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1.
J Cell Biochem ; 125(2): e30503, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-37992185

RESUMEN

Antimicrobial resistance (AMR) is a silent pandemic declared by the WHO that requires urgent attention in the post-COVID world. AMR is a critical public health concern worldwide, potentially affecting people at different stages of life, including the veterinary and agriculture industries. Notably, very few new-age antimicrobial agents are in the current developmental pipeline. Thus, the design, discovery, and development of new antimicrobial agents are required to address the menace of AMR. Antimicrobial peptides (AMPs) are an important class of antimicrobial agents for combating AMR due to their broad-spectrum activity and ability to evade AMR through a multimodal mechanism of action. However, molecular size, aggregability, proteolytic degradation, cytotoxicity, and hemolysis activity significantly limit the clinical application of natural AMPs. The de novo design and engineering of a short synthetic amphipathic AMP (≤16 aa, Mol. Wt. ≤ 2 kDa) with an unusual architecture comprised of coded and noncoded amino acids (NCAAs) is presented here, which demonstrates potent antibacterial activity against a few selected bacterial strains mentioned in the WHO priority list. The designer AMP is conformationally ordered in solution and effectively permeabilizes the outer and inner membranes, leading to bacterial growth inhibition and death. Additionally, the peptide is resistant to proteolysis and has negligible cytotoxicity and hemolysis activity up to 150 µM toward cultured human cell lines and erythrocytes. The designer AMP is unique and appears to be a potent therapeutic candidate, which can be subsequently subjected to preclinical studies to explicitly understand and address the menace of AMR.


Asunto(s)
Antiinfecciosos , Péptidos Antimicrobianos , Humanos , Péptidos Catiónicos Antimicrobianos/farmacología , Péptidos Catiónicos Antimicrobianos/química , Hemólisis , Antibacterianos/farmacología , Antibacterianos/química , Antiinfecciosos/farmacología
2.
J Cell Biochem ; 124(2): 266-281, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36565188

RESUMEN

The complement system is central to the rapid immune response witnessed in vertebrates and invertebrates, which plays a crucial role in physiology and pathophysiology. Complement activation fuels the proteolytic cascade, which produces several complement fragments that interacts with a distinct set of complement receptors. Among all the complement fragments, C5a is one of the most potent anaphylatoxins, which exerts solid pro-inflammatory responses in a myriad of tissues by binding to the complement receptors such as C5aR1 (CD88, C5aR) and C5aR2 (GPR77, C5L2), which are part of the rhodopsin subfamily of G-protein coupled receptors. In terms of signaling cascade, recruitment of C5aR1 or C5aR2 by C5a triggers the association of either G-proteins or ß-arrestins, providing a protective response under normal physiological conditions and a destructive response under pathophysiological conditions. As a result, both deficiency and unregulated activation of the complement lead to clinical conditions that require therapeutic intervention. Indeed, complement therapeutics targeting either the complement fragments or the complement receptors are being actively pursued by both industry and academia. In this context, the model structural complex of C5a-C5aR1 interactions, followed by a biophysical evaluation of the model complex, has been elaborated on earlier. In addition, through the drug repurposing strategy, we have shown that small molecule drugs such as raloxifene and prednisone may act as neutraligands of C5a by effectively binding to C5a and altering its biologically active molecular conformation. Very recently, structural models illustrating the intermolecular interaction of C5a with C5aR2 have also been elaborated by our group. In the current study, we provide the biophysical validation of the C5a-C5aR2 model complex by recruiting major synthetic peptide fragments of C5aR2 against C5a. In addition, the ability of the selected neutraligands to hinder the interaction of C5a with the peptide fragments derived from both C5aR1 and C5aR2 has also been explored. Overall, the computational and experimental data provided in the current study supports the idea that small molecule drugs targeting C5a can potentially neutralize C5a's ability to interact effectively with its cognate complement receptors, which can be beneficial in modulating the destructive signaling response of C5a under pathological conditions.


Asunto(s)
Receptores de Complemento , Transducción de Señal , Animales , beta-Arrestinas
3.
J Cell Biochem ; 123(11): 1841-1856, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35977039

RESUMEN

The complement fragment C5a is one of the most potent proinflammatory glycoproteins liberated by the activation of the biochemical cascade of the complement system. C5a is established to interact with a set of genomically related transmembrane receptors, like C5aR1 (CD88, C5aR) and C5aR2 (GPR77, C5L2) with comparable affinity. The C5aR1 is a classical G-protein-coupled receptor (GPCR), whereas C5aR2 is a nonclassical GPCR that tailors immune cell activity potentially through ß-arrestins rather than G-proteins. Currently, the exact function of the C5aR2 is actively debated in the context of C5aR1, even though both C5aR1 and C5aR2 are coexpressed on myriads of tissues. The functional relevance of C5aR2 appears to be context-dependent compared to the C5aR1, which has received enormous attention for its role in both acute and chronic inflammatory diseases. In addition, the structure of C5aR2 and its interaction specificity toward C5a is not structurally elucidated in the literature so far. The current study has attempted to close the gap by generating highly refined model structures of C5aR2, respectively in free (inactive), complexed to C-terminal peptide of C5a (meta-active) and the C5a (active), embedded to a model palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer. The computational modeling and the 1.5-µs molecular dynamics data presented in the current study are expected to further enrich the understanding of C5a-C5aR2 interaction compared to C5a-C5aR1, which will surely help in elaborating the currently debated biological function of C5aR2 better in the foreseeable future.


Asunto(s)
Complemento C5a , Genómica , Complemento C5a/genética , Complemento C5a/metabolismo , beta-Arrestinas , Receptor de Anafilatoxina C5a/genética
4.
Mol Cell ; 56(4): 541-50, 2014 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-25306922

RESUMEN

Negamycin (NEG) is a ribosome-targeting antibiotic that exhibits clinically promising activity. Its binding site and mode of action have remained unknown. We solved the structure of the Thermus thermophilus ribosome bound to mRNA and three tRNAs, in complex with NEG. The drug binds to both small and large ribosomal subunits at nine independent sites. Resistance mutations in the 16S rRNA unequivocally identified the binding site in the vicinity of the conserved helix 34 (h34) in the small subunit as the primary site of antibiotic action in the bacterial and, possibly, eukaryotic ribosome. At this site, NEG contacts 16S rRNA as well as the anticodon loop of the A-site tRNA. Although the NEG site of action overlaps with that of tetracycline (TET), the two antibiotics exhibit different activities: while TET sterically hinders binding of aminoacyl-tRNA to the ribosome, NEG stabilizes its binding, thereby inhibiting translocation and stimulating miscoding.


Asunto(s)
Antibacterianos/química , Inhibidores de la Síntesis de la Proteína/química , ARN Bacteriano/química , ARN Ribosómico/química , ARN de Transferencia/química , Secuencias de Aminoácidos , Aminoácidos Diaminos/química , Secuencia de Bases , Sitios de Unión , Cristalografía por Rayos X , Modelos Moleculares , Biosíntesis de Proteínas , Estabilidad del ARN , ARN Mensajero/química , Subunidades Ribosómicas Grandes Bacterianas/química , Subunidades Ribosómicas Pequeñas Bacterianas/química , Thermus thermophilus
5.
Mol Cell ; 52(5): 629-42, 2013 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-24239289

RESUMEN

The expression of many genes is controlled by upstream ORFs (uORFs). Typically, the progression of the ribosome through a regulatory uORF, which depends on the physiological state of the cell, influences the expression of the downstream gene. In the classic mechanism of induction of macrolide resistance genes, antibiotics promote translation arrest within the uORF, and the static ribosome induces a conformational change in mRNA, resulting in the activation of translation of the resistance cistron. We show that ketolide antibiotics, which do not induce ribosome stalling at the uORF of the ermC resistance gene, trigger its expression via a unique mechanism. Ketolides promote frameshifting at the uORF, allowing the translating ribosome to invade the intergenic spacer. The dynamic unfolding of the mRNA structure leads to the activation of resistance. Conceptually similar mechanisms may control other cellular genes. The identified property of ketolides to reduce the fidelity of reading frame maintenance may have medical implications.


Asunto(s)
Sistema de Lectura Ribosómico/efectos de los fármacos , Sistema de Lectura Ribosómico/genética , Regulación de la Expresión Génica/efectos de los fármacos , Macrólidos/farmacología , Ribosomas/efectos de los fármacos , Ribosomas/genética , Secuencia de Aminoácidos , Antibacterianos/farmacología , Secuencia de Bases , Cetólidos/farmacología , Metiltransferasas/genética , Datos de Secuencia Molecular , Sistemas de Lectura Abierta/efectos de los fármacos , Biosíntesis de Proteínas , ARN Mensajero/genética
6.
Pediatr Surg Int ; 37(1): 145-150, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33170363

RESUMEN

PURPOSE: The management of urinary tract calculi has evolved dramatically in children with the development of smaller and more durable endoscopic equipment. The indications for therapeutic ureteroscopy in children have significantly expanded with the availability of smaller caliber endoscopes and Holmium:YAG laser. In this paper, we review our experience of the management of urolithiasis and report outcomes of therapeutic ureterorenoscopy (URS) in children younger than 60 months. METHODS: We retrospectively reviewed the inpatient, outpatient records, and imaging data of our hospital, of all children ≤ 60 months of age undergoing URS for the treatment of urinary stones. RESULTS: During the study period; 77 children, mostly male (70.1%) presenting with a single calculus and a mean age of 28.97 ± 2.44 months underwent therapeutic URS. A majority of children (71.4%) had lower or mid-ureteric calculi. Pre URS double J (DJ) stenting was necessary for 21 (27.2%) children. A total of 24 (31.1%) children needed ureteric dilatation before the ureteroscopy. Post URS DJ stenting was necessary in 41 (53.2%) children. Stents were retrieved within 10 days of the procedure. Stone clearance rate following a single-stage URS procedure was 94.8%, and 4 (5.2%) children needed additional shockwave lithotripsy (SWL) to achieve stone clearance. Overall complication rate including hematuria and fever was 12.9% (10 patients). CONCLUSION: Therapeutic ureterorenoscopy in the management of ureteric and selective renal pelvic calculi is safe and effective. It can be considered as the first-line therapy in young children.


Asunto(s)
Ureteroscopía/métodos , Urolitiasis/terapia , Preescolar , Femenino , Humanos , Masculino , Estudios Retrospectivos , Stents , Resultado del Tratamiento
7.
J Biol Chem ; 292(42): 17290-17301, 2017 10 20.
Artículo en Inglés | MEDLINE | ID: mdl-28842504

RESUMEN

Clostridium difficile is a major nosocomial pathogen that produces two exotoxins, TcdA and TcdB, with TcdB thought to be the primary determinant in human disease. TcdA and TcdB are large, multidomain proteins, each harboring a cytotoxic glucosyltransferase domain that is delivered into the cytosol from endosomes via a translocation domain after receptor-mediated endocytosis of toxins from the cell surface. Although there are currently no known host cell receptors for TcdA, three cell-surface receptors for TcdB have been identified: CSPG4, NECTIN3, and FZD1/2/7. The sites on TcdB that mediate binding to each receptor are not defined. Furthermore, it is not known whether the combined repetitive oligopeptide (CROP) domain is involved in or required for receptor binding. Here, in a screen designed to identify sites in TcdB that are essential for target cell intoxication, we identified a region at the junction of the translocation and the CROP domains that is implicated in CSPG4 binding. Using a series of C-terminal truncations, we show that the CSPG4-binding site on TcdB extends into the CROP domain, requiring three short repeats for binding and for full toxicity on CSPG4-expressing cells. Consistent with the location of the CSPG4-binding site on TcdB, we show that the anti-TcdB antibody bezlotoxumab, which binds partially within the first three short repeats, prevents CSPG4 binding to TcdB. In addition to establishing the binding region for CSPG4, this work ascribes for the first time a role in TcdB CROPs in receptor binding and further clarifies the relative roles of host receptors in TcdB pathogenesis.


Asunto(s)
Proteínas Bacterianas/metabolismo , Toxinas Bacterianas/metabolismo , Proteoglicanos Tipo Condroitín Sulfato/metabolismo , Clostridioides difficile/enzimología , Glucosiltransferasas/metabolismo , Proteínas de la Membrana/metabolismo , Animales , Anticuerpos Monoclonales/química , Anticuerpos Neutralizantes/química , Proteínas Bacterianas/antagonistas & inhibidores , Proteínas Bacterianas/genética , Toxinas Bacterianas/antagonistas & inhibidores , Toxinas Bacterianas/genética , Anticuerpos ampliamente neutralizantes , Células CHO , Células CACO-2 , Chlorocebus aethiops , Proteoglicanos Tipo Condroitín Sulfato/genética , Clostridioides difficile/genética , Clostridioides difficile/patogenicidad , Cricetinae , Cricetulus , Glucosiltransferasas/antagonistas & inhibidores , Glucosiltransferasas/genética , Células HEK293 , Humanos , Proteínas de la Membrana/genética , Unión Proteica , Dominios Proteicos
8.
Nat Chem Biol ; 12(3): 153-8, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26727240

RESUMEN

Regulation of gene expression in response to the changing environment is critical for cell survival. For instance, binding of macrolide antibiotics to the ribosome promotes translation arrest at the leader open reading frames ermCL and ermBL, which is necessary for inducing the antibiotic resistance genes ermC and ermB. Cladinose-containing macrolides such as erythromycin (ERY), but not ketolides such as telithromycin (TEL), arrest translation of ermCL, whereas either ERY or TEL stall ermBL translation. How the ribosome distinguishes between chemically similar small molecules is unknown. We show that single amino acid changes in the leader peptide switch the specificity of recognition of distinct molecules, triggering gene activation in response to ERY alone, to TEL alone or to both antibiotics or preventing stalling altogether. Thus, the ribosomal response to chemical signals can be modulated by minute changes in the nascent peptide, suggesting that protein sequences could have been optimized for rendering translation sensitive to environmental cues.


Asunto(s)
Péptidos/genética , Ribosomas/genética , Aminoácidos/química , Antibacterianos/farmacología , Eritromicina/farmacología , Regulación de la Expresión Génica/genética , Hexosas/química , Cetólidos/farmacología , Metiltransferasas/genética , Péptidos/metabolismo , Biosíntesis de Proteínas/genética , Ribosomas/metabolismo , Especificidad por Sustrato , Activación Transcripcional/genética
9.
J Biomol Struct Dyn ; : 1-16, 2024 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-38247266

RESUMEN

The complement component fragment 5a (C5a) binds and activates two complement receptors like C5aR1 and C5aR2, which play a significant role in orchestrating the proinflammatory function of C5a in tissues through the recruitment of heterotrimeric G-proteins and ß-arrestins. Dysregulation of the complement induces excessive production of C5a, which triggers aberrant activation of the C5a-C5aR1-G-protein and C5a-C5aR2-ß-arrestin signalling axes in tissues, contributing to the pathology of numerous immune-inflammatory diseases. Thus, understanding the interaction of C5a with C5aR1 and C5aR2, as well as the interaction of G-protein and ß-arrestins, respectively, with C5a-C5aR1 and C5a-C5aR2, holds tremendous therapeutic value. In the absence of structural data, we have previously elaborated the binary complexes of C5a-C5aR1 and C5a-C5aR2, as well as the ternary complex of C5a-C5aR2-ß-arrestin1, in highly refined model structures. While our ternary model complex of C5a-C5aR1-G-protein was in progress, two cryo-electron microscopy-based ternary structural complexes of C5aR1 were made available by others. However, it is observed that the interaction of the crucial NT-peptide of C5aR1 with C5a, including the portion of the G⍺i-subunit that harbors the switch-I region, is not fully resolved in both complexes. The current study addresses the issues and provides two highly refined alternative model ternary complexes of C5a-C5aR1-G-protein. The study highlights the conformational heterogeneity in C5aR1 by comparing the two conformational variants of the model ternary complex in the context of C5a-C5aR2-ß-arrestin1 for further devising methods and molecules targeting both surface and intracellular C5aR1/C5aR2 for effectively mitigating the proinflammatory role of C5a in various disease settings.Communicated by Ramaswamy H. Sarma.

10.
J Pharm Bioallied Sci ; 16(Suppl 3): S2100-S2102, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39346270

RESUMEN

Background: To determine the amount of apical extrusion between various file systems during the retreatment procedure and to determine the effect of taper on the same. Materials and Method: Seventy mandibular extracted premolars were taken, and preparation was performed using a Woodpecker file (Woodpecker Medical Instrument Co., Ltd., Guilin, China) (25/0.06). The gutta-percha (GP) was removed from each specimen with H file (#40/0.02) to simulate retreatment in seven groups (n = 10) using ProTaper Next (PTN;Dentsply, Maillefer, Ballaigues, Switzerland) (PTN) (30/0.07), Reciproc (25/0.08), Hyflex CM (30/0.06), Mtwo (30/0.05), Neoendo flex (30/0.04), Neoendo hybrid (30/0.04), and Flexicon file (30/0.06). The specimens were held with the help of a rubber stopper and put in the Eppendorf tube of volume 4 mL (pre-weighed before retreatment). The debris that was on the root surface of the specimen was washed with distilled water with 1 mL volume, kept in the oven, and then again weighed after 7 days. Results: Apical extrusion was found in the following order: HYFLEX CM (LEAST) < FLEXICON < PROTAPER NEXT < RECIPROC < NEOENDO FLEX < NEOENDO HYBRID < MTWO (HIGHEST). Conclusion: W Hyflex CM and Flexicon files showed lesser extrusion of debris than others.

11.
J Conserv Dent Endod ; 27(8): 811-816, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39372578

RESUMEN

Aim and Objectives: The study aimed to evaluate and compare the effect of various beverages carbonated drinks, i.e., thumps up, fresh fruit juice (apple and pomegranate) and packaged fruit juice (apple and pomegranate) on tooth surface morphology under scanning electron microscope. Materials and Methods: Thirty recently extracted intact caries-free human permanent teeth were disinfected with 5.25% of sodium hypochlorite solution and autoclaved at 240°F, 20 psi pressure for 40 min. Each tooth was sectioned into 4 enamel sections yielding 120 sections which were embedded in resin using a prefabricated mold. Prepared samples were immersed as Group I - thumps up, Group II - fresh apple juice, Group III - packaged apple juice, Group IV - fresh pomegranate juice, Group V - packaged pomegranate juice, and Group VI - normal saline. Each immersion was done daily for 30 min over 14 days after which samples were scanned under scanning electron microscope (SEM). The data obtained were subjected to statistical analysis using Statistical Package for the Social Sciences (SPSS Version 23; Chicago Inc., IL, USA). Results: The highest surface roughness was noted in the fresh pomegranate and packaged pomegranate groups with a mean of 2.9000 ± 0.30779 followed by thumbs up group. The greatest mean of cracks was noted in thumbs up group with a mean of 2.500 ± 0.51299 which was significant at P = 0.000. The greatest mean of score was noted in thumbs up group with a mean of 2.3000 ± 0.65695 which was significant at P = 0.000. Conclusion: The present study demonstrated that all drinks were erosive in nature with thumps and pomegranate juice showing significantly higher erosiveness than apple juice (P < 0.01).

12.
J Med Chem ; 67(16): 14110-14124, 2024 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-39051153

RESUMEN

C5a is an integral glycoprotein of the complement system that plays an important role in inflammation and immunity. The physiological concentration of C5a is observed to be elevated under various immunoinflammatory pathophysiological conditions in humans. The pathophysiology of C5a is linked to the "two-site" protein-protein interactions (PPIs) with two genomically related receptors, such as C5aR1 and C5aR2. Therefore, pharmacophores that can potentially block the PPIs between C5a-C5aR1 and C5a-C5aR2 have tremendous potential for development as future therapeutics. Notably, the FDA has already approved antibodies that target the precursors of C5a (Eculizumab, 148 kDa) and C5a (Vilobelimab, 149 kDa) for marketing as complement-targeted therapeutics. In this context, the current study reports the structural characterization of a pair of synthetic designer antibody-like peptides (DePA and DePA1; ≤3.8 kDa) that bind to hotspot regions on C5a and also demonstrates potential traits to neutralize the function of C5a under pathophysiological conditions.


Asunto(s)
Complemento C5a , Péptidos , Receptor de Anafilatoxina C5a , Transducción de Señal , Humanos , Receptor de Anafilatoxina C5a/metabolismo , Receptor de Anafilatoxina C5a/química , Receptor de Anafilatoxina C5a/antagonistas & inhibidores , Complemento C5a/metabolismo , Complemento C5a/química , Péptidos/química , Péptidos/farmacología , Péptidos/metabolismo , Transducción de Señal/efectos de los fármacos , Unión Proteica , Anticuerpos/química , Anticuerpos/metabolismo , Anticuerpos/inmunología , Diseño de Fármacos
13.
J Phys Chem B ; 128(19): 4631-4645, 2024 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-38657271

RESUMEN

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a novel coronavirus, is the causative agent responsible for the spread of the COVID19 pandemic across the globe. The global impact of the COVID19 pandemic, the successful approval of vaccines for controlling the pandemic, and the further resurgence of COVID19 necessitate the exploration and validation of alternative therapeutic avenues targeting SARS-CoV-2. The initial entry and further invasion by SARS-CoV-2 require strong protein-protein interactions (PPIs) between the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein and the human angiotensin-converting enzyme 2 (ACE2) receptors expressed on the cell surfaces of various tissues. In principle, disruption of the PPIs between the RBD of SARS-CoV-2 and the ACE2 receptor by designer peptides with optimized pharmacology appears to be an ideal choice for potentially preventing viral entry with minimal immunogenicity. In this context, the current study describes a short, synthetic designer peptide (codenamed SR16, ≤18 aa, molecular weight ≤2.5 kDa), which has a few noncoded amino acids, demonstrates a helical conformation in solution, and also engages the RBD of SARS-CoV-2 through a high-affinity interaction, as judged from a battery of biophysical studies. Further, the designer peptide demonstrates resistance to trypsin degradation, appears to be nontoxic to mammalian cells, and also does not induce hemolysis in freshly isolated human erythrocytes. In summary, SR16 appears to be an ideal peptide binder targeting the RBD of SARS-CoV-2, which has the potential for further optimization and development as an antiviral agent targeting SARS-CoV-2.


Asunto(s)
Enzima Convertidora de Angiotensina 2 , Antivirales , Péptidos , Unión Proteica , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , Humanos , SARS-CoV-2/efectos de los fármacos , Glicoproteína de la Espiga del Coronavirus/metabolismo , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/antagonistas & inhibidores , Antivirales/química , Antivirales/farmacología , Enzima Convertidora de Angiotensina 2/metabolismo , Enzima Convertidora de Angiotensina 2/química , Péptidos/química , Péptidos/farmacología , Péptidos/síntesis química , Dominios Proteicos , Sitios de Unión , Diseño de Fármacos , COVID-19/virología , Tratamiento Farmacológico de COVID-19
14.
J Biomol Struct Dyn ; : 1-17, 2023 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-37493401

RESUMEN

Complement component fragment 5a (C5a) is one of the potent proinflammatory modulators of the complement system. C5a recruits two genomically related G protein-coupled receptors (GPCRs), like C5aR1 and C5aR2, constituting a binary complex. The C5a-C5aR1/C5aR2 binary complexes involve other transducer proteins like heterotrimeric G-proteins and ß-arrestins to generate the fully active ternary complexes that trigger intracellular signaling through downstream effector molecules in tissues. In the absence of structural data, we had recently developed highly refined model structures of C5aR2 in its inactive (free), meta-active (complexed to the CT-peptide of C5a), and active (complexed to C5a) state embedded to a model palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer. Compared to C5aR1, C5aR2 is established as a noncanonical GPCR, as it recruits and signals through ß-arrestins rather than G-proteins. Notably, structural understanding of the ternary complex involving C5a-C5aR2-ß-arrestin is currently unknown. The current study has attempted to fill the gap by generating a highly refined, fully active ternary model structural complex of the C5a-C5aR2-ß-arrestin1 embedded in a model POPC bilayer. The computational modeling, 500 ns molecular dynamics (MD) studies, and the principal component analysis (PCA), including the molecular mechanics Poisson-Boltzmann surface area (MM PBSA) based data presented in this study, provide an experimentally testable hypothesis about C5a-C5aR2-ß-arrestin1 extendable to other such ternary systems. The model ternary complex of C5a-C5aR2-ß-arrestin1 will further enrich the current structural understanding related to the interaction of ß-arrestins with the C5a-C5aR2 system.Communicated by Ramaswamy H. Sarma.

15.
Indian J Otolaryngol Head Neck Surg ; 75(3): 2328-2333, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37636644

RESUMEN

Larynx is an uncommon extranodal site for non-Hodgkin lymphoma (NHL). Anaplastic lymphoma kinase (ALK)-positive B-cell lymphoma is a rare and aggressive form of NHL. A 19-year-old male presented to the ENT department with globus sensation, hoarseness, cervical lymphadenopathy and weight loss. A 70-degree rigid endoscopic examination of the larynx showed a vascular, irregular, submucosal mass arising from the right aryepiglottic fold causing near complete obstruction of the laryngeal airway. PET-CT showed hypermetabolic lesions in the supraglottis, cervical lymph nodes, cervical spine, ribs and abdominal lymph nodes. Biopsy was taken from the supraglottic mass as well as the enlarged cervical lymph nodes, which revealed ALK-positive large B-cell NHL. In this report, we present a rare case of ALK-positive large B-cell NHL of the larynx, discussing its clinical, radiological and pathological features. A limited review of literature is also presented. There is a need to develop a database for the description of lymphomas affecting the larynx and this case report adds to the existing knowledge of this rare entity.

16.
Front Oncol ; 12: 1000106, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36185202

RESUMEN

Multiple myeloma (MM) is a plasma cell dyscrasia characterized by the clonal proliferation of antibody producing plasma cells. Despite the use of next generation proteasome inhibitors (PI), immunomodulatory agents (IMiDs) and immunotherapy, the development of therapy refractory disease is common, with approximately 20% of MM patients succumbing to aggressive treatment-refractory disease within 2 years of diagnosis. A large emphasis is placed on understanding inter/intra-tumoral genetic, epigenetic and transcriptomic changes contributing to relapsed/refractory disease, however, the contribution of cellular metabolism and intrinsic/extrinsic metabolites to therapy sensitivity and resistance mechanisms is less well understood. Cancer cells depend on specific metabolites for bioenergetics, duplication of biomass and redox homeostasis for growth, proliferation, and survival. Cancer therapy, importantly, largely relies on targeting cellular growth, proliferation, and survival. Thus, understanding the metabolic changes intersecting with a drug's mechanism of action can inform us of methods to elicit deeper responses and prevent acquired resistance. Knowledge of the Warburg effect and elevated aerobic glycolysis in cancer cells, including MM, has allowed us to capitalize on this phenomenon for diagnostics and prognostics. The demonstration that mitochondria play critical roles in cancer development, progression, and therapy sensitivity despite the inherent preference of cancer cells to engage aerobic glycolysis has re-invigorated deeper inquiry into how mitochondrial metabolism regulates tumor biology and therapy efficacy. Mitochondria are the sole source for coupled respiration mediated ATP synthesis and a key source for the anabolic synthesis of amino acids and reducing equivalents. Beyond their core metabolic activities, mitochondria facilitate apoptotic cell death, impact the activation of the cytosolic integrated response to stress, and through nuclear and cytosolic retrograde crosstalk maintain cell fitness and survival. Here, we hope to shed light on key mitochondrial functions that shape MM development and therapy sensitivity.

17.
Sci Adv ; 8(39): eabq5575, 2022 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-36170375

RESUMEN

The connections between metabolic state and therapy resistance in multiple myeloma (MM) are poorly understood. We previously reported that electron transport chain (ETC) suppression promotes sensitivity to the BCL-2 antagonist venetoclax. Here, we show that ETC suppression promotes resistance to proteasome inhibitors (PIs). Interrogation of ETC-suppressed MM reveals integrated stress response-dependent suppression of protein translation and ubiquitination, leading to PI resistance. ETC and protein translation gene expression signatures from the CoMMpass trial are down-regulated in patients with poor outcome and relapse, corroborating our in vitro findings. ETC-suppressed MM exhibits up-regulation of the cystine-glutamate antiporter SLC7A11, and analysis of patient single-cell RNA-seq shows that clusters with low ETC gene expression correlate with higher SLC7A11 expression. Furthermore, erastin or venetoclax treatment diminishes mitochondrial stress-induced PI resistance. In sum, our work demonstrates that mitochondrial stress promotes PI resistance and underscores the need for implementing combinatorial regimens in MM cognizant of mitochondrial metabolic state.


Asunto(s)
Mieloma Múltiple , Inhibidores de Proteasoma , Antiportadores , Compuestos Bicíclicos Heterocíclicos con Puentes , Línea Celular Tumoral , Cistina/metabolismo , Cistina/uso terapéutico , Glutamatos , Humanos , Mieloma Múltiple/tratamiento farmacológico , Mieloma Múltiple/genética , Mieloma Múltiple/metabolismo , Inhibidores de Proteasoma/farmacología , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Sulfonamidas
18.
Indian J Surg Oncol ; 12(1): 229-234, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33814858

RESUMEN

Cancer of the penis is an important health problem in India, causing significant morbidity. Involvement of locoregional lymph nodes is the most significant prognostic factor for patients with penile cancer. In this study, we reviewed clinical data of all patients who underwent modified inguinal lymph node dissection as a means to diagnose micro-metastasis in inguinal lymph nodes, and analysed the outcomes. We retrospectively reviewed the hospital clinical charts of patients treated for carcinoma of the penis. Inguinal and distant metastases were assessed by physical examination, ultrasound imaging of the inguinal region, computed tomography of the abdomen and pelvis and a chest radiograph. Patients with clinically negative inguinal lymph nodes underwent modified lymph node dissection (mILND) both to diagnose and stage the disease. Complications occurring during a 30-day period after surgery were defined as early and thereafter as late complications. A total of 40 patients with a mean age of 52.27±13.10 (range 25-73) years underwent mILND. Wedge biopsy from the primary lesion had revealed intermediate-risk disease in 22 (55%) patients and high-risk disease in 18 (45%) patients. Histopathological examination of the primary penile lesion revealed a pT1 lesion in 32 patients and a pT2 lesion in the remaining 8 patients. Fourteen (35%) of the 40 patients showed micro-metastases in the inguinal lymph nodes on frozen sections. The mean follow-up in these patients was 56.6±18.09 months. There were no instances of local or systemic recurrences seen in 38 (95%) patients within 5 years. Superficial lymph node dissection and where facilities are available DSLNB remain the standard of care in the management of patients with clinically groin-negative (cN0) intermediate- and high-risk groups. Modified inguinal lymph node dissection would be a safe and appropriate alternative to this in all centres that do not have access to newer modalities like DSLNB, video-endoscopic (VEIL) or robotic-assisted techniques.

19.
J Family Med Prim Care ; 9(6): 2958-2962, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32984155

RESUMEN

BACKGROUND: Evidence-based practice is the cornerstone of dentistry and especially endodontics. Diagnosis, treatment planning, and treatment with recent advancement based on evidence would be a great help for the patent satisfaction and treatment prognosis; hence, the aim of present study was to explore difference between perception, knowledge, and practice of endodontists and general dental practitioners (GDPs) towards evidence-based practice and factors associated with it. MATERIALS AND METHODS: The present study is a cross-sectional descriptive questionnaire study conducted among specialists in the subject of conservative and endodontic dentistry and GDPs working in private clinics in Modinagar city, Uttar Pradesh. The study was conducted in October 2019. In the present study, a close-ended questionnaire was prepared to determine the perception and practice of dental specialists. RESULTS: The majority of endodontists (31 [35.22%]) belonged to the age group of 36-45 years of age while most of the GDPs (32 [36.36%]) belonged to 25-35 years of age group. The majority of endodontists were females (56[63.64%]) and most of the GDPs were males (50 (56.81]). More endodontists (47 [53.42]) had a positive perception of evidence-based practice than GDPs (15[16.42]). Practice toward evidence was fair among most of the endodontists (49 [55.68%]) and GDPs (54 [61.36%]). CONCLUSION: There was a more positive perception regarding evidence-based practice among endodontists than GDPs, knowledge was high among endodontists regarding evidence-based practice and practice was also good among endodontists. Factors associated with perception, knowledge, and practice among endodontists and GDPs were age in years, gender, year of practice, number of endodontic patients treating per month.

20.
J Family Med Prim Care ; 9(1): 282-286, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32110605

RESUMEN

BACKGROUND: Choosing latest technology for the treatment improves the chances of favorable prognosis and saves the time of the clinician; hence, the aim of the study was to explore their knowledge, attitude, and practice (KAP) toward following proper standards of endodontic practice and use of latest technology. MATERIALS AND METHODS: The present study was a cross-sectional, descriptive questionnaire study conducted among general dental practitioners (GDPs). The survey was conducted among 156 GDPs. In the present study, a close-ended interview schedule was prepared to test the KAP of GDPs. RESULTS: For diagnosis, most of the study participants (58 [37.08%]) relied on case history and radiograph. Apex locator was used by 71 (45.51%) of the study subjects. Among all the study participants, 58 (37.17%) dental practitioners used rotary nickel-titanium (NiTi) files with normal saline and preheated disinfectants for cleaning and shaping of root canal. It was observed that the knowledge of majority of the dental practitioners was fair (58 [37.17%]). However, the attitude and practice toward following proper standards of endodontic practice and use of latest technology were poor. CONCLUSION: It was concluded that very few general practitioners used the latest technology in endodontics. Knowledge was fair while attitude and practice regarding following proper standards of endodontic practice and use of latest technology were poor among study participants.

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