Cell division in tissues enables macrophage infiltration.

Cells migrate through crowded microenvironments within tissues during normal development, immune response, and cancer metastasis. Although migration through pores and tracks in the extracellular matrix (ECM) has been well studied, little is known about cellular traversal into confining cell-dense tissues. We find that embryonic tissue invasion by Drosophila macrophages requires division of an epithelial ectodermal cell at the site of entry. Dividing ectodermal cells disassemble ECM attachment formed by integrin-mediated focal adhesions next to mesodermal cells, allowing macrophages to move their nuclei ahead and invade between two immediately adjacent tissues. Invasion efficiency depends on division frequency, but reduction of adhesion strength allows macrophage entry independently of division. This work demonstrates that tissue dynamics can regulate cellular infiltration.

A translation control module coordinates germline stem cell differentiation with ribosome biogenesis during Drosophila oogenesis.

Ribosomal defects perturb stem cell differentiation, and this is the cause of ribosomopathies. How ribosome levels control stem cell differentiation is not fully known. Here, we discover that three DExD/H-box proteins govern ribosome biogenesis (RiBi) and Drosophila oogenesis. Loss of these DExD/H-box proteins, which we name Aramis, Athos, and Porthos, aberrantly stabilizes p53, arrests the cell cycle, and stalls germline stem cell (GSC) differentiation. Aramis controls cell-cycle progression by regulating translation of mRNAs that contain a terminal oligo pyrimidine (TOP) motif in their 5' UTRs. We find that TOP motifs confer sensitivity to ribosome levels that are mediated by La-related protein (Larp). One such TOP-containing mRNA codes for novel nucleolar protein 1 (Non1), a conserved p53 destabilizing protein. Upon a sufficient ribosome concentration, Non1 is expressed, and it promotes GSC cell-cycle progression via p53 degradation. Thus, a previously unappreciated TOP motif in Drosophila responds to reduced RiBi to co-regulate the translation of ribosomal proteins and a p53 repressor, coupling RiBi to GSC differentiation.

Macrophage mitochondrial bioenergetics and tissue invasion are boosted by an Atossa-Porthos axis in Drosophila.

Cellular metabolism must adapt to changing demands to enable homeostasis. During immune responses or cancer metastasis, cells leading migration into challenging environments require an energy boost, but what controls this capacity is unclear. Here, we study a previously uncharacterized nuclear protein, Atossa (encoded by CG9005), which supports macrophage invasion into the germband of Drosophila by controlling cellular metabolism. First, nuclear Atossa increases mRNA levels of Porthos, a DEAD-box protein, and of two metabolic enzymes, lysine-α-ketoglutarate reductase (LKR/SDH) and NADPH glyoxylate reductase (GR/HPR), thus enhancing mitochondrial bioenergetics. Then Porthos supports ribosome assembly and thereby raises the translational efficiency of a subset of mRNAs, including those affecting mitochondrial functions, the electron transport chain, and metabolism. Mitochondrial respiration measurements, metabolomics, and live imaging indicate that Atossa and Porthos power up OxPhos and energy production to promote the forging of a path into tissues by leading macrophages. Since many crucial physiological responses require increases in mitochondrial energy output, this previously undescribed genetic program may modulate a wide range of cellular behaviors.

Fos regulates macrophage infiltration against surrounding tissue resistance by a cortical actin-based mechanism in Drosophila.

The infiltration of immune cells into tissues underlies the establishment of tissue-resident macrophages and responses to infections and tumors. Yet the mechanisms immune cells utilize to negotiate tissue barriers in living organisms are not well understood, and a role for cortical actin has not been examined. Here, we find that the tissue invasion of Drosophila macrophages, also known as plasmatocytes or hemocytes, utilizes enhanced cortical F-actin levels stimulated by the Drosophila member of the fos proto oncogene transcription factor family (Dfos, Kayak). RNA sequencing analysis and live imaging show that Dfos enhances F-actin levels around the entire macrophage surface by increasing mRNA levels of the membrane spanning molecular scaffold tetraspanin TM4SF, and the actin cross-linking filamin Cheerio, which are themselves required for invasion. Both the filamin and the tetraspanin enhance the cortical activity of Rho1 and the formin Diaphanous and thus the assembly of cortical actin, which is a critical function since expressing a dominant active form of Diaphanous can rescue the Dfos macrophage invasion defect. In vivo imaging shows that Dfos enhances the efficiency of the initial phases of macrophage tissue entry. Genetic evidence argues that this Dfos-induced program in macrophages counteracts the constraint produced by the tension of surrounding tissues and buffers the properties of the macrophage nucleus from affecting tissue entry. We thus identify strengthening the cortical actin cytoskeleton through Dfos as a key process allowing efficient forward movement of an immune cell into surrounding tissues.

A conserved major facilitator superfamily member orchestrates a subset of O-glycosylation to aid macrophage tissue invasion.

Aberrant display of the truncated core1 O-glycan T-antigen is a common feature of human cancer cells that correlates with metastasis. Here we show that T-antigen in Drosophila melanogaster macrophages is involved in their developmentally programmed tissue invasion. Higher macrophage T-antigen levels require an atypical major facilitator superfamily (MFS) member that we named Minerva which enables macrophage dissemination and invasion. We characterize for the first time the T and Tn glycoform O-glycoproteome of the Drosophila melanogaster embryo, and determine that Minerva increases the presence of T-antigen on proteins in pathways previously linked to cancer, most strongly on the sulfhydryl oxidase Qsox1 which we show is required for macrophage tissue entry. Minerva's vertebrate ortholog, MFSD1, rescues the minerva mutant's migration and T-antigen glycosylation defects. We thus identify a key conserved regulator that orchestrates O-glycosylation on a protein subset to activate a program governing migration steps important for both development and cancer metastasis.

Biochemical characterization of a novel antioxidant and angiotensin I-converting enzyme inhibitory peptide from Struthio camelus egg white protein hydrolysis.

A peptide from ostrich (Struthio camelus) egg white protein hydrolysate (OEWPH) was purified, characterized, and its antioxidant and enzyme inhibitory properties were evaluated. The OEWPH was prepared using pepsin and pancreatin, and then fractionated using reversed-phase high performance liquid chromatography. The antioxidant activity of the WG-9 peptide was investigated based on its scavenging capacity for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,20-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), superoxide (O2•-), hydroxyl (OH•-), and lipid peroxidation inhibition. The angiotensin-converting enzyme (ACE) inhibitory activity and kinetic parameters of the peptide were determined using N-[3-(2-Furyl)acryloyl]-L-phenylalanyl-glycyl-glycine (FAPGG) as a substrate. Tandem mass spectrometry analysis of the purified peptide revealed a sequence of WESLSRLLG (MW: 1060 Da; WG-9). This peptide inhibited linoleic acid oxidation and acted as a DPPH (IC50 = 15 ± 0.4 µg/mL), ABTS (IC50 = 130 ± 4.5 µg/mL), superoxide (IC50 = 160 ± 6.4 µg/mL), and hydroxyl (IC50 = 150 ± 6.7 µg/mL) radical scavenger. The ACE-inhibitory activity and kinetic parameters of the WG-9 peptide were determined, showing an ACE inhibitory activity with IC50 of 46.7 ± 1.4 µg/mL. The parameters of peptide/ACE interactions were investigated by molecule docking. Furthermore, viability assays showed that the identified peptide had no cytotoxicity against an HFLF-PI-5 cell line. In conclusion, the WG-9 peptide showed potent antioxidant and ACE-inhibitory activity.

Gene cloning and characterization of a thermostable organic-tolerant α-amylase from Bacillus subtilis DR8806.

The gene encoding an extracellular α-amylase from Bacillus subtilis DR8806 was cloned into pET28a(+) vector and expressed in Escherichia coli BL21 (DE3). The recombinant enzyme with molecular mass of 76 kDa exhibited optimal activity at pH 5.0 and 70 °C with high stability in pH and temperature ranges of 4.0-9.0 and 45-75 °C. The enzyme showed a half-life of 125 min at 70 °C. The α-amylase activity enhanced in the presence of Na(+), K(+), and Ca(2+) ions, while Zn(2+), Pb(2+), and Hg(2+) ions inhibited the activity. The recombinant α-amylase exhibited high stability towards ioninc detergents sodium dodecyl sulfate (SDS) and cetyl trimethylammonium bromide (CTAB). Organic solvents in reaction media increased the α-amylase activity. TLC analysis showed that maltoriose and maltose were the major end products of enzymatic starch hydrolysis. Presenting various properties of recombinant α-amylase makes it well suited as a potential candidate for industrial usages.

Expression and biochemical characterization of a thermophilic organic solvent-tolerant lipase from Bacillus sp. DR90.

The objective of the present study was the isolation, molecular cloning and biochemical characterization of a thermophilic organic solvent-resistant lipase from Bacillus sp. DR90. The lipase gene was expressed in Escherichia coli BL21(DE3) using pET-28a(+) vector. The purification of recombinant lipase was conducted by nickel affinity chromatography and its biochemical properties were determined. The lipase sequence with an ORF of 639 bp contains the conserved pentapeptide Ala-His-Ser-Met-Gly. His-tagged recombinant lipase had a specific activity of 1,126 U/mg with a molecular mass of 26.8 kDa. The cloned lipase was optimally active at pH 8.0 and 75 °C representing high stability in broad ranges of temperature and pH. High performance liquid chromatography was used to determine the major compounds released during the lipase-catalyzed reaction of p-nitrophenyl derivatives as well as the substrate specificity. The purified lipase showed high compatibility towards various organic solvents, surfactants and commercial solid/liquid detergents; therefore the recombinant DR90 lipase could be considered as a probable candidate for future applications, predominantly in detergent processing industries.

Antioxidant properties of a human neuropeptide and its protective effect on free radical-induced DNA damage.

Human catestatin CgA352-372 (SL21) is an endogenous neuropeptide with multiple biological functions. The present study aimed to evaluate the antioxidant, antibacterial, cytotoxic, and DNA damage protective effects of SL21 neuropeptide. SL21 neuropeptide generated from the C-terminus of chromogranin A (CgA) was synthesized by solid-phase method. Synthetic peptide was subjected to various in vitro antioxidant assays including the scavenging of 1,1-diphenyl-2-pycryl-hydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(·+) ), and hydroxyl free radicals, metal ion chelation, inhibition of lipid peroxidation, and reducing power. Moreover, protective effect of SL21 on H2 O2 -induced DNA damage was analyzed using pTZ57/RT plasmid. Methylthiazoltetrazolium assay was also performed to study the cytotoxic effect of SL21 neuropeptide on human peripheral blood mononuclear cells. Furthermore, antibacterial and hemolysis assays were conducted. The results demonstrated high activities of SL21 in scavenging free radicals (DPPH, ABTS(·+) , and hydroxyl), chelating of Cu(2+) /Fe(2+) metal ions, reducing power, and inhibition of lipid peroxidation in a concentration-dependent manner. SL21 neuropeptide revealed a protective effect on DNA damage caused by hydroxyl radicals. Interestingly, the peptide exhibited no significant cytotoxicity towards peripheral blood mononuclear cells. Furthermore, SL21 peptide displayed antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa without any hemolytic activity on human red blood cells. Conclusively, the present study established SL21 (catestatin) as a novel antioxidative peptide that could further be investigated for its potential use as a pharmaceutical agent.