate SARS-CoV-2 infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been detected in almost all organs of coronavirus disease-19 patients, although some organs do not express angiotensin-converting enzyme-2 (ACE2), a known receptor of SARS-CoV-2, implying the presence of alternative receptors and/or co-receptors. Here, we show that the ubiquitously distributed human transferrin receptor (TfR), which binds to diferric transferrin to traffic between membrane and endosome for the iron delivery cycle, can ACE2-independently mediate SARS-CoV-2 infection. Human, not mouse TfR, interacts with Spike protein with a high affinity (KD ~2.95 nM) to mediate SARS-CoV-2 endocytosis. TfR knock-down (TfR-deficiency is lethal) and overexpression inhibit and promote SARS-CoV-2 infection, respectively. Humanized TfR expression enables SARS-CoV-2 infection in baby hamster kidney cells and C57 mice, which are known to be insusceptible to the virus infection. Soluble TfR, Tf, designed peptides blocking TfR-Spike interaction and anti-TfR antibody show significant anti-COVID-19 effects in cell and monkey models. Collectively, this report indicates that TfR is a receptor/co-receptor of SARS-CoV-2 mediating SARS-CoV-2 entry and infectivity by likely using the TfR trafficking pathway.

Hypoxia and low temperature upregulate transferrin to induce hypercoagulability at high altitude.

Studies have shown significantly increased thromboembolic events at high altitude. We recently reported that transferrin could potentiate blood coagulation, but the underlying mechanism for high altitude-related thromboembolism is still poorly understood. Here, we examined the activity and concentration of plasma coagulation factors and transferrin in plasma collected from long-term human residents and short-stay mice exposed to varying altitudes. We found that the activities of thrombin and factor XIIa (FXIIa) along with the concentrations of transferrin were significantly increased in the plasma of humans and mice at high altitudes. Furthermore, both hypoxia (6% O2) and low temperature (0°C), 2 critical high-altitude factors, enhanced hypoxia-inducible factor 1α (HIF-1α) levels to promote the expression of the transferrin gene, whose enhancer region contains HIF-1α binding site, and consequently, to induce hypercoagulability by potentiating thrombin and FXIIa. Importantly, thromboembolic disorders and pathological insults in mouse models induced by both hypoxia and low temperature were ameliorated by transferrin interferences, including transferrin antibody treatment, transferrin downregulation, and the administration of our designed peptides that inhibit the potentiation of transferrin on thrombin and FXIIa. Thus, low temperature and hypoxia upregulated transferrin expression-promoted hypercoagulability. Our data suggest that targeting the transferrin-coagulation pathway is a novel and potentially powerful strategy against thromboembolic events caused by harmful environmental factors under high-altitude conditions.

Orientational Nanoconjugation with Gold Endows Marked Antimicrobial Potential and Drugability of Ultrashort Dipeptides.

Antibiotic resistance is a global threat. Antimicrobial peptides (AMPs) are highly desirable to treat multidrug-resistant pathogen infection. However, few AMPs are clinically available, due to high cost, instability, and poor selectivity. Here, ultrashort AMPs (2-3 residues with an N-terminal cysteine) are designed and assembled as gold nanoparticles. Au-S conjugation and ultrashort size restrict nonspecific reactions and peptide orientation, thus concentrating positively charged residues on the surface. The nanostructured assemblies enormously enhance antimicrobial abilities by 1000-6000-fold and stability. One representative (Au-Cys-Arg-NH2, Au_CR) shows selective antibacterial activity against Staphylococcus aureus with 10 nM minimal inhibitory concentration. Au_CR has comparable or better in vivo antimicrobial potency than vancomycin and methicillin, with low propensity to induce resistance, little side effects, and high stability (17.5 h plasma half-life). Au_CR acts by inducing collapse of membrane potential and rupture of the bacterial membrane. The report provides insights for developing AMP-metal nanohybrids, particularly tethering nonspecific reactions and AMP orientation on the metal surface.

Blap-6, a Novel Antifungal Peptide from the Chinese Medicinal Beetle Blaps rhynchopetera against Cryptococcus neoformans.

Cryptococcus neoformans (C. neoformans) is a pathogenic fungus that can cause life-threatening meningitis, particularly in individuals with compromised immune systems. The current standard treatment involves the combination of amphotericin B and azole drugs, but this regimen often leads to inevitable toxicity in patients. Therefore, there is an urgent need to develop new antifungal drugs with improved safety profiles. We screened antimicrobial peptides from the hemolymph transcriptome of Blaps rhynchopetera (B. rhynchopetera), a folk Chinese medicine. We found an antimicrobial peptide named blap-6 that exhibited potent activity against bacteria and fungi. Blap-6 is composed of 17 amino acids (KRCRFRIYRWGFPRRRF), and it has excellent antifungal activity against C. neoformans, with a minimum inhibitory concentration (MIC) of 0.81 µM. Blap-6 exhibits strong antifungal kinetic characteristics. Mechanistic studies revealed that blap-6 exerts its antifungal activity by penetrating and disrupting the integrity of the fungal cell membrane. In addition to its direct antifungal effect, blap-6 showed strong biofilm inhibition and scavenging activity. Notably, the peptide exhibited low hemolytic and cytotoxicity to human cells and may be a potential candidate antimicrobial drug for fungal infection caused by C. neoformans.

Human antimicrobial peptide LL-37 contributes to Alzheimer's disease progression.

As a prime mover in Alzheimer's disease (AD), microglial activation requires membrane translocation, integration, and activation of the metamorphic protein chloride intracellular channel 1 (CLIC1), which is primarily cytoplasmic under physiological conditions. However, the formation and activation mechanisms of functional CLIC1 are unknown. Here, we found that the human antimicrobial peptide (AMP) LL-37 promoted CLIC1 membrane translocation and integration. It also activates CLIC1 to cause microglial hyperactivation, neuroinflammation, and excitotoxicity. In mouse and monkey models, LL-37 caused significant pathological phenotypes linked to AD, including elevated amyloid-ß, increased neurofibrillary tangles, enhanced neuronal death and brain atrophy, enlargement of lateral ventricles, and impairment of synaptic plasticity and cognition, while Clic1 knockout and blockade of LL-37-CLIC1 interactions inhibited these phenotypes. Given AD's association with infection and that overloading AMP may exacerbate AD, this study suggests that LL-37, which is up-regulated upon infection, may be a driving force behind AD by acting as an endogenous agonist of CLIC1.

The 14-3-3ζ-c-Src-integrin-ß3 complex is vital for platelet activation.

Several adaptor molecules bind to cytoplasmic tails of ß-integrins and facilitate bidirectional signaling, which is critical in thrombosis and hemostasis. Interfering with integrin-adaptor interactions spatially or temporally to inhibit thrombosis without affecting hemostasis is an attractive strategy for the development of safe antithrombotic drugs. We show for the first time that the 14-3-3ζ-c-Src-integrin-ß3 complex is formed during platelet activation. 14-3-3ζ-c-Src interaction is mediated by the -PIRLGLALNFSVFYYE- fragment (PE16) on the 14-3-3ζ and SH2-domain on c-Src, whereas the 14-3-3ζ-integrin-ß3 interaction is mediated by the -ESKVFYLKMKGDYYRYL- fragment (EL17) on the 14-3-3ζ and -KEATSTF- fragment (KF7) on the ß3-integrin cytoplasmic tail. The EL17-motif inhibitor, or KF7 peptide, interferes with the formation of the 14-3-3ζ-c-Src-integrin-ß3 complex and selectively inhibits ß3 outside-in signaling without affecting the integrin-fibrinogen interaction, which suppresses thrombosis without causing significant bleeding. This study characterized a previously unidentified 14-3-3ζ-c-Src-integrin-ß3 complex in platelets and provided a novel strategy for the development of safe and effective antithrombotic treatments.

Iron-Deficiency and Estrogen Are Associated With Ischemic Stroke by Up-Regulating Transferrin to Induce Hypercoagulability.

RATIONALE: Epidemiological studies have identified an associate between iron deficiency (ID) and the use of oral contraceptives (CC) and ischemic stroke (IS). To date, however, the underlying mechanism remains poorly understood. Both ID and CC have been demonstrated to upregulate the level and iron-binding ability of Tf (transferrin), with our recent study showing that this upregulation can induce hypercoagulability by potentiating FXIIa/thrombin and blocking antithrombin-coagulation proteases interactions. OBJECTIVE: To investigate whether Tf mediates IS associated with ID or CC and the underlying mechanisms. METHODS AND RESULTS: Tf levels were assayed in the plasma of IS patients with a history of ID anemia, ID anemia patients, venous thromboembolism patients using CC, and ID mice, and in the cerebrospinal fluid of some IS patients. Effects of ID and estrogen administration on Tf expression and coagulability and the underlying mechanisms were studied in vivo and in vitro. High levels of Tf and Tf-thrombin/FXIIa complexes were found in patients and ID mice. Both ID and estrogen upregulated Tf through hypoxia and estrogen response elements located in the Tf gene enhancer and promoter regions, respectively. In addition, ID, administration of exogenous Tf or estrogen, and Tf overexpression promoted platelet-based thrombin generation and hypercoagulability and thus aggravated IS. In contrast, anti-Tf antibodies, Tf knockdown, and peptide inhibitors of Tf-thrombin/FXIIa interaction exerted anti-IS effects in vivo. CONCLUSIONS: Our findings revealed that certain factors (ie, ID and CC) upregulating Tf are risk factors of thromboembolic diseases decipher a previously unrecognized mechanistic association among ID, CC, and IS and provide a novel strategy for the development of anti-IS medicine by interfering with Tf-thrombin/FXIIa interactions.

The antimicrobial peptide ZY4 combats multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii infection.

The emergence of carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa raises fears of untreatable infections and poses the greatest health threats. Antimicrobial peptides (AMPs) are regarded as the most ideal solution to this menace. In this study, a set of peptides was designed based on our previously reported peptide cathelicidin-BF-15, and the lead peptide ZY4, a cyclic peptide stabilized by a disulfide bridge with high stability in vivo (the half-life is 1.8 h), showed excellent activity against P. aeruginosa and A. baumannii, including standard and clinical multidrug-resistant (MDR) strains. ZY4 killed bacteria by permeabilizing the bacterial membrane and showed low propensity to induce resistance, exhibited biofilm inhibition and eradication activities, and also killed persister cells. Notably, administration of ZY4 decreased susceptibility to lung infection by P. aeruginosa and suppressed dissemination of P. aeruginosa and A. baumannii to target organs in a mouse septicemia infection model. These findings identify ZY4 as an ideal candidate against MDR bacterial infections.

Biology, pathotype, and virulence of Globodera rostochiensis populations from Kenya.

The potato cyst nematodes (PCN), Globodera rostochiensis (Woll.) and G. pallida (Stone), are important pests of potato globally. Due to their extensive damage potential and the challenge of managing them, these nematodes are under strict regulations in many countries; however, despite these regulations, PCN continue to spread into new areas and countries. In Kenya, G. rostochiensis was first reported in 2015 and G. pallida was reported three years later, both in Nyandarua County. Research was conducted to characterize the biology, pathotype, and virulence of G. rostochiensis populations from Kenya in glasshouse and laboratory studies. The development of G. rostochiensis was assessed in roots of susceptible potato 'Désirée' and resistant 'Laura' carrying the H1 resistance gene. The 'HAR1' population from Kenya and 'Ecosse' from Germany were not able to produce females in the roots of the resistant potato 'Laura'. The rate of root penetration by G. rostochiensis juveniles did not differ (p > 0.05) between populations and cultivars. However, in the resistant cultivar, juveniles developed into males only. A total of 736 cumulative degree-days at 6°C base temperature (DD6) were required by 'HAR1' to complete the life cycle on 'Désirée', whereas 'Ecosse' completed the life cycle within 645 DD6. The Kenyan populations lacked obligatory diapause and high numbers of juveniles hatched immediately after maturity. Consequently, the Kenyan populations had the potential to complete up to three reproduction cycles in less than a year. On selected potato cultivars, the populations from Kenya failed to reproduce on 10 out of 13 commercial cultivars tested. The 10 cultivars carried the H1 resistance gene, which suggests that the G. rostochiensis populations tested belong to the Ro1/4 pathotype group. The virulence of the G. rostochiensis populations from Kenya did not differ from that of the standard reference population 'Ecosse' and therefore can be effectively managed with the commercially available potato cultivars carrying the H1 resistance gene.

Perspectives on implementing a quality improvement collaborative to improve person-centered care for maternal and reproductive health in Kenya.

OBJECTIVE: To understand perspectives and experiences related to participation in a quality improvement collaborative (QIC) to improve person-centered care (PCC) for maternal health and family planning (FP) in Kenya. DESIGN AND SETTING: Semi-structured qualitative interviews were conducted with members of the QIC in four public health facilities in Kenya. PARTICIPANTS: Clinical and nonclinical public health facility staff who had participated in the QIC were purposively sampled to participate in the semi-structured interviews. INTERVENTION: A QIC was implemented across four public health facilities in Nairobi and Kiambu Counties in Kenya to improve PCC experiences for women seeking maternity or FP services. MAIN OUTCOME MEASURE: Semi-structured interviews with participants of the QIC to understand perspectives and experiences associated with sensitization to and implementation of PCC behaviors in maternity and FP services. RESULTS: Respondents reported that sensitization to PCC principles resulted in multiple perceived benefits for staff and patients alike, including improved interactions with patients and clients, deeper awareness of patient and client preferences, and improved interpersonal skills and greater job satisfaction. Respondents also highlighted system-level challenges that impeded their ability to consistently provide high-quality PCC to women, namely staff shortages and frequent turnover, high patient volumes and lack of space in their respective health facilities. CONCLUSION: Respondents were easily able to articulate perceived benefits derived from participation in this QIC, although they were equally able to identify challenges that hindered their ability to consistently provide high-quality PCC to women seeking maternity or FP services.

Europe as a secondary distribution hub in the worldwide invasion of the potato cyst nematode Globodera rostochiensis.

The potato cyst nematode Globodera rostochiensis originates from the Andean Mountain region in South America and has unintentionally been introduced to all inhabited continents. Several studies have examined the population genetic structure of this pest in various countries by using microsatellite markers. However, merging microsatellite data produced from different laboratories is challenging and can introduce uncertainty when interpreting the results. To overcome this challenge and to explore invasion routes of this pest, we have genotyped 22 G. rostochiensis populations from all continents. Within populations, the highest genetic diversity was observed in the South American populations, the European populations showed an intermediate level of genetic diversity and the remaining populations were the less diverse. This confirmed pre-existing knowledge such as a first introduction event from South America to Europe, but the less diverse populations could originate either from South America or from Europe. At the continental scale, STRUCTURE genetic clustering output indicated that North America and Asia have experienced at least two introduction events. Comparing different evolutionary scenarios, the Approximate Bayesian Computation analysis showed that Europe served as a secondary distribution centre for the invasion of G. rostochiensis into all other continents (North America, Africa, Asia and Oceania).

Transferrin Is Up-Regulated by Microbes and Acts as a Negative Regulator of Immunity to Induce Intestinal Immunotolerance.

Cross-talks (e.g., host-driven iron withdrawal and microbial iron uptake between host gastrointestinal tract and commensal microbes) regulate immunotolerance and intestinal homeostasis. However, underlying mechanisms that regulate the cross-talks remain poorly understood. Here, we show that bacterial products up-regulate iron-transporter transferrin and transferrin acts as an immunosuppressor by interacting with cluster of differentiation 14 (CD14) to inhibit pattern recognition receptor (PRR) signaling and induce host immunotolerance. Decreased intestinal transferrin is found in germ-free mice and human patients with ulcerative colitis, which are characterized by impaired intestinal immunotolerance. Intestinal transferrin and host immunotolerance are returned to normal when germ-free mice get normal microbial commensalism, suggesting an association between microbial commensalism, transferrin, and host immunotolerance. Mouse colitis models show that transferrin shortage impairs host's tolerogenic responses, while its supplementation promotes immunotolerance. Designed peptide blocking transferrin-CD14 interaction inhibits immunosuppressive effects of transferrin. In monkeys with idiopathic chronic diarrhea, transferrin shows comparable or even better therapeutic effects than hydrocortisone. Our findings reveal that by up-regulating host transferrin to silence PRR signaling, commensal bacteria counteract immune activation induced by themselves to shape host immunity and contribute for intestinal tolerance.

Biocompatible and Biodegradable 3D Printing from Bioplastics: A Review.

There has been a lot of interest in developing and producing biodegradable polymers to address the current environmental problem caused by the continued usage of synthetic polymers derived from petroleum products. Bioplastics have been identified as a possible alternative to the use of conventional plastics since they are biodegradable and/or derived from renewable resources. Additive manufacturing, also referred to as 3D printing, is a field of growing interest and can contribute towards a sustainable and circular economy. The manufacturing technology also provides a wide material selection with design flexibility increasing its usage in the manufacture of parts from bioplastics. With this material flexibility, efforts have been directed towards developing 3D printing filaments from bioplastics such as Poly (lactic acid) to substitute the common fossil- based conventional plastic filaments such as Acrylonitrile butadiene styrene. Plant biomass is now utilized in the development of biocomposite materials. A lot of literature presents work done toward improving the biodegradability of printing filaments. However, additive manufacture of biocomposites from plant biomass is faced with printing challenges such as warping, low agglomeration between layers and poor mechanical properties of the printed parts. The aim of this paper is to review the technology of 3D printing using bioplastics, study the materials that have been utilized in this technology and how challenges of working with biocomposites in additive manufacture have been addressed.

Design methods for antimicrobial peptides with improved performance.

The recalcitrance of pathogens to traditional antibiotics has made treating and eradicating bacterial infections more difficult. In this regard, developing new antimicrobial agents to combat antibiotic-resistant strains has become a top priority. Antimicrobial peptides (AMPs), a ubiquitous class of naturally occurring compounds with broad-spectrum antipathogenic activity, hold significant promise as an effective solution to the current antimicrobial resistance (AMR) crisis. Several AMPs have been identified and evaluated for their therapeutic application, with many already in the drug development pipeline. Their distinct properties, such as high target specificity, potency, and ability to bypass microbial resistance mechanisms, make AMPs a promising alternative to traditional antibiotics. Nonetheless, several challenges, such as high toxicity, lability to proteolytic degradation, low stability, poor pharmacokinetics, and high production costs, continue to hamper their clinical applicability. Therefore, recent research has focused on optimizing the properties of AMPs to improve their performance. By understanding the physicochemical properties of AMPs that correspond to their activity, such as amphipathicity, hydrophobicity, structural conformation, amino acid distribution, and composition, researchers can design AMPs with desired and improved performance. In this review, we highlight some of the key strategies used to optimize the performance of AMPs, including rational design and de novo synthesis. We also discuss the growing role of predictive computational tools, utilizing artificial intelligence and machine learning, in the design and synthesis of highly efficacious lead drug candidates.

Diaphragm used with replens gel and risk of bacterial vaginosis: results from a randomized controlled trial.

BACKGROUND: Bacterial vaginosis (BV) has been linked to female HIV acquisition and transmission. We investigated the effect of providing a latex diaphragm with Replens and condoms compared to condom only on BV prevalence among participants enrolled in an HIV prevention trial. METHODS: We enrolled HIV-seronegative women and obtained a vaginal swab for diagnosis of BV using Nugent's criteria; women with BV (score 7-10) were compared to those with intermediate (score 4-6) and normal flora (score 0-3). During quarterly follow-up visits over 12-24 months a vaginal Gram stain was obtained. The primary outcome was serial point prevalence of BV during followup. RESULTS: 528 participants were enrolled; 213 (40%) had BV at enrollment. Overall, BV prevalence declined after enrollment in women with BV at baseline (OR = 0.4, 95% CI 0.29-.56) but did not differ by intervention group. In the intention-to-treat analysis BV prevalence did not differ between the intervention and control groups for women who had BV (OR = 1.01, 95% CI 0.52-1.94) or for those who did not have BV (OR = 1.21, 95% CI 0.65-2.27) at enrollment. Only 2.1% of participants were treated for symptomatic BV and few women (5-16%) were reported using anything else but water to cleanse the vagina over the course of the trial. CONCLUSIONS: Provision of the diaphragm, Replens, and condoms did not change the risk of BV in comparison to the provision of condoms alone.

Land management can contribute to net zero.

The voluntary carbon market needs to embrace changes for the land sector.

Platelet-rich plasma as a therapy for androgenic alopecia: a systematic review and meta-analysis.

OBJECTIVE: The past decade has seen platelet-rich plasma (PRP) become a popular therapy around the world as a treatment for androgenetic alopecia (AGA). These systematic review and meta-analyses assess the effectiveness and adverse effects of PRP to determine the role of PRP as a treatment for AGA among the other non-surgical treatment modalities. METHODS: This study follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and is registered under the PROSPERO ID CRD42019136329. Seven databases were searched from inception through May 2019. Meta-analyses of randomized controlled trials (RCTs) were performed to evaluate the effect of PRP treatments on hair density and hair thickness. RESULTS: Thirty studies, including 687 patients, met our inclusion criteria. Twenty-nine studies reported beneficial results, and 24 studies reached statistical significance on a measured outcome. Ten RCTs were included. Our meta-analyses show that PRP treatment increases hair density and hair thickness. CONCLUSIONS: PRP is an autologous treatment that lacks serious adverse effects and effectively improves hair density and hair thickness in men and women with AGA. Future research should include low risk-of-bias RCTs to optimize treatment protocols, investigate variability among studies, and to obtain more data on hair thickness changes.

Comparative Efficiency for in vitro Transfection of Goat Undifferentiated Spermatogonia Using Lipofectamine Reagents and Electroporation.

Introduction: Spermatogonial stem cells (SSC), also referred to as undifferentiated spermatogonia, are the germline stem cells responsible for continuous spermatogenesis throughout a male's life. They are, therefore, an ideal target for gene editing. Previously, SSC from animal testis have been isolated and transplanted to homologous recipients resulting in the successful reestablishment of donor-derived spermatogenesis. Methods: Enhanced green fluorescent protein (eGFP) gene transfection into goat SSC was evaluated using liposomal carriers and electroporation. The cells were isolated from the prepubertal Galla goats testis cultured in serum-free defined media and transfected with the eGFP gene. Green fluorescing of SSC colonies indicated transfection. Results: The use of lipofectamineTM stem reagent and lipofectamineTM 2000 carriers resulted in more SSC colonies expressing the eGFP gene (25.25% and 22.25%, respectively). Electroporation resulted in 15% ± 0.54 eGFP expressing SSC colonies. Furthermore, cell viability was higher in lipofectamine transfection (55% ± 0.21) as compared to electroporation (38% ± 0.14). Conclusion: These results indicated that lipofectamine was more effective in eGFP gene transfer into SSC. The successful transient transfection points to a possibility of transfecting transgenes into male germ cells in genetic engineering programs.

Potent CaV3.2 channel inhibitors exert analgesic effects in acute and chronic pain models.

Pain is the most common presenting physical symptom and a primary reason for seeking medical care, which chronically affects people's mental health and social life. CaV3.2 channel plays an essential role in the peripheral processing maintenance of pain states. This study was designed to identify novel drug candidates targeting the CaV3.2 channel. Whole-cell patch-clamp, cellular thermal shift assay, FlexStation, in vivo and in vitro CaV3.2 knock-down, site-directed mutagenesis, and double-mutant cycle analysis were employed to explore the pain-related receptors and ligand-receptor direct interaction. We found that toddaculin efficiently inhibits the CaV3.2 channel and significantly reduced the excitability of dorsal root ganglion neurons and pain behaviors. The Carbonyl group of coumarins directly interacts with the pore domain of CaV3.2 via van der Waals (VDW) force. Docking with binding pockets further led us to identify glycycoumarin, which exhibited more potent inhibition on the CaV3.2 channel and better analgesic activity than the parent compound. Toddaculin and its analog showed beneficial therapeutic effects in pain models. Toddaculin binding pocket on CaV3.2 might be a promising docking site for the design of drugs.