Plasmodium falciparum (Pf) 5-aminolevulinic acid synthase (5-ALAS) is an essential enzyme with high selectivity during liver stage development, signifying its potential as a prophylactic antimalarial drug target. The aim of this study was to identify important potential lead compounds which can serve as inhibitors of Pf 5-ALAS using pharmacophore modeling, virtual screening, qualitative structural assessment, in silico ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) evaluation and molecular dynamics simulation. The best model of the tertiary structure of Pf 5-ALAS was obtained using MolProbity, while the following databases were explored for the pharmacophore-based virtual screening: CHEMBL, ChemDiv, ChemSpace, MCULE, MCULE-ULTIMATE, MolPort, NCI Open Chemical Repository, LabNetwork and ZINC databases. 2,621 compounds were screened against the modeled Pf 5-ALAS using AutoDock vina. The post-screening analysis was carried out using Discovery Studio while molecular dynamics simulation was performed on the best hits using NAMD-VMD and Galaxy Europe platform. Compound CSMS00081585868 was observed as the best hit with a binding affinity of -9.9 kcal/mol and predicted Ki of 52.10 nM, engaging in seven hydrogen bonds with the target's active site amino acid residues. The in silico ADMET prediction showed that all ten best hits possessed relatively good pharmacokinetic properties. The qualitative structural assessment of the best hit, CSMS00081585868, revealed that the presence of two pyridine scaffolds bearing hydroxy and fluorine groups linked by a pyrrolidine scaffold contributed significantly to its ability to have a strong binding affinity with the receptor. The best hit also showed stability in the active site of Pf 5-ALAS as confirmed from the RMSD obtained during the MD simulation.

Though effective in treating actinic damage, topical photodynamic therapy (PDT) has been demonstrated to be immunosuppressive through unknown mechanisms, which could potentially limit its effectiveness. Multiple types of environmental stressors including PDT can produce the immunosuppressive lipid mediator Platelet-activating Factor (PAF). As PAF can produce subcellular microvesicle particles (MVP), the present studies tested if PDT can generate PAF and MVP release, and if these are involved in PDT-induced immunosuppression. Previously, topical PDT using blue light and 5-aminolevulinic acid was found to be a potent stimulus for PAF production in mice and human skin explants and human patients, and we show experimental PDT also generates high levels of MVP. PDT-generated MVP were independent of the PAF receptor (PAFR), but, were dependent upon the MVP-generating enzyme acid sphingomyelinase (aSMase). Patients undergoing topical PDT treatment to at least 10% of body surface area demonstrated local and systemic immunosuppression as measured by inhibition of delayed-type hypersensitivity reactions. Finally, using a murine model of contact hypersensitivity, PDT immunosuppression was blocked by genetic and pharmacologic inhibition of aSMase, and genetic inhibition of PAFR signaling. These studies describe a mechanism involving MVP by which PDT exerts immunomodulatory effects, providing a potential target to improve its effectiveness.

Subependymal Giant Cell Astrocytoma (SEGA) is a common diagnosis in patients with Tuberous Sclerosis. Although surgical treatment is often required, resection may entail a significant risk for cognitive function given the anatomical relation with critical structures such as the fornices and subgenual area. Therefore, target subtotal resections using minimal invasive approaches focused in the higher metabolic areas are valuable options to preserve quality of life while addressing specific problems caused by the tumor, such as hydrocephalus or progressive growth of a specific component of the tumor. In this report, the authors explore the potential role of 5-ALA in the identification of highly metabolic areas during SEGA resection in the context of minimal invasive approaches.

Hypertrophic scar is a common problem after skin burns or trauma which brings physical, psychological, and cosmetic problems to patients. Photodynamic therapy with 5-aminolevulinic acid (5-ALA) is a promising therapy for hypertrophic scar. However, clinical applications of 5-ALA are limited because of the low permeability of 5-ALA in the skin stratum corneum and the rapid binding of protoporphyrin IX (PpIX) with iron ions, which lead to insufficient PpIX production in target tissues. Herein, a mixture of 5-ALA and DFO (deferoxamine, a special iron chelator) was applied for the treatment of hypertrophic scar. 5-ALA/DFO could efficiently block the biotransformation of PpIX to heme, thus realizing a significant accumulation of photosensitizer. In addition, injection locally into the lesion was applied, which combined with enhanced photodynamic therapy to destroy hypertrophic scar fibroblasts. In vitro experiments showed that 5-ALA/DFO could increase more ROS generation by increasing the accumulation of PpIX, resulting in the apoptosis of hypertrophic scar fibroblasts. Furthermore, 5-ALA/DFO inhibited the proliferation and migration of hypertrophic scar fibroblasts. In vivo study showed that 5-ALA/DFO could effectively inhibit the formation of proliferative scar. Therefore, 5-ALA/DFO has the potential to enhance the photodynamic therapy of 5-ALA and provides a new treatment strategy for hypertrophic scar.

The Cytochrome P450 (CYP450) superfamily has been the subject of intense research for over six decades. Here the HU227 strain of E. coli, lacking the δ-aminolevulinic acid (δ-ALA) synthase gene, was employed, along with [5-13C] δ-ALA, in the heterologous expression of P450cam harboring a prosthetic group labeled with 13C at the four methine carbons (Cm) and pyrrole Cα positions. The product was utilized as a proof of principle strategy for defining and refining solution phase active site structure in cytochrome P450cam, providing proton-to-proton distances from 13CmH to protons on bound substrate or nearby amino acid residues, using short mixing time 2D or 3D NOESY-HMQC methods. The results reveal the interesting finding that 2D 13C-filtered NOESY-HMQC can be used to obtain distances between protons on labeled 13C to positions of protons nearby in the active site, confirming the utility of this NMR-based approach to probing active site structure under physiological conditions. Such 13C-heme-filtered NOE data complement X-ray crystallographic and T1-based NMR measurements; and, may also be of potentially significant utility in furnishing experimental distance constraints in validations of docking routines commonly employed for determining the relative affinities and binding orientations of drug candidates with CYP450s.

To redirect carbon flux from the γ-aminobutyric acid (GABA) shunt to the δ-aminolevulinic acid (ALA) biosynthetic pathway, we disrupted the GABA shunt route of the model cyanobacterium Synechocystis sp. PCC 6803 by inactivating Gdc, the gene-encoding glutamate decarboxylase. The generated ΔGdc strain exhibited lower intracellular GABA and higher ALA levels than the wild-type (WT) one. The ΔGdc strain's ALA levels were ~2.8 times higher than those of the WT one when grown with levulinic acid (LA), a competitive inhibitor of porphobilinogen synthase. Abiotic stress conditions including salinity induced by 10 mM NaCl and cold at 4 °C increased the ALA levels in ΔGdc up to ~2.5 and 5 ng g-1 cell DW, respectively. The highest ALA production in the ΔGdc cyanobacteria grown in BG11 medium was triggered by glucose induction, followed by glutamate supplementation with 60 mM of LA, thereby resulting in ~360 ng g-1 cell DW of ALA, that is >300-fold higher ALA accumulation than that observed in ΔGdc cyanobacteria grown in normal medium. Increased levels of the gdhA (involved in the interconversion of α-ketoglutarate to glutamate) and the hemA (a major regulatory target of the ALA biosynthetic pathway) transcripts occurred in ΔGdc cyanobacteria grown under modified growth conditions. Our study provides critical insight into the facilitation of ALA production in cyanobacteria.

Photodynamic therapy (PDT) with photosensitization using 5-aminolevulinic acid (ALA) [including a nanoemulsion (BF-200 ALA)] is approved in the USA for the treatment of actinic keratoses (AKs); another derivative, methyl aminolevulinate, is not approved in the USA but is used in Europe. For AK treatment, the photosensitizer may be applied to individual AK lesions or, depending on treatment regimen, to broader areas of sun-damaged skin to manage field cancerization, although not all products are approved for field treatment. ALA-PDT and photosensitizers have also been used off-label for the treatment of nonmelanoma skin cancers, primarily basal cell carcinomas (BCCs) and cutaneous squamous cell carcinomas (cSCC). Advantages of PDT include potentially improved cosmesis and patient satisfaction; disadvantages include pain and duration of treatment. Alternative illumination approaches, including intense pulsed light as well as pulsed-dye lasers, have also been used successfully. Pretreating the affected tissue or warming during incubation can help to increase photosensitizer absorption and improve therapeutic efficacy. Combinations of multiple treatments are also under exploration. Reducing incubation time between photosensitizer application and illumination may significantly reduce pain scores without affecting treatment efficacy. Substituting daylight PDT for a conventional illumination source can also reduce pain without compromising efficacy. The objective of this narrative review is to describe current and ongoing research in the use of topical photosensitizers and modified light delivery regimens to achieve improved therapeutic outcomes with less toxicity in patients with AK, cSCC, BCC, and field cancerization.

To retrospectively explore the characteristics of plasma amino acids (PAAs) in children with autism spectrum disorder and their clinical association via case-control study. A total of 110 autistic and 55 healthy children were recruited from 2014 to 2018. The clinical phenotypes included severity of autism, cognition, adaptability, and regression. Compared with the control group, autistic children had significantly elevated glutamate, γ-Amino-n-butyric acid, glutamine, sarcosine, δ-aminolevulinic acid, glycine and citrulline. In contrast, their plasma level of ethanolamine, phenylalanine, tryptophan, homocysteine, pyroglutamic acid, hydroxyproline, ornithine, histidine, lysine, and glutathione were significantly lower. Elevated neuroactive amino acids (glutamate) and decreased essential amino acids were mostly distinct characteristics of PAAs of autistic children. Increased level of tryptophan might be associated with severity of autism.

Photodynamic therapy (PDT) is a proposed non-invasive, highly effective, and fertility-preserving method for the treatment of lower reproductive tract diseases in women. We aim to evaluate the effect of PDT on complete remission, recurrence, and HPV clearance in diseases of the female lower reproductive tract associated with the human papillomavirus (HPV) infection in this meta-analysis. PubMed, EMBASE, Scopus, Cochrane Library, and China National Knowledge Infrastructure databases were searched to compare PDT with other treatments for complete remission, recurrence, and HPV clearance in women with lower genital tract disease. Fixed or random effect models were performed to assess the pooled effect size. Sensitivity analysis was performed to detect heterogeneity in the included studies. The Begg and Egger test assessed publication bias. There were 12 studies qualified for inclusion; compared to other treatments, PDT had a significant advantage in complete remission (OR=2.97, 95%CI, 2.18-4.04, I2=0, P<0. 001) and recurrence (OR, 0.21; 95%CI, 0.11-0.39; I2=34.9%, P<0. 001). Furthermore, PDT clears HPV quickly and lastingly compared to other therapies (OR, 2.65; 95% CI, 1.41-4.95; I2=71.0%, P=0.002). In addition, the heterogeneity test of sensitivity analysis suggested that the results were robust. Begg test (P=0.73) and Egger test (P=0.71) showed no publication bias. PDT treats diseases of the female lower reproductive tract associated with HPV infection: high complete remission, low recurrence, and rapid and lasting HPV clearance. The PDT seems to be a non-invasive, effective, and promising treatment of female lower reproductive tract diseases associated with HPV infection.

Circulating tumor cells (CTCs) are precursors to cancer metastasis. In blood circulation, they take various forms such as single CTCs, CTC clusters, and CTC-leukocyte clusters, all of which have unique characteristics in terms of physiological function and have been a subject of extensive research in the last several years. Unfortunately, conventional methods are limited in accurately analysing the highly heterogeneous nature of CTCs. Here we present an effective strategy for simultaneously analysing all forms of CTCs in blood by virtual-freezing fluorescence imaging (VIFFI) flow cytometry with 5-aminolevulinic acid (5-ALA) stimulation and antibody labeling. VIFFI is an optomechanical imaging method that virtually freezes the motion of fast-flowing cells on an image sensor to enable high-throughput yet sensitive imaging of every single event. 5-ALA stimulates cancer cells to induce the accumulation of protoporphyrin (PpIX), a red fluorescent substance, making it possible to detect all cancer cells even if they show no expression of the epithelial cell adhesion molecule, a typical CTC biomarker. Although PpIX signals are generally weak, VIFFI flow cytometry can detect them by virtue of its high sensitivity. As a proof-of-principle demonstration of the strategy, we applied cancer cells spiked in blood to the strategy to demonstrate image-based detection and accurate classification of single cancer cells, clusters of cancer cells, and clusters of a cancer cell(s) and a leukocyte(s). To show the clinical utility of our method, we used it to evaluate blood samples of four breast cancer patients and four healthy donors and identified EpCAM-positive PpIX-positive cells in one of the patient samples. Our work paves the way toward the determination of cancer prognosis, the guidance and monitoring of treatment, and the design of antitumor strategies for cancer patients.

The acute hepatic porphyrias (AHP) are rare, inborn errors of heme-metabolism and include acute intermittent porphyria, hereditary coproporphyria, variegate porphyria, and porphyria due to severe deficiency of 5-aminolevulinic acid dehydratase. Acute intermittent porphyria is the most common type of AHP, with an estimated prevalence of patients with symptoms of approximately 1 in 100,000. The major clinical presentation involves attacks of severe pain, usually abdominal and generalized, without peritoneal signs or abnormalities on cross-sectional imaging. Acute attacks occur mainly in women in their childbearing years. AHP should be considered in the evaluation of all patients, and especially women aged 15-50 years with recurrent severe abdominal pain not ascribable to common causes. The screening tests of choice include random urine porphobilinogen and δ-aminolevulinic acid corrected to creatinine. All patients with elevations in urinary porphobilinogen and/or δ-aminolevulinic acid should initially be presumed to have AHP. The cornerstones of management include discontinuation of porphyrinogenic drugs and chemicals, administration of oral or intravenous dextrose and intravenous hemin, and use of analgesics and antiemetics. Diagnosis of AHP type can be confirmed after initial treatment by genetic testing for pathogenic variants in HMBS, CPOX, PPOX, and ALAD genes. AHP is also associated with chronic symptoms and long-term risk of systemic arterial hypertension, chronic renal and liver disease, and hepatocellular carcinoma. Patients who have recurrent acute attacks (4 or more per year) should be considered for prophylactic therapy with intravenous hemin or subcutaneous givosiran. Liver transplantation is curative and reserved for patients with intractable symptoms who have failed other treatment options.

Human papillomavirus (HPV) infection and related diseases are clinical challenges. The efficacy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) using red laser (630 ± 5 nm) is remarkable and safe. In this study, we aim to investigate the efficacy of ALA-450 nm PDT comparing with ALA-635 nm PDT. We detected cell proliferation and cell apoptosis through MTT assay and flow cytometry assay respectively. Flow cytometry assay determined the intracellular reactive oxygen species (ROS) generation. Western blotting analysis investigated the protein expression. In vivo, immunohistochemical staining assay and TUNEL assay were performer to detect cell apoptosis. ALA-450 nm PDT inhibited the proliferation of End1 and HeLa cells, promoted cell apoptosis more effectively than ALA-635 nm PDT, and induced cell death probably through increasing the intracellular ROS generation and caspase-dependent apoptosis pathway. In vivo, ALA-450 nm PDT significantly inhibited tumour growth and activated cell apoptosis. The ALA-450 nm PDT had an advantage over ALA-635 nm PDT on inhibiting the proliferation of End1 and HeLa cells and inducing cell apoptosis. The ALA-450 nm PDT might be a promising therapeutic strategy for eradicating the HR-HPV infected cells and promoting the integration of diagnosis and treatment of HR-HPV related diseases.HighlightsWe combined 5-aminolevulinic acid with 450 nm blue laser using as a novel type of photodynamic therapy.The ALA-450 nm PDT had an advantage over ALA-635 nm PDT on inhibition of the proliferation of End1 and HeLa cells and inducing cell apoptosis in vitro and in vivo.The ALA-450 nm PDT may provide a novel alternative therapeutic option in patients with persistent HPV infection and promote the integration of diagnosis and treatment.

The present study aimed to evaluate the effects of 5-aminolevulinic acid (5-ALA) on Eimeria tenella infection in laying hens. Oocyst shedding and histopathology were evaluated. A reduced oocyst shedding was observed 5 and 7 days post-infection (dpi) in the 5-ALA-administered group, but the total number of oocysts during the first infection period was not different between control and 5-ALA-treated groups. After E. tenella attack infection, the period of oocyst shedding in the 5-ALA-administered group lasted less long than that in controls. During the attack infection period, the total number of fecal oocysts in the 5-ALA-treated group was significantly lower than that in the control group. However, the parasite burden score in hens receiving 5-ALA was higher than that in controls after E. tenella attack infection. The lesion scores at 5 and 30 dpi in the control group were significantly lower than those in the 5-ALA-administered group. Therefore, 5-ALA administration might be beneficial against E. tenella infection in laying hens.

Porphobilinogen deaminase (PBGD) haploinsufficiency (acute intermittent porphyria, AIP) is characterized by neurovisceral attacks associated with high production, accumulation and urinary excretion of heme precursors, δ-aminolevulinic acid (ALA) and porphobilinogen (PBG). The estimated clinical penetrance for AIP is extremely low (<1%), therefore it is likely that other factors may play an important role in the predisposition to developing attacks. Fasting is a known triggering factor. Given the increased prevalence of insulin resistance in patients and the large urinary loss of succinyl-CoA to produce ALA and PBG, we explore the impact of reduced availability of energy metabolites in the severity of AIP pathophysiology. Classic studies found clinical improvement in patients affected by AIP associated with the administration of glucose and concomitant insulin secretion, or after hyperinsulinemia associated with diabetes. Molecular studies have confirmed that glucose and insulin administration induces a repressive effect on hepatic ALA Synthase, the first and regulatory step of the heme pathway. More recently, the insulin-mimicking α-lipoic acid has been shown to improve glucose metabolism and mitochondrial dysfunction in a hepatocyte cell line transfected with interfering RNA targeting PBGD. In AIP mice, preventive treatment with an experimental fusion protein of insulin and apolipoprotein A-I improved the disease by promoting fat mobilization in adipose tissue, increasing the metabolite bioavailability for the TCA cycle and inducing mitochondrial biogenesis in the liver. In this review, we analyze the possible mechanisms underlying abnormal hepatocellular carbohydrate homeostasis in AIP.

Photodynamic therapy (PDT) elicits cell death, vascular damage, or/and anti-tumor host immune response upon activating the administered photosensitive drug by an appropriate light source. Because PDT is heavily dependent on tissue oxygen (O2) in essence, the concentration-dependent impact of O2 on tailoring cellular response to PDT remains an in-depth investigation. As a multifaceted modality, optimal combinations of photosensitizer (PS) concentration, light dose, and O2 delivery are critical to achieve ideal therapeutic outcomes. We herein present a fully integrated all-in-one device for the in vitro assessment of PDT efficacy synchronizing the quantitative control of three PDT disciplines simultaneously, aiming at 1) identifying the influence of varying gaseous microenvironments on PDT; and 2) determining the contribution of each PDT factor and estimating the strength of their synergic effect. The gas-gradient-generating unit for contactless headspace O2 delivery and spatial light control filtering layer in our device could either work as a stand-alone module or combine to screen a range of experimental PDT parameters. By sweeping a total of 128 conditions over four 5-aminolevulinic acid (5-ALA) concentrations, four light dosages, and eight O2 levels in one single experiment, we determined the main effects of the three key PDT agents and highlighted the interactive effect between 5-ALA and light after full-factorial statistical analysis. Our device is not only a versatile tool for predicting PDT efficacy during the translational study but also provides valuable multidimensional information for the interrelation between key PDT factors, which may expedite clinical PDT dosimetry and furnish new insights for the fundamental understanding of photobiological processes.

In dermatology, photodynamic therapy (PDT) is widely used in skin tumors, infections, etc., because of the killing effect triggered by toxic reactive oxygen species (ROS). However, the ROS concentration is determined by various photosensitizer concentrations and formulations, as well as various irradiation parameters. Low-dose PDT leads to sufficiently low ROS level, which results in biological effects that are the exact opposite of the killing potency. Therefore, in recent years, low-dose PDT has been exploited in improving aging and wound. Low-dose ALA/MAL PDT might improve aging through promoting the proliferation of fibroblasts, blocking DNA damage, counteracting oxidative stress, inhibiting melanogenesis, and remodeling lymphatic vessels in aged skin. Promoting fibroblasts and epidermal stem cells proliferation and migration, promoting granulation tissue formation and angiogenesis and regulating the inflammatory process might be the mechanisms of low-dose ALA/MAL PDT in wound healing. Nevertheless, the positive effects of low-dose PDT have not been thoroughly investigated in dermatology, and high-quality studies are still needed to fill the relevant vacancy.

Porphyrias are inborn errors of heme biosynthesis pathway that result in neurovisceral and/ or cutaneous manifestations which occur with episodic attacks, usually accompanied by a multisystemic involvement. Acute hepatic porphyrias include acute intermittent porphyria, variegate porphyria, hereditary coproporphyria, and aminolevulinic acid dehydratase deficiency porphyria. Acute hepatic porphyrias may present with symptoms of an affected central, peripheral, and autonomic nervous system and are generally diagnosed in time of an acute neurovisceral attack. In children, clinical picture is more complicated and presents with neurological findings predominantly. First-line investigation should be the urinary porphobilinogen and aminolevulinic acid performance when acute hepatic porphyria is clinically suspected. Comprehensive testing including urine porphyrin separation, fluorescence scanning of diluted plasma at neutral pH, evaluation of fecal porphyrins, and measurement of erythrocyte porphobilinogen deaminase activity is indicated for confirmation or exclusion of the porphyria and define the type of acute hepatic porphyrias. The main aim of the treatment is to decrease aminolevulinic acid, porphobilinogen, and porphyrins by reducing hepatic ALAS1 activity. The first measure should always be the avoidance of any porphyrinogenic drugs. Hemin therapy should not be delayed in the treatment of a severe acute attack. Gonadotropin-releasing hormone analogs and prophylactic hemin protocols can be used for selected cases with more than 4 attacks per year. Givosiran is a promising treatment option for severe cases.

Severe acne vulgaris is a common chronic inflammatory skin disease worldwide. 5-Aminolaevulinic acid photodynamic therapy (ALA-PDT) is effective and safe for severe acne. However, the mechanism is not fully understood. Intense acute inflammatory response at 24 h after ALA-PDT is reported positively correlated to the effectiveness. Inflammation regulation influence the progression or outcome of diseases. ALA-PDT may exert its therapeutic effect by augmenting intense inflammation and break the chronic inflammation. This study was set out to explore the mechanism of ALA-PDT augmenting intense acute inflammation in the treatment of acne. As a result, transcriptome microarrays analysis of severe acne patients showed that ALA-PDT significantly up-regulated expression of various inflammation-related genes, especially TREM1 and PTGS2, which were further confirmed by a C.acnes induced acne-like mouse ear model. The subsequent experiments demonstrated that ALA-PDT could trigger pro-inflammatory M1 polarization of macrophages in vitro and in vivo. Additionally, the crosstalk between keratinocytes and macrophages studied by a transwell co-culture system indicated that PGE2 secreted by ALA-PDT treated HaCaT cells could promote THP-1 macrophages M1 polarization by COX2/PGE2/TLR4/TREM1 axis to augment inflammation. Our study provides a novel insight that ALA-PDT could amplify inflammation by COX2/TREM1 mediated macrophages M1 polarization for the treatment of acne. It is hoped that this research will decipher the mechanism of ALA-PDT for the treatment of acne and provide a theoretical basis for optimizing the clinical ALA-PDT management.

Condylomata acuminata (CA) is caused by human papillomavirus (HPV). It is one of the most common sexually transmitted diseases (STD). The lesions mainly occur in the external genitalia and perianal areas, rarely involves in urethral and usually localized at the distal 3 cm of the urethral orifice. Because of the special anatomical site, treating urethral CA is challenging and it has high recurrence rate after treatment. 5-aminolevulinic acid photodynamic therapy (ALA-PDT) can successfully treat urethral CA, however, the experience of using ALA-PDT combined with wart curettage to treat intractable urethral CA is still very limited. In here, we reported an intractable urethral CA case with effective remission after receiving combination therapy. Wart curettage combine with ALA-PDT is an expeditious, economical, and well-tolerated treatment method.