A thylakoid biogenesis BtpA protein is required for the initial step of tetrapyrrole biosynthesis in cyanobacteria.

Biogenesis of the photosynthetic apparatus requires complicated molecular machinery, individual components of which are either poorly characterized or unknown. The BtpA protein has been described as a factor required for the stability of photosystem I (PSI) in cyanobacteria; however, how the BtpA stabilized PSI remains unexplained. To clarify the role of BtpA, we constructed and characterized the btpA-null mutant (ΔbtpA) in the cyanobacterium Synechocystis sp. PCC 6803. The mutant contained only c. 1% of chlorophyll and nearly no thylakoid membranes. However, this strain, growing only in the presence of glucose, was genetically unstable and readily generated suppressor mutations that restore the photoautotrophy. Two suppressor mutations were mapped into the hemA gene encoding glutamyl-tRNA reductase (GluTR) - the first enzyme of tetrapyrrole biosynthesis. Indeed, the GluTR was not detectable in the ΔbtpA mutant and the suppressor mutations restored biosynthesis of tetrapyrroles and photoautotrophy by increased GluTR expression or by improved GluTR stability/processivity. We further demonstrated that GluTR associates with a large BtpA oligomer and that BtpA is required for the stability of GluTR. Our results show that the BtpA protein is involved in the biogenesis of photosystems at the level of regulation of tetrapyrrole biosynthesis.

Evolution of Ycf54-independent chlorophyll biosynthesis in cyanobacteria.

Chlorophylls (Chls) are essential cofactors for photosynthesis. One of the least understood steps of Chl biosynthesis is formation of the fifth (E) ring, where the red substrate, magnesium protoporphyrin IX monomethyl ester, is converted to the green product, 3,8-divinyl protochlorophyllide a In oxygenic phototrophs, this reaction is catalyzed by an oxygen-dependent cyclase, consisting of a catalytic subunit (AcsF/CycI) and an auxiliary protein, Ycf54. Deletion of Ycf54 impairs cyclase activity and results in severe Chl deficiency, but its exact role is not clear. Here, we used a Δycf54 mutant of the model cyanobacterium Synechocystis sp. PCC 6803 to generate suppressor mutations that restore normal levels of Chl. Sequencing Δycf54 revertants identified a single D219G amino acid substitution in CycI and frameshifts in slr1916, which encodes a putative esterase. Introduction of these mutations to the original Δycf54 mutant validated the suppressor effect, especially in combination. However, comprehensive analysis of the Δycf54 suppressor strains revealed that the D219G-substituted CycI is only partially active and its accumulation is misregulated, suggesting that Ycf54 controls both the level and activity of CycI. We also show that Slr1916 has Chl dephytylase activity in vitro and its inactivation up-regulates the entire Chl biosynthetic pathway, resulting in improved cyclase activity. Finally, large-scale bioinformatic analysis indicates that our laboratory evolution of Ycf54-independent CycI mimics natural evolution of AcsF in low-light-adapted ecotypes of the oceanic cyanobacteria Prochlorococcus, which lack Ycf54, providing insight into the evolutionary history of the cyclase enzyme.

Efficacy of switches within the class of IL-17 inhibitors: An analysis of data from the Czech nationwide registry of psoriatic patients receiving biological/targeted therapy (BIOREP).

The IL-17 cytokine family encompasses six different homodimers and heterodimers referred to as IL-17A-F. Due to some differences in the mechanism of IL-17 inhibition, aninsufficient effect of one IL-17 inhibitor does not necessarily imply lack of efficacy of the other agent of the same class. Aim of study was analysis of the success rate of switches among IL-17 inhibitors (secukinumab, ixekizumab, and brodalumab) in patients treated in the Czech Republic. Data were obtained from the Czech nationwide registry of psoriatic patients receiving biological/targeted therapy (BIOREP). Our analysis involved data of a total of 90 patients with severe chronic plaque psoriasis and baseline PASI scores >10 both prior to first-line biological therapy initiation and after switch to another agent of the class of IL-17 inhibitors. The most effective switch was that from secukinumab to brodalumab, with PASI 90 reached by 64.7% and 73.3% of patients at weeks 12 and 24. Among patients switched from secukinumab to ixekizumab target PASI 90 responses were achieved (at weeks 12 and 24) by 41.2% and 55.2% of patients. Among patients switched from ixekizumab to brodalumab target PASI 90 responses were achieved, at the above time points, by 30.8% and 38.5% of patients. Our analysis showed a high success rate of switches from secukinumab to ixekizumab and brodalumab, followed by the ixekizumab-to-brodalumab switch. Importantly, the therapeutic response and success rates of individual switches are independent of the patient's body weight and presence of psoriatis arthritis.

The cyanobacterial protoporphyrinogen oxidase HemJ is a new b-type heme protein functionally coupled with coproporphyrinogen III oxidase.

Protoporphyrinogen IX oxidase (PPO), the last enzyme that is common to both chlorophyll and heme biosynthesis pathways, catalyzes the oxidation of protoporphyrinogen IX to protoporphyrin IX. PPO has several isoforms, including the oxygen-dependent HemY and an oxygen-independent enzyme, HemG. However, most cyanobacteria encode HemJ, the least characterized PPO form. We have characterized HemJ from the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis 6803) as a bona fide PPO; HemJ down-regulation resulted in accumulation of tetrapyrrole precursors and in the depletion of chlorophyll precursors. The expression of FLAG-tagged Synechocystis 6803 HemJ protein (HemJ.f) and affinity isolation of HemJ.f under native conditions revealed that it binds heme b The most stable HemJ.f form was a dimer, and higher oligomeric forms were also observed. Using both oxygen and artificial electron acceptors, we detected no enzymatic activity with the purified HemJ.f, consistent with the hypothesis that the enzymatic mechanism for HemJ is distinct from those of other PPO isoforms. The heme absorption spectra and distant HemJ homology to several membrane oxidases indicated that the heme in HemJ is redox-active and involved in electron transfer. HemJ was conditionally complemented by another PPO, HemG from Escherichia coli. If grown photoautotrophically, the complemented strain accumulated tripropionic tetrapyrrole harderoporphyrin, suggesting a defect in enzymatic conversion of coproporphyrinogen III to protoporphyrinogen IX, catalyzed by coproporphyrinogen III oxidase (CPO). This observation supports the hypothesis that HemJ is functionally coupled with CPO and that this coupling is disrupted after replacement of HemJ by HemG.

Binding of pigments to the cyanobacterial high-light-inducible protein HliC.

Cyanobacteria possess a family of one-helix high-light-inducible proteins (HLIPs) that are widely viewed as ancestors of the light-harvesting antenna of plants and algae. HLIPs are essential for viability under various stress conditions, although their exact role is not fully understood. The unicellular cyanobacterium Synechocystis sp. PCC 6803 contains four HLIPs named HliA-D, and HliD has recently been isolated in a small protein complex and shown to bind chlorophyll and ß-carotene. However, no HLIP has been isolated and characterized in a pure form up to now. We have developed a protocol to purify large quantities of His-tagged HliC from an engineered Synechocystis strain. Purified His-HliC is a pigmented homo-oligomer and is associated with chlorophyll and ß-carotene with a 2:1 ratio. This differs from the 3:1 ratio reported for HliD. Comparison of these two HLIPs by resonance Raman spectroscopy revealed a similar conformation for their bound ß-carotenes, but clear differences in their chlorophylls. We present and discuss a structural model of HliC, in which a dimeric protein binds four chlorophyll molecules and two ß-carotenes.

Discovery of a chlorophyll binding protein complex involved in the early steps of photosystem II assembly in Synechocystis.

Efficient assembly and repair of the oxygen-evolving photosystem II (PSII) complex is vital for maintaining photosynthetic activity in plants, algae, and cyanobacteria. How chlorophyll is delivered to PSII during assembly and how vulnerable assembly complexes are protected from photodamage are unknown. Here, we identify a chlorophyll and ß-carotene binding protein complex in the cyanobacterium Synechocystis PCC 6803 important for formation of the D1/D2 reaction center assembly complex. It is composed of putative short-chain dehydrogenase/reductase Ycf39, encoded by the slr0399 gene, and two members of the high-light-inducible protein (Hlip) family, HliC and HliD, which are small membrane proteins related to the light-harvesting chlorophyll binding complexes found in plants. Perturbed chlorophyll recycling in a Ycf39-null mutant and copurification of chlorophyll synthase and unassembled D1 with the Ycf39-Hlip complex indicate a role in the delivery of chlorophyll to newly synthesized D1. Sequence similarities suggest the presence of a related complex in chloroplasts.

Clinicopathological correlations of the immunoprofile in diffuse large B-cell lymphoma NOS - a single institutions experience.

The experimental platform in hematooncology is still searching for more valid prognostic and predictive factors on clinical, morphological and molecular levels. The bridge closer to daily practice is so-called translation medicine and from this point of view we have tried to sort diffuse large B-cell lymphoma not otherwise specified. The applied methodological approaches are morphology, indirect immunohistochemistry on formaline-fixed, parrafin-embeded tissue, Hans classifier sorting, expression of Bcl-2, CD5, CD20, CD30 and NfκB proteins in comparison with the clinical (Ann Arbor stage, IPI, aa-IPI, PFS, OS), laboratory and cytogenetic results (complex and simplex karyotypes). Statistical analysis included Cox regressive analysis, Mann-Whitney and Kruska-Wallis test. The interval of PFS and OS has been assessed according to Kaplan-Meier analysis. According to Hans classifier 11 cases (18.7 %) could not be sorted exactly into GCB/nonGCB- like subgroups. All relapsing cases bear negative expression of CD10 and 28 cases of non-relapsing cases showed positive expression of CD10. The "third" - GCB-like/nonGCB-like unsortable subgroups shared a very similar course of PFS with the nonGCB-like subgroup and a worse clinical course of OS. Statistically nonsignificantly better response to chemotherapy was shown by cases with positive Bcl-2 expression of more than 30 %. Statistically nonsignificantly better OS and PFS was shown by cases with a proliferation index Ki67 more than 70 %. The study detected 17 cases (28.8 %) with a nuclear expression of p50 and one case with nuclear expression of p65 (1.7 %) which may imply the possibility of NfκB signaling pathway activation. A statistically nonsignificant realationship of p50 expression and OS/PFS was indicated.

Two essential FtsH proteases control the level of the Fur repressor during iron deficiency in the cyanobacterium Synechocystis sp. PCC 6803.

The cyanobacterium Synechocystis sp. PCC 6803 expresses four different FtsH protease subunits (FtsH1-4) that assemble into specific homo- and heterocomplexes. The FtsH2/FtsH3 complex is involved in photoprotection but the physiological roles of the other complexes, notably the essential FtsH1/FtsH3 complex, remain unclear. Here we show that the FtsH1 and FtsH3 proteases are involved in the acclimation of cells to iron deficiency. A mutant conditionally depleted in FtsH3 was unable to induce normal expression of the IsiA chlorophyll-protein and FutA1 iron transporter upon iron deficiency due to a block in transcription, which is regulated by the Fur transcriptional repressor. Levels of Fur declined in the WT and the FtsH2 null mutant upon iron depletion but not in the FtsH3 downregulated strain. A similar stabilizing effect on Fur was also observed in a mutant conditionally depleted in the FtsH1 subunit. Moreover, a mutant overexpressing FtsH1 showed reduced levels of Fur and enhanced accumulation of both IsiA and FutA1 even under iron sufficiency. Analysis of GFP-tagged derivatives and biochemical fractionation supported a common location for FtsH1 and FtsH3 in the cytoplasmic membrane. Overall we propose that degradation of the Fur repressor mediated by the FtsH1/FtsH3 heterocomplex is critical for acclimation to iron depletion.

Subunit organization of a synechocystis hetero-oligomeric thylakoid FtsH complex involved in photosystem II repair.

FtsH metalloproteases are key components of the photosystem II (PSII) repair cycle, which operates to maintain photosynthetic activity in the light. Despite their physiological importance, the structure and subunit composition of thylakoid FtsH complexes remain uncertain. Mutagenesis has previously revealed that the four FtsH homologs encoded by the cyanobacterium Synechocystis sp PCC 6803 are functionally different: FtsH1 and FtsH3 are required for cell viability, whereas FtsH2 and FtsH4 are dispensable. To gain insights into FtsH2, which is involved in selective D1 protein degradation during PSII repair, we used a strain of Synechocystis 6803 expressing a glutathione S-transferase (GST)-tagged derivative (FtsH2-GST) to isolate FtsH2-containing complexes. Biochemical analysis revealed that FtsH2-GST forms a hetero-oligomeric complex with FtsH3. FtsH2 also interacts with FtsH3 in the wild-type strain, and a mutant depleted in FtsH3, like ftsH2(-) mutants, displays impaired D1 degradation. FtsH3 also forms a separate heterocomplex with FtsH1, thus explaining why FtsH3 is more important than FtsH2 for cell viability. We investigated the structure of the isolated FtsH2-GST/FtsH3 complex using transmission electron microscopy and single-particle analysis. The three-dimensional structural model obtained at a resolution of 26 Å revealed that the complex is hexameric and consists of alternating FtsH2/FtsH3 subunits.

Manifestation of Crohn's disease in a young woman during the course of treatment for severe form of chronic plaque psoriasis with etanercept.

With the growing number of patients with immune-modulated diseases treated with tumor necrosis factor (TNF) alpha inhibitors, we are more frequently encountering the occurrence of so-called paradoxical drug reactions. These are basically situations where during the course of the treatment of one disease, the manifestation of another with similar etiopathogenesis occurs, although under normal conditions this newly developed disease responds well to treatment with TNF alpha inhibitors and is indicated for this treatment. Skin reactions are most frequently recorded in the form of induced psoriasis and psoriasiform exanthems. A less common paradoxical reaction is the induction of Crohn's disease, which is most often described in association with the treatment of inflammatory joint diseases with etanercept. We present a case of induction of Crohn's disease during therapy with etanercept, where the primary disease being treated was psoriasis. In the literature, similar cases have only been described sporadically.

Life-threatening course of pemphigus vulgaris complicated by sepsis caused by azathioprine-induced bone marrow suppression, successfully managed with combination therapy.

Severe forms of pemphigus vulgaris (PV) that are resistant to standard treatment present a life-threatening disease with a mortality of 5-10%. The treatment is usually individualized. The most popular procedures used today include intravenous applications of immunoglobulins and rituximab. Currently the common use of pulse corticosteroids, often in first-line treatment, is being neglected. This particular case documented the severity of the disease and also the need for combined and comprehensive care, in which corticosteroid pulse therapy still plays an important role.

The cyanobacterial FtsH4 protease controls accumulation of protein factors involved in the biogenesis of photosystem I.

Membrane-bound FtsH proteases are universally present in prokaryotes and in mitochondria and chloroplasts of eukaryotic cells. These metalloproteases are often critical for viability and play both protease and chaperone roles to maintain cellular homeostasis. In contrast to most bacteria bearing a single ftsH gene, cyanobacteria typically possess four FtsH proteases (FtsH1-4) forming heteromeric (FtsH1/3 and FtsH2/3) and homomeric (FtsH4) complexes. The functions and substrate repertoire of each complex are however poorly understood. To identify substrates of the FtsH4 protease complex we established a trapping assay in the cyanobacterium Synechocystis PCC 6803 utilizing a proteolytically inactivated trapFtsH4-His. Around 40 proteins were specifically enriched in trapFtsH4 pulldown when compared with the active FtsH4. As the list of putative FtsH4 substrates contained Ycf4 and Ycf37 assembly factors of Photosystem I (PSI), its core PsaB subunit and the IsiA chlorophyll-binding protein that associates with PSI during iron stress, we focused on these PSI-related proteins. Therefore, we analysed their degradation by FtsH4 in vivo in Synechocystis mutants and in vitro using purified substrates. The data confirmed that FtsH4 degrades Ycf4, Ycf37, IsiA, and also the individual PsaA and PsaB subunits in the unassembled state but not when assembled within the PSI complexes. A possible role of FtsH4 in the PSI life-cycle is discussed.

Functional assignments for the carboxyl-terminal domains of the ferrochelatase from Synechocystis PCC 6803: the CAB domain plays a regulatory role, and region II is essential for catalysis.

Ferrochelatase (FeCH) catalyzes the insertion of Fe(2+) into protoporphyrin, forming protoheme. In photosynthetic organisms, FeCH and magnesium chelatase lie at a biosynthetic branch point where partitioning down the heme and chlorophyll (Chl) pathways occurs. Unlike their mammalian, yeast, and other bacterial counterparts, cyanobacterial and algal FeCHs as well as FeCH2 isoform from plants possess a carboxyl-terminal Chl a/b-binding (CAB) domain with a conserved Chl-binding motif. The CAB domain is connected to the FeCH catalytic core by a proline-rich linker sequence (region II). In order to dissect the regulatory, catalytic, and structural roles of the region II and CAB domains, we analyzed a FeCH ΔH347 mutant that retains region II but lacks the CAB domain and compared it with the ΔH324-FeCH mutant that lacks both these domains. We found that the CAB domain is not required for catalytic activity but is essential for dimerization of FeCH; its absence causes aberrant accumulation of Chl-protein complexes under high light accompanied by high levels of the Chl precursor chlorophyllide. Thus, the CAB domain appears to serve mainly a regulatory function, possibly in balancing Chl biosynthesis with the synthesis of cognate apoproteins. Region II is essential for the catalytic function of the plastid-type FeCH enzyme, although the low residual activity of the ΔH324-FeCH is more than sufficient to furnish the cellular demand for heme. We propose that the apparent surplus of FeCH activity in the wild type is critical for cell viability under high light due to a regulatory role of FeCH in the distribution of Chl into apoproteins.

Research on Low-Cycle Fatigue Engineered Hybrid Sandwich Ski Construction.

This research is aimed at evaluating the effect of low-cycle fatigue on a newly designed hybrid sandwich ski structure to determine the changes that may occur due to cyclic loading and thus affect its use. This is primarily concerned with the fatigue behavior of the tested ski over different time intervals simulating its seasonal use and its effect on the mechanical properties of the ski, i.e., the durability and integrity of the individual layers of the sandwich ski structure. The ski was subjected to 70,000 deflections by moving the crossbar by 60 mm according to the ski deflection calculation in the arch. The results of the cyclic tests of the engineered ski design showed no significant changes in the ski during loading. The average force required to achieve deflection in the first 10,000 cycles was 514.0 ± 4.2 N. Thereafter, a secondary hardening of the structure occurred during relaxation and the force required increased slightly to 543.6 ± 1.7 N. The required force fluctuated slightly during the measurements and in the last series the value was 540.4 ± 0.8 N. Low-cycle fatigue did not have a significant effect on the mechanical properties of the ski; there was no change in shape or visual delamination of the individual layers of the structure. From the cross-section, local delamination was demonstrated by image analysis, especially between the Wood core and the composite layers E-Glass biaxial and Carbon triaxial.

Efficacy, safety, and drug survival of patients with psoriasis treated with IL-17 inhibitors - brodalumab, ixekizumab, and secukinumab: real-world data from the Czech Republic BIOREP registry.

BACKGROUND: Real-world data on the use of interleukin-17 (IL-17) inhibitors for the treatment of psoriasis are limited. OBJECTIVE: To evaluate and compare the efficacy, safety, and drug survival of IL-17 inhibitors. METHODS: This retrospective study analyzed the BIOREP registry data of patients treated with at least one IL-17 inhibitor (secukinumab, ixekizumab, and brodalumab). RESULTS: In total, 949 patients were included. The improvement in PASI score was significant for all drugs, and the proportion of patients achieving PASI 75, 90, and 100 after both 3 and 24 months of therapy was highest for brodalumab, followed by ixekizumab and secukinumab. The Dermatology Life Quality Index score decreased to ˂3 after 3 months and to ˂2 after 24 months of therapy for all inhibitors. Loss of effectiveness was the major reason for discontinuation in 17.2% of patients, followed by adverse events in 3.2% of patients. The drug survival probability was the highest for brodalumab, followed by ixekizumab and secukinumab. Negative predictors for treatment discontinuation were obesity and the number of treatment lines, whereas a positive predictor was the presence of concomitant psoriatic arthritis; sex had no influence. CONCLUSION: This real-life study demonstrated the effectiveness and good safety profile of all currently available IL-17 inhibitors.

Role of FtsH2 in the repair of Photosystem II in mutants of the cyanobacterium Synechocystis PCC 6803 with impaired assembly or stability of the CaMn(4) cluster.

The FtsH2 protease, encoded by the slr0228 gene, plays a key role in the selective degradation of photodamaged D1 protein during the repair of Photosystem II (PSII) in the cyanobacterium Synechocystis sp. PCC 6803. To test whether additional proteases might be involved in D1 degradation during high rates of photodamage, we have studied the synthesis and degradation of the D1 protein in DeltaPsbO and DeltaPsbV mutants, in which the CaMn(4) cluster catalyzing oxygen evolution is less stable, and in the D1 processing mutants, D1-S345P and DeltaCtpA, which are unable to assemble a functional cluster. All four mutants exhibited a dramatically increased rate of D1 degradation in high light compared to the wild-type. Additional inactivation of the ftsH2 gene slowed the rate of D1 degradation dramatically and increased the level of PSII complexes. We conclude that FtsH2 plays a major role in the degradation of both precursor and mature forms of D1 following donor-side photoinhibition. However, this conclusion concerned only D1 assembled into larger complexes containing at least D2 and CP47. In the DeltapsbEFLJ deletion mutant blocked at an early stage in PSII assembly, unassembled D1 protein was efficiently degraded in the absence of FtsH2 pointing to the involvement of other protease(s). Significantly, the DeltaPsbO mutant displayed unusually low levels of cellular chlorophyll at extremely low-light intensities. The possibilities that PSII repair may limit the availability of chlorophyll for the biogenesis of other chlorophyll-binding proteins and that PsbO might have a regulatory role in PSII repair are discussed.

A Manifestation of Ulcerative Colitis During Treatment for Severe Plaque Psoriasis with Ixekizumab - A Report of Two Cases and Review of the Literature.

L-17 inhibitors belong to the group of the most effective and highly safe biological preparations intended for the treatment of psoriasis, and in the case of secukinumab and ixekizumab, also for the treatment of some immune-mediated inflammatory diseases of the joints. Despite initial expectations, they did not prove to be effective for the treatment of non-specific bowel inflammations (IBD). On the contrary, IBD worsening was reported in some cases where IL-17 inhibitors were used, and registration studies were terminated for this indication. In clinical studies, extensive meta-analyses of IL-17 inhibitor use for psoriasis and joint inflammation indications generally did not demonstrate any statistically significant increase in the risk of de-novo IBD with this type of treatment. Data from real-time practice are mostly similar. The literature describes individual cases with an obvious relation of de novo IBD development subsequent to treatment with IL-17 inhibitors in registered indications. The activation of latent, thus far clinically asymptomatic bowel inflammation is usually expected. Therefore, a careful review of medical history focused on bowel problems in personal and family history is necessary before starting therapy with IL-17 inhibitors. We present a similar experience with de novo onset of ulcerative colitis in two patients treated for psoriasis with ixekizumab, with associated psoriatic arthritis in one case.

Infrared thermography and capillaroscopy in the diagnosis of Raynaud's phenomenon.

AIMS: Raynaud's phenomenon (RP) is a relatively common disease. There are two distinct forms of RP - primary (PRP), where no other associated diseases are present, and secondary (SRP), where RP is associated with other diseases. It can be challenging to differentiate between RP and other diseases through medical history alone, due to the episodic nature of RP. Objective analysis of anamnestic data was performed in our study using infrared thermography (IRT) and a cold pressor test (CPT). Capillaroscopy was performed to assess morphological changes in the acral circulation. METHODS: Patients with a history of cold hands were included in the study. IRT was performed before and after the CPT, and then capillaroscopy was performed. The results (including epidemiologic data) were statistically evaluated. RESULTS: A total of 150 patients were included in the study. Summarisation of the results from the IRT and capillaroscopy determined the final diagnosis - 4.7% acrocyanosis, 10.7% physiologic findings, 31.3% PRP, 29.3% borderline SRP and 24% SRP. The coldest fingers following the CPT were, in most patients, the 2nd and 3rd fingers. The correlation between the presence of connective tissue disease and the diagnosis of borderline SRP and SRP was significant (P=0.0001). CONCLUSIONS: Using the combination of the IRT and capillaroscopy in the diagnostic algorithm for RP has its justification. IRT distinguishes healthy patients from patients with RP, and capillaroscopy can then be used to differentiate PRP from SRP. IRT can also detect which fingers are more affected, and then these can direct the focus of capillaroscopy.

Characterization of Hybrid Composites with Polyester Waste Fibers, Olive Root Fibers and Coir Pith Micro-Particles Using Mixture Design Analysis for Structural Applications.

In the present work, hybrid composites were developed by using polyester waste fibers along with natural origin materials: olive root fibers and coir pitch filler. Such composite panels can be used as a potential alternative for fiber glass sunshade panels and room dividers in buildings. Hybrid composites were fabricated by mixing polyester waste fibers and olive root fibers in different ratios (0:100, 33:67, 67:33 and 100:0). Coir pith micro-particles with an average size of 312 d.nm were used as filler in the polyester matrix at three different levels (0%, 5%, and 10%) of the overall matrix weight. Mechanical properties, e.g., tensile strength, flexural strength and impact strength, thermal properties, e.g., coefficient of linear thermal expansion, thermo-gravimetric analysis (TGA) and environmental properties, e.g., water absorption, loss of density after exposure to weathering were characterized. For comparison purposes, a commercially available fiber glass sunshades sample was also investigated. Mixture design analysis was used to optimize the ratio of all components in the composite. Graphical comparison of experimental results using regression models showed a high degree of correlation. An optimized formulation of composite with an objective of maximization of tensile strength, flexural strength, impact strength and minimization of water absorption, density loss, as well as coefficient of linear thermal expansion, was determined at 70.83 wt%, 15.15 wt%, and 14.01 wt% of polyester waste fibers, olive root fibers and coir pith micro-fillers, respectively. Overall, it can be concluded that the developed hybrid composites from waste fibrous materials can be used as a promising alternative and a value-added application in buildings and construction purposes.