Genetic mechanism regulating diversity in the placement of eyes on the head of animals.

Despite the conservation of genetic machinery involved in eye development, there is a strong diversity in the placement of eyes on the head of animals. Morphogen gradients of signaling molecules are vital to patterning cues. During Drosophila eye development, Wingless (Wg), a ligand of Wnt/Wg signaling, is expressed anterolaterally to form a morphogen gradient to determine the eye- versus head-specific cell fate. The underlying mechanisms that regulate this process are yet to be fully understood. We characterized defective proventriculus (dve) (Drosophila ortholog of human SATB1), a K50 homeodomain transcription factor, as a dorsal eye gene, which regulates Wg signaling to determine eye versus head fate. Across Drosophila species, Dve is expressed in the dorsal head vertex region where it regulates wg transcription. Second, Dve suppresses eye fate by down-regulating retinal determination genes. Third, the dve-expressing dorsal head vertex region is important for Wg-mediated inhibition of retinal cell fate, as eliminating the Dve-expressing cells or preventing Wg transport from these dve-expressing cells leads to a dramatic expansion of the eye field. Together, these findings suggest that Dve regulates Wg expression in the dorsal head vertex, which is critical for determining eye versus head fate. Gain-of-function of SATB1 exhibits an eye fate suppression phenotype similar to Dve. Our data demonstrate a conserved role for Dve/SATB1 in the positioning of eyes on the head and the interocular distance by regulating Wg. This study provides evidence that dysregulation of the Wg morphogen gradient results in developmental defects such as hypertelorism in humans where disproportionate interocular distance and facial anomalies are reported.

Inactivation of Hippo and cJun-N-terminal Kinase (JNK) signaling mitigate FUS mediated neurodegeneration in vivo.

Amyotrophic Lateral Sclerosis (ALS), a late-onset neurodegenerative disorder characterized by the loss of motor neurons in the central nervous system, has no known cure to-date. Disease causing mutations in human Fused in Sarcoma (FUS) leads to aggressive and juvenile onset of ALS. FUS is a well-conserved protein across different species, which plays a crucial role in regulating different aspects of RNA metabolism. Targeted misexpression of FUS in Drosophila model recapitulates several interesting phenotypes relevant to ALS including cytoplasmic mislocalization, defects at the neuromuscular junction and motor dysfunction. We screened for the genetic modifiers of human FUS-mediated neurodegenerative phenotype using molecularly defined deficiencies. We identified hippo (hpo), a component of the evolutionarily conserved Hippo growth regulatory pathway, as a genetic modifier of FUS mediated neurodegeneration. Gain-of-function of hpo triggers cell death whereas its loss-of-function promotes cell proliferation. Downregulation of the Hippo signaling pathway, using mutants of Hippo signaling, exhibit rescue of FUS-mediated neurodegeneration in the Drosophila eye, as evident from reduction in the number of TUNEL positive nuclei as well as rescue of axonal targeting from the retina to the brain. The Hippo pathway activates c-Jun amino-terminal (NH2) Kinase (JNK) mediated cell death. We found that downregulation of JNK signaling is sufficient to rescue FUS-mediated neurodegeneration in the Drosophila eye. Our study elucidates that Hippo signaling and JNK signaling are activated in response to FUS accumulation to induce neurodegeneration. These studies will shed light on the genetic mechanism involved in neurodegeneration observed in ALS and other associated disorders.

RNA Sequencing Identifies a Common Physiology in Vancomycin- and Ciprofloxacin-Tolerant Staphylococcus aureus Induced by ileS Mutations.

Little is known about the mechanisms by which ileS mutations induce vancomycin tolerance in Staphylococcus aureus This study showed that transcriptome profiles were similar in vancomycin-tolerant mutants and the IleRS-inhibitor-treated parent. Notably, ileS and relA, which induce a stringent response, were upregulated. The same mechanism was responsible for cross-tolerance to vancomycin and ciprofloxacin. These findings suggest that the accumulation of uncharged isoleucyl-tRNA following ileS mutations in S. aureus was responsible for drug tolerance.

Prevalence and antibiogram of coagulase negative Staphylococci in bioaerosols from different indoors of a university in India.

BACKGROUND: Staphylococci species are the major constituents of infectious bioaerosols, particularly methicillin-resistant Staphylococci (MRS) have serious health impacts. Here, the bacterial burden was quantified, especially prevalence of MRS in bioaerosols collected from indoors of Dr. B.R. Ambedkar Central Library (DBRACL) and Central Laboratory Animal Resources (CLAR) of Jawaharlal Nehru University, New Delhi, India. Air samplings from DBRACL and CLAR were done using the settle plate method and SKC biosampler, respectively. RESULTS: This study showed a maximum 6757 CFU/m2/hr of bacterial load in the DBRACL reading room, while unacceptable bacterial loads (> 1000 CFU/m3 of air) at different sites of CLAR. Further, at both the sampling sites the predominance of coagulase negative Staphylococci (CNS) was observed. A total 22 and 35 Staphylococci isolates were isolated from DBRACL and CLAR bioaerosols, respectively. Majority (16/22) of the Staphylococcal isolates from DBRACL belonged to human-associated Staphylococci where S. haemolyticus (5/22) was the most dominating species. However, in CLAR facility centre, animal-associated Staphylococci (19/35) were dominating, where S. xylosus (12/35) was the most dominating species. Further, antibiotic sensitivity tests revealed 41% MRS and 73% multidrug resistant (MDR) among airborne Staphylococci from DBRACL indoor bioaerosols. Similarly, in CLAR facility, approximately, 66% Staphylococci isolates were methicillin resistant, out of which 2 isolates showed high MIC value ≥ 16 µg/mL. Further, we confirmed the presence of 49% multidrug resistant Staphylococci in the indoor air of CLAR facility. CONCLUSIONS: This study suggested that the exposure of workers and students in CLAR to such a high concentration of drug-resistant Staphylococci should not be undermined, as these bacterial concentrations are the direct representative of inhalable particulate matter (PM2.5) as per collection procedure. Simultaneously, passive sampling from DBRACL assessed the risks due to microbial contamination in particle agglomerates, which may deposit on the crucial surfaces such as wounds/ cuts or on the frequently used items.

Genetic and Transcriptomic Analyses of Ciprofloxacin-Tolerant Staphylococcus aureus Isolated by the Replica Plating Tolerance Isolation System (REPTIS).

We developed a simple, efficient, and cost-effective method, named the replica plating tolerance isolation system (REPTIS), to detect the antibiotic tolerance potential of a bacterial strain. This method can also be used to quantify the antibiotic-tolerant subpopulation in a susceptible population. Using REPTIS, we isolated ciprofloxacin (CPFX)-tolerant mutants (mutants R2, R3, R5, and R6) carrying a total of 12 mutations in 12 different genes from methicillin-sensitive Staphylococcus aureus (MSSA) strain FDA209P. Each mutant carried multiple mutations, while few strains shared the same mutation. The R2 strain carried a nonsense mutation in the stress-mediating gene, relA Additionally, two strains carried the same point mutation in the leuS gene, encoding leucyl-tRNA synthetase. Furthermore, RNA sequencing of the R strains showed a common upregulation of relA Overall, transcriptome analysis showed downregulation of genes related to translation; carbohydrate, fat, and energy metabolism; nucleotide synthesis; and upregulation of amino acid biosynthesis and transportation genes in R2, R3, and R6, similar to the findings observed for the FDA209P strain treated with mupirocin (MUP0.03). However, R5 showed a unique transcription pattern that differed from that of MUP0.03. REPTIS is a unique and convenient method for quantifying the level of tolerance of a clinical isolate. Genomic and transcriptomic analyses of R strains demonstrated that CPFX tolerance in these S. aureus mutants occurs via at least two distinct mechanisms, one of which is similar to that which occurs with mupirocin treatment.

The Hippo pathway effector Yki downregulates Wg signaling to promote retinal differentiation in the Drosophila eye.

The evolutionarily conserved Hippo signaling pathway is known to regulate cell proliferation and maintain tissue homeostasis during development. We found that activation of Yorkie (Yki), the effector of the Hippo signaling pathway, causes separable effects on growth and differentiation of the Drosophila eye. We present evidence supporting a role for Yki in suppressing eye fate by downregulation of the core retinal determination genes. Other upstream regulators of the Hippo pathway mediate this effect of Yki on retinal differentiation. Here, we show that, in the developing eye, Yki can prevent retinal differentiation by blocking morphogenetic furrow (MF) progression and R8 specification. The inhibition of MF progression is due to ectopic induction of Wingless (Wg) signaling and Homothorax (Hth), the negative regulators of eye development. Modulating Wg signaling can modify Yki-mediated suppression of eye fate. Furthermore, ectopic Hth induction due to Yki activation in the eye is dependent on Wg. Last, using Cut (Ct), a marker for the antennal fate, we show that suppression of eye fate by hyperactivation of yki does not change the cell fate (from eye to antenna-specific fate). In summary, we provide the genetic mechanism by which yki plays a role in cell fate specification and differentiation - a novel aspect of Yki function that is emerging from multiple model organisms.

In Vitro Tolerance of Drug-Naive Staphylococcus aureus Strain FDA209P to Vancomycin.

The mechanisms underlying bacterial tolerance to antibiotics are unclear. A possible adaptation strategy was explored by exposure of drug-naive methicillin-susceptible Staphylococcus aureus strain FDA209P to vancomycin in vitro Strains surviving vancomycin treatment (vancomycin survivor strains), which appeared after 96 h of exposure, were slow-growing derivatives of the parent strain. Although the vancomycin MICs for the survivor strains were within the susceptible range, the cytokilling effects of vancomycin at 20-fold the MIC were significantly lower for the survivor strains than for the parent strain. Whole-genome sequencing demonstrated that ileS, encoding isoleucyl-tRNA synthetase (IleRS), was mutated in two of the three vancomycin survivor strains. The IleRS Y723H mutation is located close to the isoleucyl-tRNA contact site and potentially affects the affinity of IleRS binding to isoleucyl-tRNA, thereby inhibiting protein synthesis and leading to vancomycin tolerance. Introduction of the mutation encoding IleRS Y723H into FDA209P by allelic replacement successfully transferred the vancomycin tolerance phenotype. We have identified mutation of ileS to be one of the bona fide genetic events leading to the acquisition of vancomycin tolerance in S. aureus, potentially acting via inhibition of the function of IleRS.

Drosophila C-terminal Src kinase regulates growth via the Hippo signaling pathway.

The Hippo signaling pathway is involved in regulating tissue size by inhibiting cell proliferation and promoting apoptosis. Aberrant Hippo pathway function is often detected in human cancers and correlates with poor prognosis. The Drosophila C-terminal Src kinase (d-Csk) is a genetic modifier of warts (wts), a tumor-suppressor gene in the Hippo pathway, and interacts with the Src oncogene. Reduction in d-Csk expression and the consequent activation of Src are frequently seen in several cancers including hepatocellular and colorectal tumors. Previous studies show that d-Csk regulates cell proliferation and tissue size during development. Given the similarity in the loss-of-function phenotypes of d-Csk and wts, we have investigated the interactions of d-Csk with the Hippo pathway. Here we present multiple lines of evidence suggesting that d-Csk regulates growth via the Hippo signaling pathway. We show that loss of dCsk caused increased Yki activity, and our genetic epistasis places dCsk downstream of Dachs. Furthermore, dCsk requires Yki for its growth regulatory functions, suggesting that dCsk is another upstream member of the network of genes that interact to regulate Wts and its effector Yki in the Hippo signaling pathway.

Tumor suppression by cell competition through regulation of the Hippo pathway.

Homeostatic mechanisms can eliminate abnormal cells to prevent diseases such as cancer. However, the underlying mechanisms of this surveillance are poorly understood. Here we investigated how clones of cells mutant for the neoplastic tumor suppressor gene scribble (scrib) are eliminated from Drosophila imaginal discs. When all cells in imaginal discs are mutant for scrib, they hyperactivate the Hippo pathway effector Yorkie (Yki), which drives growth of the discs into large neoplastic masses. Strikingly, when discs also contain normal cells, the scrib(-) cells do not overproliferate and eventually undergo apoptosis through JNK-dependent mechanisms. However, induction of apoptosis does not explain how scrib(-) cells are prevented from overproliferating. We report that cell competition between scrib(-) and wild-type cells prevents hyperproliferation by suppressing Yki activity in scrib(-) cells. Suppressing Yki activation is critical for scrib(-) clone elimination by cell competition, and experimental elevation of Yki activity in scrib(-) cells is sufficient to fuel their neoplastic growth. Thus, cell competition acts as a tumor-suppressing mechanism by regulating the Hippo pathway in scrib(-) cells.

Toxicity and localization studies of a potential photodynamic therapy agent in Drosophila.

Photodynamic therapy utilizes light, a photosensitizer, and molecular oxygen as a treatment modality for a variety of cancers. We have recently combined ruthenium(II) polypyridyl groups with a zinc(II) centered porphyrin as a new photosensitizer for the treatment of melanoma. In-vitro studies have indicated that this photosensitizer is toxic to melanoma cells when irradiated with low energy light; however, it is nontoxic to normal cells under similar conditions. To determine the toxicity and cell viability of this compound in-vivo we present, herein, a study using Drosophila melanogaster. In the absence of light, the new photosensitizer shows no discernible effects to fly larvae at various concentrations of compound and stages of larval development. When the larvae were fed the photosensitizer it was observed, by fluorescence microscopy, that the compound passes through the cell membrane and localizes in the cytosol at lower concentrations and the nucleus at slightly higher concentrations indicating that the compound is not immediately metabolized.

Jejunal calcifying fibrous tumor: A jigsaw puzzle with a pool of diagnostic dilemma.

ABSTRACT: Calcifying fibrous tumor (CFT) is a very rare benign fibroblastic tumor featuring a wide anatomical distribution and mimicking various spindle cell tumors. CFT has been documented in soft tissues, gastrointestinal tract (GIT), neck, adrenal glands, and pleura. Within the GIT, it is reported in the stomach, small bowel, large intestine, stomach, esophagus, and appendix. The occurrence of CFTs in the gastrointestinal tract presents a diagnostic dilemma, firstly due to the rarity of the lesion and secondly, due to the occurrence of a variety of other stromal lesions in the gastrointestinal tract with histological features that overlap with CFT. In the jejunum, it is extremely rare. We present one such rare case of jejunal CFT at an unusual age, complicated by jejuno-jejunal intussusception resulting in acute intestinal obstruction.

Sternoclavicular Tuberculosis: An Unusual Presentation.

Extra pulmonary tuberculosis is on the rise worldwide, and younger patients, are females. And people from Asia and Africa are at high risk. Sternoclavicular TB is extremely rare, even in countries that have a high prevalence of TB. It can be in the absence of pulmonary TB. It has a varied clinical presentation. Painless chest wall swelling can be the presenting symptom of sternoclavicular diagnosis. Ultrasonography and high-resolution computed tomography can identify the nature of the lesion and the extent of bone involvement. Aspiration from the swelling or histopathology examination is mandatory for diagnosis. Caseous necrosis is diagnostic of TB. Detection of acid-fast bacilli in smears or tissue or molecular methods is required for definitive diagnosis. A high degree of clinical suspicion is required for early diagnosis. The treatment of thoracic TB is the subject of controversy. Anti-tubercular drugs are the mainstay of treatment. Surgical intervention is basically for flattening cold abscesses and removing infected tissue, including affected bones and cartilage.

A comparison of the WHO 2004 and WHO 2017 thyroid tumor classifications.

INTRODUCTION: The category of borderline malignancy or unknown malignant potential was added to the WHO's 2017 classification of thyroid tumours. A new histological variety of papillary tumours and Hurthle cell tumours was given as a separate entity. The classification has also adopted the Turin criteria for histological diagnosis of poorly differentiated cancer (PDC). SETTINGS AND DESIGN: Descriptive study. METHODS AND MATERIAL: From July 2018 to June 2022, 200 thyroid neoplasm patients at a tertiary care facility in western Maharashtra were participated in the prospective research over a period of 4 years. STATISTICAL ANALYSIS USED: The descriptive statistics were used to analyse the collected data. AIM: This study was undertaken to compare the old (2004) and new (2016) WHO classifications and their importance in the treatment of thyroid malignancies. RESULTS: Out of 200 cases, the age range of 31 to 40 years had the greatest number of cases. The ratio of females to males was 5:1. In our study, according to the WHO 2004 classification, malignant tumours comprised 57.5% of the cases, while benign tumours 42.5% of the cases. When tumours were subcategorized, the most frequent benign tumour was follicular adenoma (43.5%) and malignant tumour was papillary thyroid carcinoma (37%). Malignant tumours made up 47.5% of the cases when the tumours were reclassified using the revised WHO 2017 classification, followed by borderline tumours with 27.5% of the cases and benign tumours with 25% of the cases. The most frequent borderline tumour was NIFTP (Noninvasive follicular thyroid neoplasm with papillary-like nuclear features) (17.5%), the most prevalent malignant tumour was papillary carcinoma (including its variant) (32%), and the most frequent benign tumour was follicular adenoma (27%). CONCLUSION: We concluded that the inclusion of the Boderline Category in the new WHO classification significantly improved thyroid cancer management. WHO 2017 classification prevents under diagnosis (in the case of benign tumors) and over diagnosis (in the case of malignant tumors).

A Tumor-Specific Molecular Network Promotes Tumor Growth in Drosophila by Enforcing a Jun N-Terminal Kinase-Yorkie Feedforward Loop.

Cancer cells expand rapidly in response to altered intercellular and signaling interactions to achieve the hallmarks of cancer. Impaired cell polarity combined with activated oncogenes is known to promote several hallmarks of cancer, e.g., activating invasion by increased activity of Jun N-terminal kinase (JNK) and sustained proliferative signaling by increased activity of Hippo effector Yorkie (Yki). Thus, JNK, Yki, and their downstream transcription factors have emerged as synergistic drivers of tumor growth through pro-tumor signaling and intercellular interactions like cell competition. However, little is known about the signals that converge onto JNK and Yki in tumor cells and enable tumor cells to achieve the hallmarks of cancer. Here, using mosaic models of cooperative oncogenesis (RasV12,scrib-) in Drosophila, we show that RasV12,scrib- tumor cells grow through the activation of a previously unidentified network comprising Wingless (Wg), Dronc, JNK, and Yki. We show that RasV12,scrib- cells show increased Wg, Dronc, JNK, and Yki signaling, and all these signals are required for the growth of RasV12,scrib- tumors. We report that Wg and Dronc converge onto a JNK-Yki self-reinforcing positive feedback signal-amplification loop that promotes tumor growth. We found that the Wg-Dronc-Yki-JNK molecular network is specifically activated in polarity-impaired tumor cells and not in normal cells, in which apical-basal polarity remains intact. Our findings suggest that the identification of molecular networks may provide significant insights into the key biologically meaningful changes in signaling pathways and paradoxical signals that promote tumorigenesis.

miR-277 targets the proapoptotic gene-hid to ameliorate Aß42-mediated neurodegeneration in Alzheimer's model.

Alzheimer's disease (AD), an age-related progressive neurodegenerative disorder, exhibits reduced cognitive function with no cure to date. One of the reasons for AD is the accumulation of Amyloid-beta 42 (Aß42) plaque(s) that trigger aberrant gene expression and signaling, which results in neuronal cell death by an unknown mechanism(s). Misexpression of human Aß42 in the developing retina of Drosophila exhibits AD-like neuropathology. Small non-coding RNAs, microRNAs (miRNAs), post-transcriptionally regulate the expression of their target genes and thereby regulate different signaling pathways. In a forward genetic screen, we identified miR-277 (human ortholog is hsa-miR-3660) as a genetic modifier of Aß42-mediated neurodegeneration. Loss-of-function of miR-277 enhances the Aß42-mediated neurodegeneration. Whereas gain-of-function of miR-277 in the GMR > Aß42 background downregulates cell death to maintain the number of neurons and thereby restores the retinal axonal targeting defects indicating the functional rescue. In addition, gain-of-function of miR-277 rescues the eclosion- and climbing assays defects observed in GMR > Aß42 background. Thus, gain-of-function of miR-277 rescues both structurally as well as functionally the Aß42-mediated neurodegeneration. Furthermore, we identified head involution defective (hid), an evolutionarily conserved proapoptotic gene, as one of the targets of miR-277 and validated these results using luciferase- and qPCR -assays. In the GMR > Aß42 background, the gain-of-function of miR-277 results in the reduction of hid transcript levels to one-third of its levels as compared to GMR > Aß42 background alone. Here, we provide a novel molecular mechanism where miR-277 targets and downregulates proapoptotic gene, hid, transcript levels to rescue Aß42-mediated neurodegeneration by blocking cell death. These studies shed light on molecular mechanism(s) that mediate cell death response following Aß42 accumulation seen in neurodegenerative disorders in humans and provide new therapeutic targets for neurodegeneration.

Domain specific genetic mosaic system in the Drosophila eye.

Genetic mosaic approach is commonly used in the Drosophila eye by completely abolishing or misexpressing a gene within a subset of cells to unravel its role during development. Classical genetic mosaic approach involves random clone generation in all developing fields. Consequently, a large sample size needs to be screened to generate and analyze clones in specific domains of the developing eye. To address domain specific functions of genes during axial patterning, we have developed a system for generating mosaic clones by combining Gal4/UAS and flippase (FLP)/FRT system which will allow generation of loss-of-function as well as gain-of-function clones on the dorsal and ventral eye margins. We used the bifid-Gal4 driver to drive expression of UAS-FLP. This reagent can have multiple applications in (i) studying spatio-temporal function of a gene during dorso-ventral (DV) axis specification in the eye, (ii) analyzing genetic epistasis of genes involved in DV patterning, and (iii) conducting genome wide screens in a domain specific manner.

Differential adaptive responses of Staphylococcus aureus to in vitro selection with different antimicrobial peptides.

We subjected Staphylococcus aureus ATCC 29213 to serial passage in the presence of subinhibitory concentrations of magainin 2 and gramicidin D for several hundred generations. We obtained S. aureus strains with induced resistance to magainin 2 (strain 55MG) and gramicidin D (strain 55GR) that showed different phenotypic changes in membrane properties. Both exhibited a change in membrane phospholipid content and an increase in membrane rigidity, while an alteration in net charge compared to that of the control occurred only in the case of 55MG.

The tumour-suppressor genes NF2/Merlin and Expanded act through Hippo signalling to regulate cell proliferation and apoptosis.

Merlin, the protein product of the Neurofibromatosis type-2 gene, acts as a tumour suppressor in mice and humans. Merlin is an adaptor protein with a FERM domain and it is thought to transduce a growth-regulatory signal. However, the pathway through which Merlin acts as a tumour suppressor is poorly understood. Merlin, and its function as a negative regulator of growth, is conserved in Drosophila, where it functions with Expanded, a related FERM domain protein. Here, we show that Drosophila Merlin and Expanded are components of the Hippo signalling pathway, an emerging tumour-suppressor pathway. We find that Merlin and Expanded, similar to other components of the Hippo pathway, are required for proliferation arrest and apoptosis in developing imaginal discs. Our genetic and biochemical data place Merlin and Expanded upstream of Hippo and identify a pathway through which they act as tumour-suppressor genes.

A glimpse into dorso-ventral patterning of the Drosophila eye.

During organogenesis in all multi-cellular organisms, axial patterning is required to transform a single layer organ primordium into a three-dimensional organ. The Drosophila eye model serves as an excellent model to study axial patterning. Dorso-ventral (DV) axis determination is the first lineage restriction event during axial patterning of the Drosophila eye. The early Drosophila eye primordium has a default ventral fate, and the dorsal eye fate is established by onset of dorsal selector gene pannier (pnr) expression in a group of cells on the dorsal eye margin. The boundary between dorsal and ventral compartments called the equator is the site for Notch (N) activation, which triggers cell proliferation and differentiation. This review will focus on (1) chronology of events during DV axis determination; (2) how early division of eye into dorsal and ventral compartments contributes towards the growth and patterning of the fly retina, and (3) functions of DV patterning genes.

Synergistic Potential of α-Melanocyte Stimulating Hormone Based Analogues with Conventional Antibiotic against Planktonic, Biofilm-Embedded, and Systemic Infection Model of MRSA.

The repotentiation of the existing antibiotics by exploiting the combinatorial potential of antimicrobial peptides (AMPs) with them is a promising approach to address the challenges of slow antibiotic development and rising antimicrobial resistance. In the current study, we explored the ability of lead second generation Ana-peptides viz. Ana-9 and Ana-10, derived from Alpha-Melanocyte Stimulating Hormone (α-MSH), to act synergistically with different classes of conventional antibiotics against methicillin-resistant Staphylococcus aureus (MRSA). The peptides exhibited prominent synergy with ß-lactam antibiotics, namely, oxacillin, ampicillin, and cephalothin, against planktonic MRSA. Furthermore, the lead combination of Ana-9/Ana-10 with oxacillin provided synergistic activity against clinical MRSA isolates. Though the treatment of MRSA is complicated by biofilms, the lead combinations successfully inhibited biofilm formation and also demonstrated biofilm disruption potential. Encouragingly, the peptides alone and in combination were able to elicit in vivo anti-MRSA activity and reduce the bacterial load in the liver and kidney of immune-compromised mice. Importantly, the presence of Ana-peptides at sub-MIC doses slowed the resistance development against oxacillin in MRSA cells. Thus, this study highlights the synergistic activity of Ana-peptides with oxacillin advocating for the potential of Ana-peptides as an alternative therapeutic and could pave the way for the reintroduction of less potent conventional antibiotics into clinical use against MRSA infections.